Engineering › Aerospace Engineering

High-Temperature Coating Behaviors

Works Count: 47027

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Description

This cluster of papers focuses on advancements in thermal barrier coatings for gas turbine engines, covering topics such as cold spray deposition, high-temperature corrosion, plasma spraying, rare-earth zirconates, oxidation behavior, bonding mechanisms, microstructural evolution, and thermal conductivity. The research aims to improve the durability and efficiency of thermal barrier coatings in high-temperature environments.

Keywords

Thermal Barrier Coatings; Gas Turbine Engines; Cold Spray Deposition; High-Temperature Corrosion; Plasma Spraying; Rare-Earth Zirconates; Oxidation Behavior; Bonding Mechanisms; Microstructural Evolution; Thermal Conductivity

Bonding mechanism in cold gas spraying

2003-06-30

H. Assadi , F. Gärtner , T. Stoltenhoff +1 more

Thermal barrier coatings technology: critical review, progress update, remaining challenges and prospects

2013-04-05

R. Darolia

A comprehensive and integrated review of thermal barrier coatings (TBCs) applied to turbine components is provided. Materials systems, processes, applications, durability issues, technical approaches and progress for improved TBC, and … A comprehensive and integrated review of thermal barrier coatings (TBCs) applied to turbine components is provided. Materials systems, processes, applications, durability issues, technical approaches and progress for improved TBC, and our understanding of the science and technology are discussed. Thermal barrier coating prime reliance and further advances have been hampered by TBC loss by particle impact and erosion in certain locations of the turbine blades. Accumulation of low melting eutectic containing calcia, magnesia, alumina and silica resulting in TBC spallation limits maximum surface temperature. Design methodologies to address durability and data scatter issues are discussed. Compositions, morphology, characteristics and performance data for new bonds to achieve longer TBC life are described. Further reduction in the thermal conductivity of the top layer to minimise the parasitic mass of the coating on the component is being sought via top layer composition and processing modifications as well as by alternate ceramic compositions. The progress in these areas is critically reviewed including processing, stability and durability limitations. The paper also describes effort to understand various failure mechanisms including modelling and simulation.

Current status of thermal barrier coatings — An overview

1987-01-01

Robert A. Miller

Kinetics, Microstructures and Mechanism of Internal Oxidation - Its Effect and Prevention in High Temperature Alloy Oxidation

1965-12-01

Robert A. Rapp

Abstract A review and evaluation of the role of internal oxidation in the oxidation of alloys is presented and five alloy types represented by Ag-In, Cu-Be, Ni-Cr, Nb-Zr and Cu-Zn-Al … Abstract A review and evaluation of the role of internal oxidation in the oxidation of alloys is presented and five alloy types represented by Ag-In, Cu-Be, Ni-Cr, Nb-Zr and Cu-Zn-Al are considered in detail. Internal oxidation is a diffusion-controlled process for which the kinetics may be predicted from solutions of the diffusion equation. Except for oxidations involving the formation of extremely stable solute oxide precipitates or oxidations at temperatures allowing only minimal solute mobility, the experimentally measured kinetics are in agreement with the calculated rates. The radius of a spherical internal oxide precipitate is expected to vary directly with the depth at which the precipitate is formed and inversely with the oxygen solubility at the external surface. Upon exceeding a critical solute content in a given binary alloy system, the occurrence of internal oxidation of the solute is replaced by the formation of an external scale of the solute metal oxide. A reduction in the oxygen content at the surface or the introduction of deformation into the surface of the alloy can reduce the solute content required for the transition from internal to external oxidation. In most cases, the prevention of internal oxidation by the formation of a compact surface layer of the solute oxide will result in a reduction of the oxidation rate of an alloy. When internal oxidation of a solute occurs in combination with external scale formation, the morphology of the precipitates in the microstructure of the oxidized alloy is determined both by the precipitation conditions and the mode of external scale formation. Internal oxide precipitates can affect both the mechanism and kinetics of external scale formation.

The influence of oxides on the performance of advanced gas turbines

2008-01-01

A.G. Evans , D.R. Clarke , Carlos G. Levi

Thermochemical Interaction of Thermal Barrier Coatings with Molten CaO–MgO–Al2O3–SiO2 (CMAS) Deposits

2006-09-05

Stephan Krämer , Zhenjun Yang , Carlos G. Levi +1 more

Thermal barrier coatings (TBCs) are increasingly susceptible to degradation by molten calcium–magnesium alumino silicate (CMAS) deposits in advanced engines that operate at higher temperatures and in environments laden with siliceous … Thermal barrier coatings (TBCs) are increasingly susceptible to degradation by molten calcium–magnesium alumino silicate (CMAS) deposits in advanced engines that operate at higher temperatures and in environments laden with siliceous debris. This paper investigates the thermochemical aspects of the degradation phenomena using a model CMAS composition and ZrO 2 –7.6%YO 1.5 (7YSZ) grown by vapor deposition on alumina substrates. The changes in microstructure and chemistry are characterized after isothermal treatments of 4 h at 1200°–1400°C. It is found that CMAS rapidly penetrates the open structure of the coating as soon as melting occurs, whereupon the original 7YSZ dissolves in the CMAS and reprecipitates with a different morphology and composition that depends on the local melt chemistry. The attack is minimal in the bulk of the coating but severe near the surface and the interface with the substrate, which is also partially dissolved by the melt. The phase evolution is discussed in terms of available thermodynamic information.

Progress in coatings for gas turbine airfoils

1998-10-01

G.W. Goward

Multi‐Principal‐Element Alloys with Improved Oxidation and Wear Resistance for Thermal Spray Coating

2004-02-05

Pin-shuo Huang , J.‐W. Yeh , Tao-Tsung Shun +1 more

Multi‐principal‐element alloy coatings of Al‐Si alloys were prepared by a plasma spray method. They not only exhibited a good oxidation resistance up to 1000 °C, but also possessed an excellent … Multi‐principal‐element alloy coatings of Al‐Si alloys were prepared by a plasma spray method. They not only exhibited a good oxidation resistance up to 1000 °C, but also possessed an excellent abrasive wear resistance approximately two times higher than those of SUJ2 and SKD61. Moreover, they displayed a high temperature precipitation hardening phenomenon up to 1100 °C which is novel and seldom found in conventional alloys.

Failure mechanisms associated with the thermally grown oxide in plasma-sprayed thermal barrier coatings

2000-09-01

Afsaneh Rabiei , A.G. Evans

Microstructure, adhesion and growth kinetics of protective scales on metals and alloys

1982-12-01

H. Hindam , D. P. Whittle

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Zirconates as New Materials for Thermal Barrier Coatings

2000-08-01

Robert Vaßen , Xueqiang Cao , Frank Tietz +2 more

Zirconates with high melting points were investigated for application as materials for thermal barrier coatings at operating temperatures >1300°C. SrZrO 3 , BaZrO 3 , and La 2 Zr 2 … Zirconates with high melting points were investigated for application as materials for thermal barrier coatings at operating temperatures >1300°C. SrZrO 3 , BaZrO 3 , and La 2 Zr 2 O 7 powders were synthesized and sintered to compacts with various levels of porosity. The sintering results indicated a promising low‐sintering activity of the investigated materials. Thermal properties of these dense materials were determined. Thermal expansion coefficients were slightly lower than those of Y 2 O 3 ‐stabilized ZrO 2 (YSZ); thermal conductivities of SrZrO 3 and BaZrO 3 were comparable or slightly higher than those of YSZ. La 2 Zr 2 O 7 had a lower thermal conductivity. SrZrO 3 was not suitable for application as a thermal barrier coating because of a phase transition at temperatures between 700° and 800°C. Mechanical properties (hardness, fracture toughness, and Young's modulus) of dense BaZrO 3 and La 2 Zr 2 O 7 samples were determined by indentation techniques and showed lower hardness and Young's modulus compared to YSZ. BaZrO 3 and La 2 Zr 2 O 7 powders were optimized for application as powders for plasma spraying. Plasma‐sprayed coatings were produced and characterized. Thermal cycling with a gas burner at 1200°C showed a massive attack of the BaZrO 3 coating, with loss of BaO. On the other hand, the La 2 Zr 2 O 7 coating showed excellent thermal stability and thermal shock behavior.

Theoretical Analysis of the Diffusion Processes Determining the Oxidation Rate of Alloys

1952-01-01

Carl Wagner

The interplay of diffusion processes in metallic and oxide phases during the oxidation of alloys is analyzed theoretically for specified ideal conditions. The interplay of diffusion processes in metallic and oxide phases during the oxidation of alloys is analyzed theoretically for specified ideal conditions.

Overview on advanced thermal barrier coatings

2010-09-23

Robert Vaßen , Maria Ophelia Jarligo , T. Steinke +2 more

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The Hotter the Engine, the Better

2009-11-20

John H. Perepezko

Alloys based on molybdenum or niobium may allow the high-temperature components of jet engines to run hotter and more efficiently. Alloys based on molybdenum or niobium may allow the high-temperature components of jet engines to run hotter and more efficiently.

U.S. Program on Materials Technology for Ultra-Supercritical Coal Power Plants

2005-06-01

R. Viswanathan , Jeff Henry , J. M. Tanzosh +4 more

Hot corrosion in gas turbine components

2002-02-01

Noam Eliaz , G. Shemesh , R. M. Latanision

Understanding plasma spraying

2004-04-15

P. Fauchais

This article intends to summarize our actual knowledge in plasma spraying with an emphasis on the points where work is still in progress. It presents successively: the plasma torches with … This article intends to summarize our actual knowledge in plasma spraying with an emphasis on the points where work is still in progress. It presents successively: the plasma torches with the resulting plasma jets and their interactions with the surrounding environment; the powder injection with the heat, momentum and mass transfers between particles and first plasma jets and then plasma plume; the particles flattening and solidification, forming splats which then layer to form the coating; the latest developments related to the production of plasma sprayed finely structured coatings.

From Particle Acceleration to Impact and Bonding in Cold Spraying

2009-08-05

Tobias Schmidt , H. Assadi , F. Gärtner +4 more

In conventional thermal spraying, the spray particles are partially or fully molten when they deposit on the substrate. Cold spraying, in contrast, uses less thermal and more kinetic energy. In … In conventional thermal spraying, the spray particles are partially or fully molten when they deposit on the substrate. Cold spraying, in contrast, uses less thermal and more kinetic energy. In this process, solid particles impact on the substrate at high velocities and form excellent coatings. Due to comparatively low temperatures and typically inert process gases, cold spraying is particularly suitable for heat and oxidation sensitive materials. In recent years, modeling and computational methods have been widely used to study this relatively new spraying process, particularly to describe impact conditions of particles, to improve nozzle design, and to provide a better understanding of the thermo-mechanical processes that lead to particle bonding and deposition. This paper summarizes the state of the art in these theoretical studies, alongside a comprehensive description of the process. The paper also discusses the prediction of coating properties in the light of modeling combined with experimental investigations.

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Thermal-barrier coatings for more efficient gas-turbine engines

2012-10-01

David R. Clarke , Matthias Oechsner , Nitin P. Padture

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An Analysis of the Cold Spray Process and Its Coatings

2002-12-01

T. Stoltenhoff , H. Kreye , H.J. Richter

Thermal barrier coatings for aircraft engines: history and directions

1997-03-01

Robert A. Miller

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Experimental observations in support of the dynamic-segregation theory to explain the reactive-element effect

1996-02-01

Bruce A. Pint

Thermal barrier coating materials

2005-06-01

David R. Clarke , Simon R. Phillpot

Improved thermal barrier coatings (TBCs) will enable future gas turbines to operate at higher gas temperatures. Considerable effort is being invested, therefore, in identifying new materials with even better performance … Improved thermal barrier coatings (TBCs) will enable future gas turbines to operate at higher gas temperatures. Considerable effort is being invested, therefore, in identifying new materials with even better performance than the current industry standard, yttria-stabilized zirconia (YSZ). We review recent progress and suggest that an integrated strategy of experiment, intuitive arguments based on crystallography, and simulation may lead most rapidly to the development of new TBC materials.

Thermal Barrier Coatings for Gas-Turbine Engine Applications

2002-04-12

Nitin P. Padture , Maurice Gell , Eric H. Jordan

Hundreds of different types of coatings are used to protect a variety of structural engineering materials from corrosion, wear, and erosion, and to provide lubrication and thermal insulation. Of all … Hundreds of different types of coatings are used to protect a variety of structural engineering materials from corrosion, wear, and erosion, and to provide lubrication and thermal insulation. Of all these, thermal barrier coatings (TBCs) have the most complex structure and must operate in the most demanding high-temperature environment of aircraft and industrial gas-turbine engines. TBCs, which comprise metal and ceramic multilayers, insulate turbine and combustor engine components from the hot gas stream, and improve the durability and energy efficiency of these engines. Improvements in TBCs will require a better understanding of the complex changes in their structure and properties that occur under operating conditions that lead to their failure. The structure, properties, and failure mechanisms of TBCs are herein reviewed, together with a discussion of current limitations and future opportunities.

Mechanisms controlling the durability of thermal barrier coatings

2001-01-01

A.G. Evans , Daniel R. Mumm , John W. Hutchinson +2 more

A quantitative demonstration of the grain boundary diffusion mechanism for the oxidation of metals

1982-05-01

A. Atkinson , R. I. Taylor , A.E. Hughés

Abstract Below 1000°C the oxidation of nickel cannot be controlled by the diffusion of ions through the bulk crystal lattice of the pure oxide, because the measured oxidation rates are … Abstract Below 1000°C the oxidation of nickel cannot be controlled by the diffusion of ions through the bulk crystal lattice of the pure oxide, because the measured oxidation rates are several orders of magnitude faster than would be predicted on this basis. Short-circuit diffusion through oxide grain boundaries or dislocations has usually been held responsible, but there has hitherto been no proper quantitative confirmation of this mechanism. We report measurements of the oxide scale thickness and oxide grain size as a function of time during the oxidation of high-purity nickel in the temperature range 500–800°C. All the oxidation experiments were carried out in pure oxygen at a pressure of one atmosphere. The measured parabolic oxidation rate constants have been compared with those calculated from grain boundary diffusion data obtained in our previous work, using a grain boundary diffusion model for the oxidation process. The quantitative agreement between measured and calculated oxidation rates shows convincingly that the diffusion of nickel along oxide grain boundaries controls the oxidation of nickel in these experiments. Oxidation data in the literature can also be accounted for with this model.

Development of a generalized parameter window for cold spray deposition

2005-12-02

Tobias Schmidt , F. Gärtner , H. Assadi +1 more

The oxidation behaviour of metals and alloys at high temperatures in atmospheres containing water vapour: A review

2007-12-06

S. R. J. Saunders , Mauricio Monteiro , Fernando Cosme Rizzo Assunção

Improvements in high temperature oxidation resistance by additions of reactive elements or oxide dispersions

1980-02-07

D. P. Whittle , J. Stringer

The improvement in oxidation resistance of high temperature alloys as a result of additions of rare earth elements, other reactive metals, or dispersions of stable oxides, has been known for … The improvement in oxidation resistance of high temperature alloys as a result of additions of rare earth elements, other reactive metals, or dispersions of stable oxides, has been known for many years. Two effects seem the most important: first, the adhesion between scale and alloy is markedly improved and this increases the alloy’s resistance to thermal cycling exposure; secondly, in some but not all cases the actual growth rate of the oxide is also reduced. The various models proposed to explain these phenomena are discussed in the light of currently available experimental evidence. The most significant of these involve modification to the early, transient stages of oxidation, doping of the oxide which changes its transport properties, mechanical keying of the surface scale to the substrate by the formation of intrusions of oxide penetrating into the alloy and the elimination of void formation at the alloy-scale interface. The efficacies of the various beneficial additions are compared.

Transport processes during the growth of oxide films at elevated temperature

1985-04-01

A. Atkinson

The current understanding of the growth of thermal oxide films in terms of the transport properties of the oxides is reviewed. Emphasis is placed on examining quantitative relationships between the … The current understanding of the growth of thermal oxide films in terms of the transport properties of the oxides is reviewed. Emphasis is placed on examining quantitative relationships between the film growth rate and other measurable parameters of the oxides. The theories of film growth which are expected to apply in the extreme limits of thick films (Wagner) and thin films (Cabrera and Mott) are outlined. Particular attention is given to examining the expected limits of validity of these theories and to the various ways in which their predictions can be tested experimentally. The growth of a selection of important oxides is then discussed in the light of these two theories. The examples (CoO, NiO, ${\mathrm{Fe}}_{3}$${\mathrm{O}}_{4}$, ${\mathrm{Cr}}_{2}$${\mathrm{O}}_{3}$, ${\mathrm{Al}}_{2}$${\mathrm{O}}_{3}$, and Si${\mathrm{O}}_{2}$) have been selected such that together they serve to test the theories, have technological relevance, and exhibit a wide variation in behavior. The dominant role of diffusion along oxide grain boundaries in controlling the growth of the crystalline oxides is highlighted.

Aerosol Deposition of Ceramic Thick Films at Room Temperature: Densification Mechanism of Ceramic Layers

2006-04-29

Jun Akedo

A novel method for depositing ceramic thick films by aerosol deposition (AD) is presented. Submicron ceramics particles are accelerated by gas flow up to 100–500 m/s and then impacted on … A novel method for depositing ceramic thick films by aerosol deposition (AD) is presented. Submicron ceramics particles are accelerated by gas flow up to 100–500 m/s and then impacted on a substrate, to form a dense, uniform and hard ceramic layer at room temperature. However, actual deposition mechanism has not been clarified yet. To clarify densification mechanism during AD, a mixed aerosol of α-Al2O3 and Pb(Zr, Ti)O3 powder was deposited to form a composite layer in this study. The cross-section of the layer was observed by HR-TEM to investigate the densification and bonding mechanism of ceramic particles. As a result, a plastic deformation of starting ceramic particles at room temperature was observed.

Gas Dynamic Principles of Cold Spray

1998-06-01

R.C. Dykhuizen , Mark F. Smith

Adiabatic shear instability based mechanism for particles/substrate bonding in the cold-gas dynamic-spray process

2004-06-09

M. Grujičić , Changtai Zhao , W.S DeRosset +1 more

Cold spray coating: review of material systems and future perspectives

2014-04-16

Atieh Moridi , S.M. Hassani-Gangaraj , Mario Guagliano +1 more

Cold gas dynamic spray or simply cold spray (CS) is a process in which solid powders are accelerated in a de Laval nozzle toward a substrate. If the impact velocity … Cold gas dynamic spray or simply cold spray (CS) is a process in which solid powders are accelerated in a de Laval nozzle toward a substrate. If the impact velocity exceeds a threshold value, particles endure plastic deformation and adhere to the surface. Different materials such as metals, ceramics, composites and polymers can be deposited using CS, creating a wealth of interesting opportunities towards harvesting particular properties. CS is a novel and promising technology to obtain surface coating, offering several technological advantages over thermal spray since it utilizes kinetic rather than thermal energy for deposition. As a result, tensile residual stresses, oxidation and undesired chemical reactions can be avoided. Development of new material systems with enhanced properties covering a wide range of required functionalities of surfaces and interfaces, from internal combustion engines to biotechnology, brought forth new opportunities to the cold spraying with a rich variety of material combinations. As applications multiply, the total number of studies on this subject is expanding rapidly and it is worth summarizing the current state of knowledge. This review covers different material systems that have been studied up to now with an emphasis on potential innovative applications. This includes metallic, ceramic and metal matrix composite (MMC) coatings and their applications. Polymer (both as substrate and coating) and metal embedment in the polymer are also covered. CS has emerged as a promising process to deposit nanostructured materials without significantly altering their microstructure whereas many traditional consolidation processes do. Relevant material systems containing nanostructured powders are also considered. A critical discussion on the future of this technology is provided at the final part of the paper focusing on the microstructural bonding mechanisms for those relatively less explored material systems. These include MMCs involving more than one constituent, ceramics, polymers and nanostructured powders. Future investigations are suggested especially to quantitatively link the process parameters and the behaviour of the material systems of interest during impact.

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Oxidation of Ni-Cr-Al Alloys Between 1000° and 1200°C

1971-01-01

C. S. Giggins , F. S. Pettit

The oxidation of alloys in 0.1 atm of oxygen has been studied at temperatures of 1000°, 1100°, and 1200°C. Twenty‐one alloys with varying chromium [2–30 weight per cent (w/o)] and … The oxidation of alloys in 0.1 atm of oxygen has been studied at temperatures of 1000°, 1100°, and 1200°C. Twenty‐one alloys with varying chromium [2–30 weight per cent (w/o)] and aluminum (1–9 w/o) contents were examined. It was found that all of the alloys initially underwent a period of transient oxidation before steady‐state conditions were established. The transient period of oxidation usually did not exceed 1 hr and was characterized by rapid conversion of thin surface layers of the alloys to oxides with the subsequent formation of continuous layers of one of the following oxides: , , or . Steady‐state conditions were established with the formation of these continuous oxide layers, and oxidation occurred by three different mechanisms which were characterized by the growth of an external layer of over a subscale of and Al2O3, the growth of an external layer of over an subscale or the growth of a continuous, external layer of .

Emerging materials and processes for thermal barrier systems

2004-01-01

Carlos G. Levi

Materials Design for the Next Generation Thermal Barrier Coatings

2003-07-02

David R. Clarke , Carlos G. Levi

▪ Abstract The emphasis in this short review is to describe the materials issues involved in the development of present thermal barrier coatings and the advances necessary for the next … ▪ Abstract The emphasis in this short review is to describe the materials issues involved in the development of present thermal barrier coatings and the advances necessary for the next generation, higher temperature capability coatings.

Ceramic materials for thermal barrier coatings

2003-05-19

Xia Cao , Robert Vaßen , D. Stoever

Thermal Spray Fundamentals

2014-01-01

P. Fauchais , J. Heberlein , Maher I. Boulos

Cold spraying – A materials perspective

2016-06-28

H. Assadi , H. Kreye , F. Gärtner +1 more

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Advanced structural ceramics in aerospace propulsion

2016-07-22

Nitin P. Padture

Corrosion of Al CoCrFeNi high-entropy alloys: Al-content and potential scan-rate dependent pitting behavior

2017-02-16

Yunzhu Shi , Bin Yang , Xie Xie +3 more

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Cold spray additive manufacturing and repair: Fundamentals and applications

2018-04-17

Shuo Yin , Pasquale Cavaliere , Barry Aldwell +4 more

The oxidation behaviour of NiAl-I. Phase transformations in the alumina scale during oxidation of NiAl and NiAl-Cr alloys

1992-11-01

M. Brumm , H. J. Grabke

Low‐Thermal‐Conductivity Rare‐Earth Zirconates for Potential Thermal‐Barrier‐Coating Applications.

2003-03-11

Wu Jie , Xuezheng Wei , Nitin P. Padture +5 more

Abstract For Abstract see ChemInform Abstract in Full Text. Abstract For Abstract see ChemInform Abstract in Full Text.

High Temperature Oxidation and Corrosion of Metals

2008-01-01

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High Temperature Oxidation and Corrosion of Metals

2016-01-01

David J. Young

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Study on the Corrosion Resistance of Laser Remelting/Diamond-Like Carbon Composite Coatings on Stainless Steel Surface

2025-06-25

Sai Li , Dongxu Chen , Xingang Ai +3 more | Journal of Materials Engineering and Performance

An Overview of Rare Earth-Doped Ceramic Thermal Barrier Coatings for High-Temperature Performance of Nickel-Based Superalloys

2025-06-24

Dinesh Diwahar , Vasumathi Manivachakan , S. Rashia Begum | Deleted Journal

Influence of Hydrogen Fuel Mixtures on the Oxide Scale Formation of Low‐Carbon Steels in Reheating Furnace Conditions

2025-06-23

Francis Gyakwaa , Susanna Airaksinen , Ville‐Valtteri Visuri +2 more | steel research international

The introduction of hydrogen is considered pivotal in replacing natural gas in reheating furnaces and decarbonizing the steel industry. Substituting natural gas with hydrogen as fuel will change the composition … The introduction of hydrogen is considered pivotal in replacing natural gas in reheating furnaces and decarbonizing the steel industry. Substituting natural gas with hydrogen as fuel will change the composition of the furnace atmosphere and may influence the scale formed on the steel surface. The study examines oxide scale formation rates of two low‐carbon steels by simulating combustion atmospheres representing five fuels: natural gas (100% CH 4 ), hydrogen (100% H 2 ), and three CH 4 –H 2 fuel blends (75% CH 4 %–25% H 2 , 50% CH 4 %–50% H 2 %, and 25% CH 4 %–75% H 2 ) with varying free oxygen contents. Thermogravimetric analysis and characterization techniques are used to investigate oxidation behavior and the formation of oxide phases. The amount of scale formed for a fuel blend from 100% CH 4 to 100% H 2 shows moderate scale growth and no noticeable evolution changes in oxide phases compared with natural gas in simulated reheating conditions. Higher concentrations of free oxygen exhibit an increase in the oxide scale formed on the steel surface. Metallographic analysis shows that an atmosphere corresponding to 100% H 2 has an increased oxide scale thickness compared with 100% CH 4 . Iron oxide phases, mainly magnetite and wustite, are identified in the samples using various characterization techniques.

Crack Propagation Mechanism in Thermal Barrier Coatings Containing Different Residual Grit Particles Under Thermal Cycling

2025-06-23

Xin Shen , Zhi-Yuan Wei , Zhenghao Jiang +7 more | Coatings

Residual particles embedded at the bond coat/substrate (BC/SUB) interface after grit blasting can affect the failure behavior of thermal barrier coatings (TBCs) under thermal cycling. This study employed a 2D … Residual particles embedded at the bond coat/substrate (BC/SUB) interface after grit blasting can affect the failure behavior of thermal barrier coatings (TBCs) under thermal cycling. This study employed a 2D finite element model combining the cohesive zone method (CZM) and extended finite element method (XFEM) to analyze the effect of interfacial grit particles. Specifically, the CZM was used to simulate crack propagation at the BC/thermally grown oxide (TGO) interface, while XFEM was applied to model the arbitrary crack propagation within the BC layer. Three models were analyzed: no grit inclusion, 20 μm grit particles, and 50 μm grit particles at the BC/SUB interface. This systematic variation allowed isolating the influence of particle size on the location of crack propagation onset, stress distribution, and crack growth behavior. The results showed that grit particles at the SUB/BC interface had negligible influence on the crack propagation location and rate at the BC/TGO interface, due to their spatial separation. However, their presence significantly altered the radial tensile stress distribution within the BC layer. Larger grit particles induced more intense stress concentrations and promoted earlier and more extensive vertical crack propagation within the BC. However, due to plastic deformation and stress redistribution in the BC, the crack propagation was progressively suppressed in the later stages of thermal cycling. Overall, grit particles primarily promoted vertical crack propagation within the BC layer. Optimizing grit blasting to control grit particle size is crucial for improving the durability of TBCs.

Performance Improvement of Tin-Based Babbitt Alloy Through Control of Microstructure

2025-06-20

Wei Zhang , Hongxiang Shu , Gaixiao Qiao +3 more | Alloys

Babbitt alloys are among the most commonly used materials for sliding bearings. However, with the high speeds and heavy loads of modern machinery, as well as the demands of extreme … Babbitt alloys are among the most commonly used materials for sliding bearings. However, with the high speeds and heavy loads of modern machinery, as well as the demands of extreme working conditions, the temperature resistance, strength, and hardness of traditional Babbitt alloys are often insufficient to meet these requirements. To address this issue, it is essential to improve the properties of Babbitt alloys, particularly their performance at high temperatures. The present study explored a technical approach for incorporating copper powder to improve the high-temperature performance of Babbitt alloys. Copper powder was added to the traditional Babbitt alloy in mass percentages of 1, 2, 3, and 4%. After fabrication, the samples were examined using metallographic structure analysis, high-temperature compression testing, and friction and wear testing. The experiments investigated the effects of copper powder addition on the properties of the Babbitt alloy and determined the optimal amount of copper powder required to enhance its performance.

Effects of surface thermal spray coating on mechanical properties of STD11 steel

2025-06-20

JunHyouk Ar , Jei‐Pil Wang | International Journal of Innovative Research and Scientific Studies

This study aimed to increase wear resistance by forming a thermal spray coating layer on the steel surface using a high-hardness coating material. After quenching at 1030°C and low-temperature tempering … This study aimed to increase wear resistance by forming a thermal spray coating layer on the steel surface using a high-hardness coating material. After quenching at 1030°C and low-temperature tempering at 170°C on the existing STD11 steel, HVOF thermal spray of WC-12Co powder, surface fusing treatment using 60W-40Ni self-fluxing alloy powder, and arc wire thermal spray using Fe-29%Cr wire were performed to form a high-hardness coating layer on the surface of the STD11 steel. The surface of the manufactured sample was measured five times using a Vickers hardness (HV) tester, and the HVOF thermal spray was measured to be HRC70.6, the fusing thermal spray HRC64.2, and the arc wire thermal spray HRC62.9. The cross-section of each thermal spray coating layer was analyzed by SEM-EDX (Scanning Electron Microscopy-Energy Dispersive X-ray Analysis).

Predictive Modeling of Porosity in Al₂O₃–TiO₂ Ceramic Coatings Produced by Plasma Spraying

2025-06-20

Duong Vu , Ha Minh Hung | SPEKTA (Jurnal Pengabdian Kepada Masyarakat Teknologi dan Aplikasi)

Background: Plasma spraying is a proven technique for applying ceramic coatings to enhance the mechanical and chemical resistance of components exposed to abrasive and corrosive environments. However, controlling coating porosity … Background: Plasma spraying is a proven technique for applying ceramic coatings to enhance the mechanical and chemical resistance of components exposed to abrasive and corrosive environments. However, controlling coating porosity remains a critical factor that directly affects the coating's performance and lifespan. Contribution: This study contributes to the field by developing a predictive model that quantifies the influence of key plasma spraying parameters on the porosity of Al₂O₃–TiO₂ coatings. The model enables process optimization and quality control for applications requiring high-performance surface protection. Method: An orthogonal experimental design (N27) was implemented to systematically vary three process parameters: spray distance (Lp), plasma current intensity (Ip), and powder feed rate (Gp). A total of 27 coating samples were produced and analyzed. Results: The resulting porosity ranged from 5.96% to 14.52% depending on parameter combinations. The developed second-order polynomial regression model demonstrated good predictive accuracy, with deviation between measured and predicted values ranging from −8.67% to +13.96%, and typically within acceptable engineering limits. Conclusion: The findings confirm that process parameters significantly affect coating porosity, and that the proposed model is a useful tool for optimizing plasma spray operations.

Mechanical behavior of structural steel clad by wire arc thermal spraying

2025-06-20

Eitaro Horisawa , Masahide Matsumura , Risa Matsumoto +3 more | Journal of Constructional Steel Research

Numerical and Experimental Investigation of Thermal Barrier Effects of CNT-Reinforced Fly Ash/Alumina Coatings in Diesel Engine Pistons

2025-06-19

Nagarjuna Chavana , B. Sarkar , Sudhakar C. Jambagi | ACS Applied Materials & Interfaces

Fly ash (FA), an industrial byproduct from coal combustion, presents significant disposal challenges, especially in developing nations. Given its mineralogical properties, FA shows potential in thermal spray coatings. This study … Fly ash (FA), an industrial byproduct from coal combustion, presents significant disposal challenges, especially in developing nations. Given its mineralogical properties, FA shows potential in thermal spray coatings. This study evaluates FA-based coatings for pistons to improve thermal management in internal combustion engines through numerical simulations, analyzing their effects on the temperature distribution, thermal stress, and combustion efficiency. FA coatings were also applied to marine-grade steel with additives (50 wt % Al2O3 and 0-2 wt % CNT) to assess high-temperature performance. Microstructural analysis revealed that 2 wt % CNT-reinforced (2CAF) coatings showed agglomeration, reducing microhardness by ∼9.27% compared to 1 wt % CNT-reinforced (1CAF) coatings. The XRD analysis of 1CAF indicated ∼56.51% transformation of corundum to γ-alumina, lowering thermal conductivity by ∼15.40% compared to alumina/FA (AF) coatings, while 2CAF coatings showed increased conductivity due to CNT inhomogeneity. For piston applications, simulations showed an ∼24.59% rise in maximum surface temperature, from 241.39 to 300.76 °C, and an ∼62.06% reduction in heat flux, indicating enhanced durability and reduced cold-start emissions. Thermal cycling demonstrated that 1CAF coatings outlasted AF and 2CAF, suggesting FA-based TBCs as sustainable and economical options for enhanced engine performance and waste valorization.

Surface Orientation-Dependent Corrosion Behavior of NiCr Alloys in Molten FLiNaK Salt

2025-06-19

Hamdy Arkoub , D R Flynn , Adri C. T. van Duin +1 more | ACS Applied Materials & Interfaces

The corrosion behavior of NiCr alloys in molten FLiNaK salt is governed by complex Cr-F chemical interactions, necessitating a fundamental understanding for enhancing alloy performance in harsh environments. However, significant … The corrosion behavior of NiCr alloys in molten FLiNaK salt is governed by complex Cr-F chemical interactions, necessitating a fundamental understanding for enhancing alloy performance in harsh environments. However, significant gaps remain in our understanding of the dynamic atomic-scale processes driving the progression of molten salt corrosion. This study employs reactive force field-based molecular dynamics simulations to unravel the influence of crystallographic orientation, temperature, and external electric fields on corrosion kinetics. The (100), (110), and (111) orientations of Ni0.75Cr0.25 alloys are evaluated at temperatures from 600 to 800 °C, with and without electric fields. Results reveal that Cr dissolution and near-surface diffusion drive pitting-like surface morphology evolution. The (110) surface shows the highest corrosion susceptibility, while the (100) and (111) surfaces exhibit greater resistance, with (111) being the most stable. The corrosion activation energy, derived from the Arrhenius relation, ranges from 0.27 to 0.41 eV, aligning well with limited experimental data yet significantly lower than bulk diffusion barriers. This finding indicates that corrosion progression is primarily a kinetically controlled near-surface process, rather than being limited by bulk diffusion as suggested in previous understanding. Additionally, electric fields perpendicular to the interface are found to asymmetrically modulate corrosion dynamics, where a positive field (+0.10 V/Å) promotes Cr dissolution. In comparison, a negative field (-0.10 V/Å) largely suppresses corrosion, which can be effectively used to mitigate corrosion. These findings, along with atomistic details into the corrosion mechanisms, offer strategic perspectives for designing corrosion-resistant materials in advanced high-temperature molten salt applications.

Mechanical anisotropy and deposition mechanism of AA2024 prepared via cold spraying with different trajectories

2025-06-19

Jingxiao Zhang , Lixin Wang , Liang Chen +3 more | Journal of Manufacturing Processes

Influence of pre-oxidation on high temperature corrosion of laser directed energy deposited Ni-Cr-Mo alloy layer in KCl-NaCl salts

2025-06-19

Yao Kong , Huaqing Ning , Yue Shen +5 more | Materials Today Communications

Cold Spraying Remanufacturing Repair of Carbon Fiber-Reinforced Polyether Ether Ketone Composites

2025-06-19

Huanbo Cheng , He Zhai , Lijun Guo +2 more | Journal of Thermal Spray Technology

Effect of β-NiAl addition on the high temperature oxidation behaviour of thermally sprayed CoNiCrAlY coatings

2025-06-18

Hao Chen , Wei Luo | Journal of Materials Research and Technology

Effect of stress on hot corrosion behavior of CVD aluminide coatings on Mar-M247 superalloy in the environment of humid air-Na2SO4-NaCl

2025-06-18

Hu Qi , Shujiang Geng , Jinlong Wang +4 more | Surface and Coatings Technology

Microstructure and texture evolution of the oxide scale on hot rolled corrosion-resistant steel

2025-06-18

Chao Wang , Huibin Wu , Youyou Zhang | Journal of Materials Research and Technology

Corrosion behavior of micro-arc oxidation coatings modified by laser remelting on 6063 aluminum alloy

2025-06-18

Chao Wang , Yanfeng Ge , Bo Jiang +1 more | Materials Letters

Enhancing high-temperature phase stability and thermal properties of 5RE(TaxNb1-x)O4 high-entropy ceramics through chemical bonding strength optimization

2025-06-17

Mengdi Gan , Liping Lai , Xiaoyu Chong +7 more | Chemical Engineering Journal

Multi-Scale Modelling of Residual Stress on Arbitrary Substrate Geometry in Atmospheric Plasma Spray Process

2025-06-17

Jose Martínez-García , Venancio Martínez-García , Andreas Killinger | Coatings

This work presents an exhaustive parametric study of the multi-scale residual stress analysis on arbitrary substrate geometry based on a one-way-coupled thermo-mechanical model in an Atmospheric Plasma Spray process. It … This work presents an exhaustive parametric study of the multi-scale residual stress analysis on arbitrary substrate geometry based on a one-way-coupled thermo-mechanical model in an Atmospheric Plasma Spray process. It was carried out by modifying key process parameters, such as substrate surface geometry, substrate pre-heating temperature, and coating thickness, in an Al2O3 coating process on an aluminium substrate. The relationship of these parameters to the generation of quenching stress, thermal stress and residual stress was analysed at three different sub-modelling scales, from the macroscopic dimension of the substrate to the microscopic dimension of the splats. The thermo-mechanical phenomena occurring during the deposition process at the microscopic level were discussed in the proposed cases. Understanding these phenomena helps to optimise the parameters of the coating process by identifying the underlying mechanisms responsible for the generation of residual stresses. The simulated residual stresses of the 200 μm Al2O3 outer coated aluminium cylinder were experimental validated using the incremental high-speed micro-hole drilling and milling method.

Insights Into the Arrangement of Main Working Gas and Powder Carrier Gas on Gas–Particle Flow Dynamics in Cold Spraying

2025-06-17

Wenpeng Wan , Chunjie Huang , Jie Luo +3 more | Journal of Thermal Spray Technology

Corrosion Behavior of 304LN Stainless Steel in High-Temperature Supercritical Carbon Dioxide: Oxidation and Carburization

2025-06-16

Nanfu Li , Bin Wu , Jiazhen Wang +6 more | Acta Metallurgica Sinica (English Letters)

Deformation Mechanisms and Predictive Modeling of AlCoCrFeNi HEA under Hot Working Conditions

2025-06-14

Saurabh Vashistha , Bashista Kumar Mahanta , Pankaj Rawat +3 more | Journal of Alloys and Compounds

Microstructure and Tensile Properties of Cu-Ti Composites Deposited by Cold Spray Additive Manufacturing

2025-06-13

Jia Cheng , Jibo Huang , Haifan Li +4 more | Materials

In this study, copper–titanium (Cu-Ti) composite coatings with 6 wt.% titanium content were fabricated via cold spray additive manufacturing (CSAM) using nitrogen as the propellant gas. The synergistic effects of … In this study, copper–titanium (Cu-Ti) composite coatings with 6 wt.% titanium content were fabricated via cold spray additive manufacturing (CSAM) using nitrogen as the propellant gas. The synergistic effects of propellant gas temperatures (600 °C, 700 °C, 800 °C) and post-heat treatment temperatures (350 °C, 380 °C, 400 °C) on the microstructure and tensile properties were systematically investigated. Tensile testing, microhardness characterization, and fractography analysis revealed that increasing the propellant gas temperature significantly enhanced the plastic deformation of copper particles, leading to simultaneous improvements in deposit density and interfacial bonding strength. The as-sprayed specimen prepared at 800 °C propellant gas temperature exhibited a tensile strength of 338 MPa, representing a 69% increase over the 600 °C specimen. Post-heat treatment effectively eliminated the work-hardening effects induced by cold spraying, with the 400 °C treated material achieving an elongation of 15% while maintaining tensile strength above 270 MPa. Microstructural analysis demonstrated that high propellant gas temperatures (800 °C) promoted the formation of dense lamellar stacking structures in copper particles, which, combined with a recrystallized fine-grained microstructure induced by 400 °C heat treatment, enabled synergistic optimization of strength and ductility. This work provides critical experimental insights for process optimization in CSAM-fabricated Cu-Ti composites.

Investigating CMAS corrosion in ultrahigh temperature Hf6Ta2O17‐based thermal barrier coatings: A mechanism by which corrosion products hinder corrosion resistance

2025-06-11

Qiaozhen Zhou , Qianwen Wang , Yang Li +1 more | Materials Genome Engineering Advances

Abstract Hf 6 Ta 2 O 17 ceramic has outstanding thermal and mechanical properties, along with an extremely high phase transition temperature (2517 K), making it a promising candidate for … Abstract Hf 6 Ta 2 O 17 ceramic has outstanding thermal and mechanical properties, along with an extremely high phase transition temperature (2517 K), making it a promising candidate for next‐generation thermal barrier coatings (TBCs). High‐temperature corrosion of TBCs by calcium‐magnesium‐alumino‐silicates (CMAS) is a major failure mode. To understand why Hf 6 Ta 2 O 17 ceramic resists CMAS corrosion well at high temperatures, the CMAS/Hf 6 Ta 2 O 17 (010) system was analyzed via density functional theory to study CMAS – induced corrosion processes. Results show that above 1523 K, the diffusion coefficient of atoms in CMAS exceeds that in Hf 6 Ta 2 O 17 (010). Also, there is significant mutual diffusion between (Ca, Si) and (Hf, Ta) with a low diffusion activation energy. The interaction between CMAS and Hf 6 Ta 2 O 17 has a low reaction energy, enabling the quick formation of dense corrosion products (CaTa 2 O 6 and HfSiO 4 ) at the interface. These products have high phase stability and fast formation rates, remaining intact when in contact with residual CMAS. The interface‐formed corrosion products greatly reduce the CMAS diffusion coefficient into Hf 6 Ta 2 O 17 ; for instance, calcium, the fastest‐diffusing element, has its diffusion coefficient reduced by over five times. These mechanisms effectively limit CMAS corrosion of Hf 6 Ta 2 O 17 , enhancing its potential as an ultrahigh temperature TBCs for the next generation.

Synergistic Corrosion Mechanisms of Alloys in High‐Temperature and High‐Pressure Water Environments: A Review

2025-06-06

Huan Liu | Materials and Corrosion

ABSTRACT High‐temperature and high‐pressure (HTHP) water serves as a critical heat‐exchange and reaction medium in numerous industrial applications. Under these extreme conditions, water exhibits distinct physicochemical properties that significantly elevate … ABSTRACT High‐temperature and high‐pressure (HTHP) water serves as a critical heat‐exchange and reaction medium in numerous industrial applications. Under these extreme conditions, water exhibits distinct physicochemical properties that significantly elevate the corrosion susceptibility of alloys. This study investigates the mechanisms of oxidative corrosion, electrochemical corrosion, and stress corrosion cracking (SCC) in alloys exposed to HTHP water. From a synergistic perspective, it elucidates how interconnected phenomena—namely, accelerated oxide layer rupture, enhanced ion diffusion, and localized stress concentration—markedly accelerate alloy degradation. The findings reveal that reduced intermolecular hydrogen bonding, increased electrical conductivity, and heightened activity of corrosive ions in HTHP water are critical drivers of corrosion. By analyzing molecular structures and dynamics, it clarifies the complex interplay among HTHP water properties, corrosive ions, electrochemical reactions, and mechanical stress, thereby enhancing the understanding of alloy failure mechanisms. These insights provide a theoretical basis for designing corrosion‐resistant materials and equipment.