Investigation into the Effects of High Temperature on Mechanical Properties of Thermal Spray Coatings Applied by Plasma Spraying

C. C. Berndt advanced investigations of mechanical properties of thermal spray coatings under 4-point bending. He found that this investigation method is sensitive to the mechanical properties of thermal spray coatings.This paper contains the detailed investigation results for thermal spray coatings of zirconium dioxide under 4-point bending, i.e. tests of the specimens subjected to spraying at varying conditions and pre-test soaking with the various duration at 1100 °С.It was established how the mechanical properties of thermal spray coatings changed depending on the spraying mode and high temperature soaking. The test results show that the double heat treatment of coatings is more preferable than one-time heat treatment as it make the properties change linearly. It is more easily controllable during operation of the components with thermal spray coating.

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Measuring residual strain and stress in thermal spray coatings using neutron diffractometers

10.21203/rs.3.rs-375306/v1 ◽

2021 ◽

Author(s):

Nadimul Haque Faisal ◽

Rehan Ahmed ◽

Anil K Prathuru ◽

Anna Paradowska ◽

Tung Lik Lee

Keyword(s):

Neutron Diffraction ◽

Diffraction Analysis ◽

Thermal Spray ◽

Residual Strain ◽

Spray Coating ◽

Thermal Spray Coating ◽

Thermal Spray Coatings ◽

Neutron Sources ◽

Neutron Diffraction Analysis ◽

Spray Coatings

Abstract Background: During thermal spray coating, residual strain is formed within the coating and substrates due to thermo-mechanical processes and microstructural phase changes. Objective: This paper provides a comprehensive guide to researchers planning to use neutron diffraction technique for thermal spray coatings, and reviews some of these studies. Methods: ENGIN-X at the ISIS spallation source is a neutron diffractometer (time-of-flight) dedicated to materials science and engineering with high resolution testing. The focus is on the procedure of using ENGIN-X diffractometer for thermal spray coatings with a view that it can potentially be translated to other diffractometers. Results: Number of studies involving neutron diffraction analysis in thermal spray coatings remain limited, partly due to limited number of such strain measurement facilities globally, and partly due to difficulty is applying neutron diffraction analysis to measure residual strain in the thermal spray coating microstructure. Conclusions: This technique can provide a non-destructive through-thickness residual strain analysis in thermally sprayed components with a level of detail not normally achievable by other techniques. Neutron sources have been used to measure strains in thermal spray coatings, and here, we present examples where such coatings have been characterised at various neutron sources worldwide, to study residual strains and microstructures.

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Advanced thermal spray coatings for tribological applications

Proceedings of the Institution of Mechanical Engineers Part L Journal of Materials Design and Applications ◽

10.1243/14644207jmda135 ◽

2007 ◽

Vol 221 (3) ◽

pp. 175-185 ◽

Cited By ~ 5

Author(s):

C Bartuli ◽

T Valente ◽

F Casadei ◽

M Tului

Keyword(s):

Thermal Spray ◽

Spray Coating ◽

Ceramic Coatings ◽

Thermal Spray Coating ◽

Thermal Spray Coatings ◽

Solid Lubrication ◽

Titanium Nitrides ◽

Spray Coatings ◽

Hybrid Techniques ◽

Wear Protection

Thermal spray coating is one of the most common procedures to improve the tribological properties of materials. Ceramic and cermet coatings, especially those based on oxides (alumina, chromium oxide, etc.) and carbides, are widely used for wear protection. Improvements under investigations are related to the possible use of nanostructured coatings and to the potential application of hybrid techniques. As a possible alternative, solid lubrication is proposed as integration or replacement of the traditional liquid lubrication in the case of severe operative conditions when there is the possibility of a lack of lubricant or when environmental problems can arise from waste disposal. In the present paper, results from experimental activities on different types of abrasion-resistant thermal spray coatings are presented: graded coating systems, specifically designed for titanium-based alloys, obtained by reactive plasma spraying and physical vapour deposition of titanium nitrides; nanostructured WC-Co coatings deposited by high velocity oxy-fuel; plasma-sprayed ceramic coatings based on oxides containing nanophases either from nanostructured precursors or postprecipitated by purposely designed thermal treatments; self-lubricant coatings deposited by plasma spray with the inclusion of graphite.

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Measuring Residual Strain and Stress in Thermal Spray Coatings Using Neutron Diffractometers

Experimental Mechanics ◽

10.1007/s11340-021-00803-9 ◽

2021 ◽

Author(s):

N. H. Faisal ◽

R. Ahmed ◽

A. K. Prathuru ◽

A. Paradowska ◽

T. L. Lee

Keyword(s):

Neutron Diffraction ◽

Diffraction Analysis ◽

Thermal Spray ◽

Residual Strain ◽

Spray Coating ◽

Thermal Spray Coating ◽

Thermal Spray Coatings ◽

Neutron Sources ◽

Neutron Diffraction Analysis ◽

Spray Coatings

Abstract Background During thermal spray coating, residual strain is formed within the coating and substrates due to thermo-mechanical processes and microstructural phase changes. Objective This paper provides a comprehensive guide to researchers planning to use neutron diffraction technique for thermal spray coatings, and reviews some of these studies. Methods ENGIN-X at the ISIS spallation source is a neutron diffractometer (time-of-flight) dedicated to materials science and engineering with high resolution testing. The focus is on the procedure of using ENGIN-X diffractometer for thermal spray coatings with a view that it can potentially be translated to other diffractometers. Results Number of studies involving neutron diffraction analysis in thermal spray coatings remain limited, partly due to limited number of such strain measurement facilities globally, and partly due to difficulty is applying neutron diffraction analysis to measure residual strain in the thermal spray coating microstructure. Conclusions This technique can provide a non-destructive through-thickness residual strain analysis in thermally sprayed components with a level of detail not normally achievable by other techniques. Neutron sources have been used to measure strains in thermal spray coatings, and here, we present examples where such coatings have been characterised at various neutron sources worldwide, to study residual strains and microstructures. Graphic Abstract

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Mechanical properties and microstructure of WC–10Co–4Cr and WC–12Co thermal spray coatings deposited by HVOF

Surface Engineering ◽

10.1179/174329408x326380 ◽

2008 ◽

Vol 24 (5) ◽

pp. 374-382 ◽

Cited By ~ 26

Author(s):

Y. Y. Santana ◽

La J. G. Barbera-Sosa ◽

J. Caro ◽

E. S. Puchi-Cabrera ◽

M. H. Staia

Keyword(s):

Mechanical Properties ◽

Thermal Spray ◽

Thermal Spray Coatings ◽

Spray Coatings

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Advances in Corrosion-Resistant Thermal Spray Coatings for Renewable Energy Power Plants: Part II—Effect of Environment and Outlook

Journal of Thermal Spray Technology ◽

10.1007/s11666-019-00939-0 ◽

2019 ◽

Vol 28 (8) ◽

pp. 1789-1850 ◽

Cited By ~ 4

Author(s):

Esmaeil Sadeghi ◽

Nicolaie Markocsan ◽

Shrikant Joshi

Keyword(s):

High Temperature ◽

Thermal Spray ◽

Power Plants ◽

High Temperature Corrosion ◽

Thermal Spray Coatings ◽

Current Status ◽

Comprehensive Overview ◽

Biomass Waste ◽

Corrosion Resistant ◽

Spray Coatings

Abstract High-temperature corrosion of critical components such as water walls and superheater tubes in biomass/waste-fired boilers is a major challenge. A dense and defect-free thermal spray coating has been shown to be promising to achieve a high electrical/thermal efficiency in power plants. The field of thermal spraying and quality of coatings have been progressively evolving; therefore, a critical assessment of our understanding of the efficacy of coatings in increasingly aggressive operating environments of the power plants can be highly educative. The effects of composition and microstructure on high-temperature corrosion behavior of the coatings were discussed in the first part of the review. The present paper that is the second part of the review covers the emerging research field of performance assessment of thermal spray coatings in harsh corrosion-prone environments and provides a comprehensive overview of the underlying high-temperature corrosion mechanisms that lead to the damage of exposed coatings. The application of contemporary analytical methods for better understanding of the behavior of corrosion-resistant coatings is also discussed. A discussion based on an exhaustive review of the literature provides an unbiased commentary on the advanced accomplishments and some outstanding issues in the field that warrant further research. An assessment of the current status of the field, the gaps in the scientific understanding, and the research needs for the expansion of thermal spray coatings for high-temperature corrosion applications is also provided.

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Image-Based Modeling for Assessing Thermal Conductivity of Thermal Spray Coatings at Ambient and High Temperature

Heat Transfer, Volume 2 ◽

10.1115/imece2006-15972 ◽

2006 ◽

Cited By ~ 1

Author(s):

Y. Tan ◽

A. Sharma ◽

J. P. Longtin ◽

S. Sampath ◽

H. Wang

Keyword(s):

Thermal Conductivity ◽

High Temperature ◽

Thermal Spray ◽

Process Parameters ◽

Thermal Spraying ◽

Thermal Spray Coatings ◽

Analysis Model ◽

Element Analysis ◽

Spray Coatings ◽

Coating Microstructure

Thermal spray coatings are used extensively for protection of engineering components and structures in a variety of applications. Due to the nature of thermal spraying process, the coating thermal, mechanical, and electrical properties depend strongly on the coating microstructure, which consists of many individual splats, interfaces between the splats, defects and voids. The coating microstructure, in turn, is determined by the thermal spray process parameters. In order to relate coating process parameters to the final coating performance, then, it is desirable to relate coating microstructure to coating properties. In this work, thermal conductivity is used as the physical parameter of interest. Thermal conductivity of thermal spray coatings is studied by using an image analysis-based approach of typical coating cross sections. Three coating systems, yttria stabilized zirconia (YSZ), molybdenum, and Ni-5wt.%Al are explored in this work. For each material, thermal conductivity is simulated by using a microstructure image-based finite element analysis model. The model is then applied to high temperature conditions (up to 1200 °C) with a hot stage-equipped scanning electron microscope imaging technique to assess thermal conductivity at high temperatures. The coating thermal conductivity of metallic coatings is also experimentally measured by using a high-temperature laser flash technique.

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A Contribution to Methodology and Protocol Definition for Thermal Spray Coated Surface Compatibility Analysis in Food Processing Applications

Thermal Spray 1998: Proceedings from the International Thermal Spray Conference ◽

10.31399/asm.cp.itsc1998p1019 ◽

1998 ◽

Author(s):

A. Scrivani ◽

N. Antolotti ◽

S. Bertini ◽

G. Viola ◽

R. Groppetti ◽

...

Keyword(s):

Thermal Spray ◽

Food Additives ◽

Spray Coating ◽

Thermal Spray Coating ◽

International Standards ◽

Test Case ◽

Testing Methodology ◽

Spray Coatings ◽

Temperature Conditions ◽

Compatibility Analysis

Abstract The paper discusses the testing methodology and identifies the analytical protocols, with proper validation, in order to evaluate the compatibility of thermal spray coatings in the food production technology, according to EU and FDA applicable standards. A brief state-of-the-art analysis of the international standards on food additives and human health is given, namely on indirect food additives (as defined in 21 CFR 170.3(e)), that can migrate into the food during the process. An outline of the test protocols, based on contact between coating and food simulating solvents in a set time/temperature conditions, are presented, and the main phases for the proposed testing methodology, as the choice of the simulating solvent, the migration cell design and the time/temperature conditions, are discussed. Finally the proposed methodology and protocols are validated through a thermal spray coating for food process application test case.

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Surface Analysis of Shear Strength Tested Tungsten Carbide Thermal Spray Coatings+

Microscopy and Microanalysis ◽

10.1017/s1431927600010849 ◽

1997 ◽

Vol 3 (S2) ◽

pp. 791-792 ◽

Cited By ~ 1

Author(s):

S. V. Naidu ◽

Carlos Green ◽

Christopher Maxie ◽

James D. Garber ◽

Gary A. Glass

Keyword(s):

Thermal Spray ◽

Adhesive Strength ◽

Shear Test ◽

Spray Coating ◽

Test Method ◽

Thermal Spray Coatings ◽

Oxide Content ◽

Ring Shear Test ◽

Spray Coatings ◽

Ring Shear

Thermal spray processing has become an important powder-consolidation technique to yield new materials for extremes of temperature, radiation, wear, corrosion and mechanical stresses. High Velocity Oxy-Fuel (HVOF) spray coating process gives higher deposition densities and coating hardness; lower oxide content and porosity. The adhesive strength of thermal spray coatings is greatly effected by the interfacial impurities. The ring shear test method shown in Fig. 1 appears to give the most accurate results on shear adhesive strength. A typical ring shear test result of 88WC12Co 1/4" ring HVOF thermal spray coating on 4140 steel rod using a Jet kote thermal spray gun is shown in Fig. 2. Repeated ring shear tests on similar samples prepared under same spray and test conditions resulted in different shear bond strength and coating ring displacement before break off. We examined the ring shear tested coatings using a Zeiss DMS942 Scanning Electron Microscope (SEM) and Kevex Energy Dispersive X-ray Spectrometer (EDXS) with LPX1 Quantum Si(Li) Detector.

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