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

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

Thermal spray coatings for molten salt facing structural parts and enabling opportunities for thermochemical cycle electrolysis

“…By careful design of thermal spray process, for example, selection of geometry, particle shape and size, crystal structure and arrangement, one can tailor surface properties (including adding corrosion resistant functionality for thermochemical cycle structural parts) without significant surface preparation of the material. If one needs to obtain selective coating properties (including residual strain which is inherent to such thermal spray coatings 57 ), there can be many variations possible with functional features aligned to have reduced degradation of coatings.…”

Application of Thermal Spray Coatings in Electrolysers for Hydrogen Production: Advances, Challenges, and Opportunities

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Numerical research on Inconel718 laser additive repairing

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