Dynamic Behaviour of Plasma Sprayed Ni and Ta

Plasma spraying is a coating technique which has found widespread use in the application of ceramic or metal coatings over large surface areas. These layers can supply thermal, corrosion and abrasion resistance, in addition to altering the surface finish and appearance. Depending on the nature of the component, these coatings may experience impact or blast loading, during which the properties of the outer coating can modify the shock transmitted to the inner layers. In this study a series of plate impact experiments were conducted on samples of plasma sprayed Ni and Ta to evaluate the behaviour of these materials when shocked. The materials were characterised pre-shot to better understand the microstructure generated by the plasma spraying process, which proved to be highly anisotropic with some residual porosity. The samples were fielded alongside conventional Ni or Ta to provide a direct comparison under identical loading conditions, and were diagnosed with rear surface velocimetry to supply velocity-time records. Analysis of this data revealed significant differences between the conventional and plasma sprayed material under shock loading. Subsequent post-shock investigations also provided insight into the influence of the porous structure on the damage and failure mechanisms.

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