Abstract
New fabrication technique of multilayered composite coatings on inner surface of pipes is developed which is based on ion–plasma sputtering of rod–like target composed of various metals and graphite. It is established that gradient change of elemental composition in the direction Сr→W→Mo→Ta→Hf→Ti→C→Ti/Al→C is accompanied by transition from metal mixture carbide to titanium carbide with the grain sizes of ~ 8–15 nm. It is found that increase in microhardness up to ~ 26 GPa is caused by additional surface heating by thermal radiation from the ion–heated rod and by elemental composition of the composite layers.
Highlights
Functional capabilities of protective coatings used under complex of unfavourable factors are determined by the related physical properties
Their efficiency is explained by capability of different interlayers of a composite to support high adhesion combined with high antifriction characteristics while maintaining proper level of microhardness, strength and resistance to various external impacts of the coatings
The following can be concluded: 1. The indicated above gradient variation of elemental composition of the coatings creates prerequisites for high adhesion at the interface between the substrate and the Cr–enriched interlayers
Summary
Functional capabilities of protective coatings used under complex of unfavourable factors are determined by the related physical properties The latter include a group of such characteristics as adhesion, microhardness, heat resistance, fracture strength, corrosion resistance, tribological durability, radiation resistance, etc. That is why there is a modern trend in development of ion–plasma technologies which is based on formation of multilayered and multicomponent coatings at the same time [1,2,3,4,5] Their efficiency is explained by capability of different interlayers of a composite to support high adhesion combined with high antifriction characteristics while maintaining proper level of microhardness, strength and resistance to various external impacts of the coatings. At the same time in order to avoid cleavage and cracking of the coatings, it is necessary to secure decrease and delocalization of intrinsic mechanical stress
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