Structure, Phase Composition, and Wear Mechanisms of Plasma-Sprayed NiCrSiB-20 wt.% TiB.sub.2 Coating

• Published in: Powder metallurgy and metal ceramics Vol. 53; no. 11-12; p. 663
• Main Authors: Umanskii, A. P, Storozhenko, M. S, Hussainova, I. V, Terentiev, A. E, Kovalchenko, A. M, Antonov, M. M
• Format: Journal Article
• Language: English
• Published: Springer 01.03.2015
• Subjects: Coatings; Powders (Particulate matter); Titanium
• ISSN: 1068-1302; 1573-9066
• DOI: 10.1007/s11106-015-9661-3

The structure, phase composition, and wear mechanisms of plasma-sprayed NKhTB20 coating (NiCrSiB-20 wt.% TiB.sub.2) are studied. To produce NKhTB20 composite powder, commercial PR-NKh16SR3 (NiCrSiB) powder was mixed with 20 wt.% TiB.sub.2 and the charge was pressed and sintered in vacuum at 1100°C for 30 min. During sintering, the components react to form chromium borides. The sinters were ground and classified into the particle size fraction -100+60 nm for plasma spraying. The plasma-sprayed NKhTB20 coating consists of a nickel-based matrix reinforced with titanium diboride and chromium boride grains. The friction and wear behavior of the NKhTB20 coating in dry friction against plasma-sprayed NiCrSiB and NKhTB20 coatings is examined. It is revealed that the NKhTB20/NiCrSiB friction pair has higher wear resistance than NKhTB20/NKhTB20. The contact surfaces of the NKhTB20/NKhTB20 friction pair are damaged under oxidative and abrasive wear mechanisms. Oxidative wear is the dominant mechanism for the NKhTB20/NiCrSiB friction surface. Complex oxide films form on the NKhTB20/NiCrSiB sliding surface and prevent it from damage.