Plasma sprayed composite material NiCrSiB-TiB2 coatings tribotechnical characteristics

Abstract

The aim of the study is to investigate the tribotechnical characteristics of plasma sprayed NiCrSiB-based self-fluxing alloy with titanium diboride additives (10 wt.%, 20 wt.% and 40 wt.%) coatings. The tests were conducted under dry sliding conditions against plasma sprayed corundum (Al2O3) coating by technique “shaft – partial liner” at sliding speed of 6 m/s and constant load of 1 MPa. It has been determined that the heterogeneous structure of composite materials coatings provides the high wear re-sistance of friction couples “plasma sprayed NiCrSiB-based coating with TiB2 additives (10 wt.%, 20 wt.% and 40 wt.%) - plasma sprayed Al2O3 coating”, as the previously investigated couples “NiCrSiB-based coating with TiB2 additives (10 wt.%, 20 wt.% and 40 wt.%) – Steel 15”, because of composite material reinforcement phases hardness (10,7 - 25,4 GPa). The best tribotechnical characteristics were shown by the couple “NiCrSiB-TiB2 (20 wt.%) - Al2O3 (linear wear – 8,5µm/km, fmp – 0,3). In all investigated couples, such as “NiCrSiB-TiB2 (10 wt.%, 20 wt.% and 40 wt.%) - Al2O3” the wear rate is less than in couple “NiCrSiB-TiB2 (20 wt.%) – Steel 15”. It has been determined that the addition of titanium diboride from 10 wt.% - 40 wt.% into the NiCrSiB alloy results in increasing of coatings wear resistance. The wear of counter body of corundum coating in couple “NiCrSiB-TiB2 (10 wt.%, 20 wt.% and 40 wt.%) - Al2O3” is proved to be dominated over the composite material wear, in contrast with the couple “NiCrSiB-TiB2 (20 wt.%) – Steel 15”. This fact must be taken into account when developing the friction units of the considered materials. Increasing of adhesion bond of particles in coatings by using the high-velocity methods of spraying, such as deto-nation and HVOF methods is the promising way of increasing the wear resistance of couples “NiCrSiB-TiB2 (10 wt.%, 20 wt.% and 40 wt.%) - Al2O3”.