Ti6al4v the importance of the grain size of powder for spraying in shaping the utilitarian properties of wccocr supersonic sprayed on alloy ti6al4v

The paper tests the influence of grain size in powder for heat spraying on the structure and chosen properties of coatings type WCCoCr supersonic sprayed on titanium alloy Ti6Al4V. It was shown in the paper that application of fine-grained powder for spraying with grain size of 15μm enables achievement of good quality layers without crackings and discontinuities with proper connection with metallic basis. Microstructure tests with application of scanning electron microscopy have shown that the coatings sprayed with the use of fine powder have very low porosity (0.2%) and are characterised with big homogeneity of chemical composition. Moreover, they have high hardness of 1221 HV0.3 with low value of standard deviation which equals 33. Such coatings are characterised with very good tightness and, in comparison with coatings sprayed with powder with standard grain size (45 μm), have better corrosion resistance in 3.5% solution of NaCl.