Effect of Kerosene Flow on Microstructure and High Temperature Wear Properties of NiCrBSi-CrSi2 Coating
The NiCrBSi-CrSi2 composite coating was prepared by supersonic flame spraying(HVOF)technology on the 12CrMoVG substrate at different kerosene flow rates.The coating phase,microstructure,mechanical properties and high temperature friction and wear properties were characterized by XRD,SEM,EDS,Raman,Vickers microhardness tester,electronic tensile testing machine and high temperature rotational friction and wear testing machine at different kerosene flow rates.The results show that the phase composition of coatings is basically the same,all of which have y-Ni,Ni3B,Cr2B,CrSi2 and Cr5Si3.But as the kerosene flow increases,the CrSi2 and Cr2B parts in the coating will be transformed into Cr5Si3 and CrB phases,respectively.The microhardness and bonding strength of the coating show a trend of first increasing and then decreasing with the increase in kerosene flow,and the porosity and wear rate show a trend of first decreasing and then increasing.When the kerosene flow rate is 30 L/h,the powder melting effect is the best,the porosity of the coating is the lowest of 0.17％,the microhardness(HV0.3)is the highest of 5576.2 MPa,the bonding strength is the highest of 59 MPa,and the wear rate is the lowest of 2.84×10-14 m3·(N·m)-1.Oxides such as Cr2O3,SiO2 and NiCr2O4 generated on the surface of the wear mark and the high coating hardness make the coating at the kerosene flow rate of 30 L/h show optimal high temperature friction and wear resistance.The wear mechanism of the coating is mainly oxidative wear and adhesive wear.
supersonic sprayingNiCrBSi-CrSi2 composite coatingkerosene flowmicrostructurehigh temperature wear performance
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