Abstract:
Two types of Ni45/Cr
3C
2/nickel-coated MoS
2 composite coatings with different Cr
3 C
2 contents were fabricated on the surface of 300M steel using laser cladding technology. The results indicate that with an increase in Cr
3 C
2 content, the intergranular Cr
xC
ystructures in the coatings transition from fine spherical and rod-like particles to elongated structures. Due to the flotation of hard phase particles, grain refinement, and the formation of intergranular secondary Cr
xC
y phases, the surface hardness of the coating with 6%Cr
3 C
2 reaches 511 HV0.5 and the average hardness is 520.43 HV0.5, while the coating with 9%Cr
3 C
2 exhibits a surface hardness of 633 HV0.5 and an average hardness of 599.42 HV0.5. Both composite coatings show a hardness increase of over 370 HV0.5 compared to the 300M steel substrate. The synergistic effect of sulfides such as MoS
2,Cr
xS
y, Ni S, partially dissolved Cr
3 C
2 particles, and secondary Cr
xC
y hard phase particles result in an average friction coefficient of 0.39736 for the coating with 6%Cr
3 C
2 and 0.34104 for the coating with 9%Cr
3C
2. At room temperature, the wear rate of the coating with 6%Cr
3 C
2 is 1.41388×10
-5mm
3/(N·m), slightly higher than 1.19249×10
-5mm
3/(N·m) of the coating with 9%Cr
3C
2.The primary wear mechanisms for both coatings are identified as mild abrasive wear and oxidative wear.