Study On The Performance Of Coating Prepared By Laser Surface Alloying On 1Cr18Ni9Ti Stainless Steel

The TiC reinforced composite coating was produced on 1Cr18Ni9Ti austenitic stainless steel by laser surface alloying. The phase, microstructure, microhardness and wear resistance of the laser surface alloying coatings were investigated by X'pert MPD X-ray diffraction meter, MBS optical microscopy, Philips XL30 scanning electron microscopy, HXD-1000 microhardness tester and MM-200 sliding wear tester. The effects of stabilizing treatment on the microstructure and character of the laser surface alloying coatings have been discussed in this paper.Analysis and tests indicate that the main phases of the laser surface alloying coating consist of Austenitic, TiC and Cr23C6.The microstructure of laser surface alloying coating is fine, without pores, cracks or other defects. The laser surface alloying coating is metallurgically bonded to the 1Cr18Ni9Ti stainless steel substrate. TiC particles distribute in alloying coating uniformly in the form of irregular block and petal. TiC particles grow a bit bigger and look roundish after stabilizing treatment.The microhardness of the laser surface alloying coating is up to 427.6 HV, which is about twice of that of the substrate, and the numbers of microhardness is a gradient distribution along the depth of the laser surface alloying. The microhardness of laser surface alloying coating and the substrate is slightly lower than that before stabilizing treatment, but the bonding strength between laser surface alloying coating and substrate is highly improved.At room temperature and in oil lubrication condition, the sliding wear test results reveal that the maximum average friction coefficient of laser surface alloying is 0.01219, which is much less than that of corresponding substrate. And the maximum weight loss of the laser surface alloying coating is 0.1436g, less than that of corresponding substrate which is 0.3205g.There are no grooves or crater on the worn surface of the laser surface alloying coating. After stabilizing treatment the friction coefficient and weight loss of the laser surface alloying coating and the substrate are smaller than those before, and the worn surfaces of the laser surface alloying coating are much smoother than those before in the same condition, demonstrating excellent wear resistance. The stabilizing treatment can improve the comprehensive performance of the laser surface alloying coating effectively.