Microstructure and Properties of Laser Cladding Stellite 12/TiC/CaF₂ Composite Coating on Copper Substrate

Abstract

Stellite 12/TiC/CaF2 composite coating has been successfully fabricated on copper substrate by a pulsed Nd:YAG laser system with preplacment powder bed to improve the absorbance of copper substrate to laser energy. Microstructures, phases and wear properties were studied by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), dry sliding wear tester. The results showed that the existence phases of Co-based solid solution, Cr4Ni15W, TiC, Cr23C6, CaF2 and Ti8C5. The morphology of titanium carbide is mainly spherical and exists in two forms, one is TiC and the other is Ti8C5. The microhardness of the layers reveals a gradient variation along the cross section of the LSA layers. The friction coefficient of the coating is oscillating around approximately 0.17 because CaF2 is a solid lubricant because of the lamellar structure and softness and Titanium carbide is hard. The dry sliding wear testing shows the wear resistance of as-receive copper is significantly improved by laser cladding Stellite 12/TiC/CaF2 composite coating.

Stellite-6/(WC+TiC) Composite Coatings Produced by Laser Alloying on S355 Steel

“…This alloy is characterized by high corrosion resistance, friction wear resistance, and good properties at elevated temperatures; however, its wear resistance and hardness in demanding applications may not be satisfactory. One way to improve these properties is to add high hardness and wear resistance particles such as tungsten [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ] and titanium [ 19 , 20 , 21 , 22 , 23 ] carbides to the powder and others [ 24 , 25 , 26 ]. As a result of remelting the mixture of these materials, a composite layer can be obtained in which carbides are reinforcing particles distributed in the alloy matrix.…”