TC4 Laser Cladding Ni60Ti 3Research On SiC 2 Self-lubricating Coatings

With the development of aerospace industry,titanium alloys have been widely used because of its own merits,such as low elastic modulus,high specific strength,excellent corrosion resistance.However,titanium alloys' s larger friction coefficient and poor wear resistance were limited its application range.Laser cladding can form a composite coating of high hardness and good wear resistance onto the surface of titanium and its alloys,to improve its surface defects effectively as well as maintain the matrix's good performance.Whereas with the continuous development of modem industry,not only need to improve the wear resistance of the coating,but also requires the coating with self-lubrication to satisfy where are difficult to use lubricating oil.Therefore,the development of new coating material system,so that the coating both abrasion and wear properties,has important application value.The phase of the composite coatings prepared by Ni60+Ti₃SiC2 is mainly composed of ?-Ni solid solution,TiNi/Ti₂ Ni biphasic intermetal lic compounds,TiC,TiB,TiB2,Ti₃SiC2.When the Ti₃SiC2 content is 10%,laser power P=3kW,scanning speed V=7mm/s,obtained the maximum microhardness of the cladding layer is about800¹050HV0.3,it is about 3 to 4 times than TC4 alloy's microhardness;at the same time,the minimum friction coefficient of 0.21⁰.28 and 0.31⁰.34 was achieved under both atmospheric and vacuum conditions with the lowest wear mass of 2.5 mg and 3.2 mg.The wear mechanisms were both adhesive and abrasive wear.Adding rare earth oxide material CeO₂ did not change the phase type of Ni60 +Ti₃SiC2 composite coatings.When the CeO₂ content is 1.5%,laser power P=2kW,scanning speed V=7mm/s,obtained the maximum microhardness of the cladding layer is about 1250-1550HV0.3;at the same time,the minimum friction coefficient of0.21-0.25 and 0.27⁰.35 was achieved under both atmospheric and vacuum conditions with the lowest wear mass of 1.7 mg and 1.9 mg.The rare earth oxide material CeO₂ has obvious grain refinement effect on the composite coating,greatly improving the hardness and wear resistance of the composite coating.