Microstructure And Properties Of Plasma Clad Ti₅Si₃Reinforced Wear Resistant Intermetallic Composite Coatings

Titanium alloy is widely used in aviation, aerospace, petrochemical, shipbuilding and other industries with excellent performance characteristics as small density, specific strength, high specific stiffness, corrosion resistance and so on.However, the titanium alloy has many disadvantages like high coefficient of friction, easy adhesion, low wear resistance, difficult to lubrication which severely limits its application as friction pair moving parts.In view of that situation, this paper presents surface peening of titanium alloy by DC plasma beam cladding technology, in order to improve the hardness, wear resistance and corrosion resistance.With high purity argon was selected as the working and protection gas, Ti-43Si-19Ni-38(wt.%), Ti-39Si-16Ni-45(wt.%) and Ti-28Si-13Ni-59(wt.%) mixed alloy powder as raw material, we prepared the intermetallic Composite coatings the intermetallic NiTi2as the matrix, the main phase containing different volume fractions of refractory metal silicide Ti5Si3as the primary phase on BT9titanium alloy substrate by DC plasma beam cladding technology.This paper has analyzed the phase composition and microstructure of the Plasma Clad Ti5Si3reinforced wear resistant intermetallic Composite coatings by using optical microscope(OM), scanning electron microscope(SEM), X ray diffraction(XRD),Energy Dispersive Spectrometer(EDS) and tested the hardness gradient distribution of the coating. The results shows that:the coating is dense, uniform and fine, with a good metallurgical bonding between coating and substrate; The hardness of the coating increased significantly compared to the substrate, and the higher the volume fraction of reinforcing phase Ti5Si3, the higher coating hardness will be.Dry sliding friction and wear characteristics test at room temperature has been conducted,and the result showes that the Plasma Clad Ti5Si3reinforced wear resistant intermetallic Composite coatings at room temperature in the condition of dry sliding wear has excellent wear resistance performance and low friction coefficient.The weightlessness of wear is very low,and which increases very slowly with the load increases.