激光熔覆Ti-Al-N复合涂层高温氧化及摩擦磨损性能

High-temperature oxidation and wear properties of laser cladded Ti−Al−N composite coatings

采用激光熔覆于TC4合金表面原位合成Ti-Al-N复合涂层,对比研究复合涂层及TC4基体的高温氧化行为及宽温域下的摩擦磨损性能。结果表明:复合涂层在800℃以下生成以TiO_(2)为主的多层膜,在900和1000℃下涂层氧化产物为TiO_(2)和Al_(2)O_(3)的混合氧化层,涂层表现出较好的抗高温氧化性能;由于氧化膜增厚及涂层中分布的Ti_2AlN自润滑相的作用,800℃时涂层摩擦因数降至0.2091,磨损率降至0.025×10^(-4)mm^3·N^(-1)·m^(-1)是TC4钛合金基体的1.43%。复合涂层在测试温度区间以磨粒磨损为主,高温条件下氧化物具有明显的润滑作用。

Ti−Al−N composite coatings were in-situ synthesized on TC4 surfaces by laser cladding.The oxidation behaviors and wear properties of the as-obtained composite coatings and TC4 matrix were studied at various temperatures.The results showed the formation of a TiO_(2)-dominated multilayer film on the composite coating surface at temperatures below 800℃.The oxidation product of the coating contained a mixed oxide layer of TiO_(2) and Al_(2)O_(3) at 900 and 1000℃.The coatings exhibited good oxidation resistance at high temperatures.The thickening of the oxide film and distribution of the self-lubricating phase Ti2AlN in the coating decreased the friction coefficient to 0.2091.Also,the wear rate diminished to 0.025×10^(-4)mm^3·N^(-1)·m^(-1)at 800℃,which is 1.43%that of the TC4 substrate.In the tested temperature range,the composite coatings showed mainly abrasive wear behavior,while an obvious lubrication effect was observed for oxide at high temperatures.