气体成分对Al_2O_3-TiO_2涂层结构和硬度的影响

Effect of gas composition on structure and hardness of Al_2O_3-TiO_2 coat

为了研究低功率等离子喷涂中工作气体成分对涂层结构和硬度的影响规律,在试验中我们分别使用了氩 氢和氩 氮等离子炬,在输入相同功率(5kW)的条件下,改变混合气体中氢气与氮气的百分含量,来喷涂Al2O3 TiO2涂层.结果表明,用氩 氮等离子炬喷涂的涂层比较粗糙,相图中层间距较大,气孔较多;而用氩 氢等离子炬喷涂的涂层则比较均匀,层间距比较小,气孔也比较少,涂层比较致密,其硬度明显高于氩 氮等离子炬喷涂的涂层,Hv可以达到1243kg·mm-2.

To study the law of effect of working gas on coat structure and hardness in low power plasma spraying, argon-hydrogen plasma torch and argon-nitrogen plasma torch respectively in the experiment are used. Under the circumstance of the same power input (5 kW), Al_2O_3-TiO_2 coat was sprayed changing the percent of hydrogen or nitrogen in compound gases. The results indicate that the coat sprayed with argon-nitrogen plasma torch was rough, and its distance between commutator segments was bigger and porosity was higher, while that sprayed with argon-hydrogen plasma torch, was uniform and had smaller distance between commutator segments and lower porosity, and was dense. The hardness of the latter coat that could reach Hv 1 243 kg·mm^(-2), was much higher than that of the former one.