纯钛表面多步合成Ti-Al梯度抗氧化涂层

摘要:

以TA2工业纯钛为基体材料,通过微弧氧化技术及磁控溅射技术在TA2基体表面分别制备了氧化钛薄膜和金属铝涂层,从而形成Ti/TiO2/Al结构试样,然后进行500℃×4 h的真空扩散热处理,研究了TA2纯钛基体表面Ti、Al元素梯度过渡的复合抗氧化涂层的形成机制,以及涂层在700℃下的循环氧化性能。结果表明,Ti/TiO2/Al试样中的金属Al涂层在500℃的真空热处理过程中,不仅能够扩散至Ti基体内形成Ti-Al系列金属间化合物,而且能与TiO2中间层发生化学反应形成TiAl3+Ti Al+Al2O3复合涂层。TA2纯钛基体表面形成Ti-Al梯度抗氧化涂层后,在700℃大气环境中循环氧化50次后的氧化增重仅为无涂层试样的1/10。

Abstract:

A composite coating including top-layer( Al) and interlayer( TiO2) was coated on TA2 through magnetron sputtering and micro-arc oxidation,respectively. The formation mechanism of the composite anti-oxidation coating with excessive gradient of Ti and Al on substrate was explored by vacuum-diffusional annealing at 500 ℃ for 4 h. In addition,the cyclic oxidation resistance of the coating was studied through cyclic oxidation heat treatment in atmospheric environment at 700 ℃. The results show that the Al element in the Ti/TiO2/Al sample can not only diffuse into the Ti substrate to form Ti-Al intermetallic compounds,but also react with the TiO_2 intermediate layer to form the( TiAl3+TiAl + Al2O3) composite coating during vacuum heat treatment at 500 ℃. Furthermore,the oxidation resistance of Ti samples with the coating is about 10 times higher than that of bare Ti in 50 cycle test at 700 ℃.