Mo-Si-Al系金属化合物的制备及其高温抗氧化性能

Preparation and high temperature oxidation resistant properties of Mo-Si-Al intermetallic compounds

Mo-Si系金属化合物因具有良好的高温抗氧化性而备受瞩目,但是其在高温环境下缺乏抗蠕变性能,在500℃左右就会发生加速氧化现象,使其应用受到限制。本研究利用熔射涂层法,将Al-Si混合物熔覆于基体金属Mo表面,并置于700~1 100℃真空状态下进行扩散反应,成功地在金属Mo表面制备出Mo(Si,Al)2金属间化合物层。将表层进行了Mo(Si,Al)2涂层的样品在大气中1 200℃进行10 h高温氧化试验,Mo(Si,Al)2涂层表现出良好的高温抗氧化性。另外,由于空气中氧元素与化合物层中Al、Si元素反应后形成Al2O3、Si O2,造成化合物层表面Al元素含量降低,而出现了Mo5Si3、Mo Si2化合物层。

The Mo-Si based intermetallic compounds have attracted much attention for their good oxidation resistance at high temperatures. However,they show low creep resistance in the high temperature environment,and the accelerated oxidation will occur at about 500 oC,which limits their application. In this study,the AlSi mixture was covered on the surface of metal Mo by the coating method and then the diffusion reactions were carried out at high temperatures from 700 to 1 100 oC in vacuum. A Mo（Si,Al）_2 compound layer on Mo surface was successfully prepared. The high temperature oxidations for samples with Mo（Si,Al）_2 layers were tested at 1 200 oC in air for 10 hours. The Mo（Si,Al）_2 layer showed excellent oxidation resistance. In addition,Mo_5Si_3 and MoSi_2 compounds were observed. The reason is that Al and Si elements are oxidized by oxygen element in air,resulting in the decrease of Al content on the surface layer.