(1. 湖南科技大學(xué) 高溫耐磨材料及制備技術(shù)湖南省國防科技重點(diǎn)實(shí)驗(yàn)室，湘潭 411201；
2. 湖南科技大學(xué) 機(jī)電工程學(xué)院，湘潭 411201;
3. 鹽城工學(xué)院 江蘇省新型環(huán)保重點(diǎn)實(shí)驗(yàn)室，鹽城 224051)
摘 要: 以MoSi2、Mo和Al粉末為原料，采用真空熱壓燒結(jié)制備不同Al含量的Mo(Si1-x,Alx)2材料，考察Al含量對(duì)MoSi2材料微觀結(jié)構(gòu)和高溫氧化行為的影響。結(jié)果表明，當(dāng)x=0和0.05時(shí)，Mo(Si1-x,Alx)2材料主要由呈C11b結(jié)構(gòu)的MoSi2組成；當(dāng)x=0.1時(shí)，該材料主要由呈C40結(jié)構(gòu)的Mo(Si0.9,Al0.1)2和MoSi2組成；當(dāng)x=0.2~0.4時(shí)，該材料由呈C40結(jié)構(gòu)的Mo(Si1-x,Alx)2相組成。隨著Al含量的增加，Mo(Si,Al)2晶格膨脹增大。1200 ℃氧化時(shí)，不同Al含量Mo(Si1-x,Alx)2材料的氧化動(dòng)力學(xué)均呈拋物線規(guī)律；Mo(Si,Al)2中Al含量越高，氧化增量越大，抗氧化能力越低。當(dāng)x=0和0.05時(shí)，材料表面氧化生成了連續(xù)致密的SiO2氧化膜；當(dāng)x=0.1時(shí)，氧化層由SiO2？Al2O3混合氧化膜組成；當(dāng)x=0.2~0.4時(shí)，材料表面氧化生成連續(xù)的Al2O3氧化膜。由于Si和Al的擴(kuò)散，氧化膜與Mo(Si1-x,Alx)2界面處形成了Mo5(Si,Al)3過渡區(qū)。
關(guān)鍵字: MoSi2；Al合金化；氧化膜；氧化行為
（1. Hunan Provincial Key Defense Laboratory of High Temperature Wear-resisting Materials and Preparation Technology, Hunan University of Science and Technology, Xiangtan 411201, China;
2. College of Mechanic and Electrical Engineering, Hunan University of Science and Technology,
Xiangtan 411201, China;
3. Key Laboratory for Advanced Technology in Environmental Protection of Jiangsu Province,
Yancheng Institute of Technology, Yancheng 224051, China）
Abstract:Mo(Si1-x,Alx)2 material was fabricated by hot press sintering using MoSi2, Mo and Al powders as raw materials. The effects of alloying element Al on the microstructure and high temperature oxidation behaviors of MoSi2 were investigated. The results show that the Mo(Si1-x,Alx)2 material mainly contains MoSi2 with C11b tetragonal structure at x of 0 and 0.05. At x of 0.1, the mixture phases of hexagonal C40 Mo(Si,Al)2 and MoSi2 are detected. Only hexagonal C40 Mo(Si,Al)2 phase is found when the Al content x changes from 0.2 to 0.4. The lattice of each structure generally expands with increasing the substitution ratio of Al. The oxidation kinetics of all materials at 1200 ℃ follows a parabolic rate law. The higher the Al content in Mo(Si,Al)2 is, the more the mass gain of Mo(Si,Al)2 is, and the lower the oxidation resistance is. A dense and continuous SiO2 scale forms on the surface of both MoSi2 and Mo(Si0.95,Al0.05)2. The oxide scale comprises of SiO2 and Al2O3 in Mo(Si0.9,Al0.1)2 material, and the Al2O3 oxide scale forms on the surface of Mo(Si0.8,Al0.2)2, Mo(Si0.7,Al0.3)2 and Mo(Si0.6,Al0.4)2 materials. The Mo5(Si,Al)3 transition layer is found between the boundary of oxide scale and the Mo(Si,Al)2 substrate because of the diffusion of Si and Al elements.
Key words: MoSi2; Al alloying; oxide scale; oxidation behavior
