环境障涂层用Yb2Si2O7粉体的溶胶凝胶法制备及表征

摘要

Yb2Si2 O7 powders were synthesized by a sol-gel method using ytterbium nitrate and tetraethyl orthosilicate as starting materials.The effects of ethanol concentration on the sol-gel process and the final particle size were studied.The phase evolutions,thermal history of the gel were investigated using X-ray diffraction,TG-DTA and Raman spectra.The results indicated that higher content of alcohol solvent in the sol conduced to smaller and uniform particle size,but the sol-gel time was prolonged.Yb(NO3)3and C2H5OH molar ratio is 1∶ 10,after calcining the gel at 1200℃ for 2h,Yb2Si2 O7 powders were obtained,and the average particle size was 130nm ～ 140nm,and are suitable for environmental barrier coating for SiC ceramic matrix composites.%以Vb(NO3)3·5H2O和TEOS为初始原料采用溶胶凝胶工艺制备Yb2Si2O7粉体,研究了乙醇的含量对溶胶凝胶过程和粉体粒径形貌的影响,并通过X射线衍射分析、热重差热分析及拉曼光谱分析对凝胶的相转变和热历程进行分析.研究表明,乙醇含量增加,粉体粒径减小,粒度均匀,溶胶凝胶时间延长;Yb(NO3)3与C2H5OH的摩尔比为1∶10,制备的凝胶经过1200℃煅烧2h后得到单相的β-Yb2Si2O7粉体,粉体粒径大小为130nm ～140nm,粉体可作为环境障涂层材料应用于碳化硅陶瓷基复合材料的腐蚀防护.