溶胶凝胶法制备超细W-Ag复合粉末

Preparation of ultrafine W-Ag composite powders by sol-gel method

采用溶胶-凝胶法制备了W-Ag复合氧化物粉末,再经过氢还原获得超细W-20%Ag（质量分数）复合粉末。采用热重分析（TG）、X射线衍射仪（XRD）和扫描电镜（SEM）对干凝胶的分解过程,还原前后粉末的物相组成、粒度和形貌进行分析。结果表明：干凝胶在煅烧和还原过程发生一系列的分解和化合反应,随着温度的升高,粉末的相组成、颗粒尺寸和形貌发生明显变化;SEM结果分析表明,还原后W-Ag复合粉末呈球形或近球形,颗粒直径在200~400 nm。

W-20%Ag（mass percent） composite powders were prepared by sol-gel method with AgNO_3 and（NH_4）_6H_2W_（12）O_（40） ？ 5H_2O as raw materials and citric acid as a chelating reagent.The decomposition process of dry gel was checked by means of thermogravimetric analysis.The phase composition,particle size and morphology of the powders were studied by XRD and SEM.The results show that precursor powders undertake a series of decomposing and compound reactions during calcination and reduction.With the increasing of temperature,the phase composition,particle morphology,as well as particle size of the powder change apparently.The granularity of the W-20%Ag（mass percent） composite powders is about 200-400 nm.