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以偏钨酸铵和硝酸铜为原料,柠檬酸为络合剂的溶胶-凝胶法制备WCu复合粉体。利用XRD和TEM对还原前后粉末的物相组成﹑形貌﹑粒度进行分析。TEM显示还原后WCu粉末粒度在100nm左右,Cu相均匀包覆在W颗粒表面。对氧化物粉体的还原性能和机理进行了系统的分析。程序升温还原(TPR)确定了氧化物粉体最佳的两步还原温度分别为500和700℃。红外光谱(FT-IR)分析表明,铜通过氧与钨键合,削弱W-O-W键,使得钨铜复合氧化物还原性增强。
WCu composite powders were prepared by sol-gel method using ammonium metatungstate and copper nitrate as raw materials and citric acid as complexing agent. The phase composition, morphology and particle size of the powders before and after reduction were analyzed by XRD and TEM. TEM shows that the particle size of WCu powder is about 100nm after reduction, and the Cu phase is evenly coated on the surface of W particle. The reduction performance and mechanism of oxide powders were systematically analyzed. Temperature programmed reduction (TPR) confirmed that the best two-step reduction temperature of oxide powders was 500 and 700 ℃, respectively. Infrared spectroscopy (FT-IR) analysis showed that copper weakens the W-O-W bond through the bonding of oxygen and tungsten, which makes the reduction of tungsten-copper composite oxide stronger.