Preparation of WCu Composite Powders by Sol-Gel Method and Their Reduction Behavior

Abstract:

WCu composite powders were prepared by the sol-gel method with Cu(NO3)2·3H2O and (NH4)6H2W12O40·5H2O as raw materials and citric acid as chelating reagent. The composition, morphology and particle size of the powders were studied by XRD and TEM. TEM observation results show that the particle size of WCu powders is about 100 nm after reduction and the W grains were covered homogeneously by Cu on the surface. The reduction behavior and mechanism of the oxide powders were analyzed systematically. Temperature programmed reduction (TPR) result indicates that the appropriate two-step reduction temperatures are 500 and 700 oC. The FT-IR analyses reveal that the bond of W-O-W is weakened due to the bond of Cu-O-W, leading to the increase of the reduction properties of the WCu composite oxide powders.