Hydrogen-reduction behavior and microstructural characteristics of WO3-CuO powder mixtures with various milling time

Microstructure and hydrogen reduction behavior of WO3-CuO with different milling time are discussed in terms of characteristic of hygrometry curve and W particle size of reduced W-Cu composite powders. With increased milling time, the peak temperatures for the reduction of CuO and WO3 in hygrometry curve are shifted to low temperatures and the peaks, are changed to sharp shape. Microstructural analysis revealed that the hydrogen-reduced powder with milling time of 20 h showed smaller particle size than that of 1 h. The change of reduction behavior and particle size is discussed based on the refinement of oxide powders and resultant increased surface area as well as reduction process of WO2 by CVT. (C) 2003 Elsevier Science B.V. All rights reserved.