Synthesis and characteristics of W-Ni-Fe nano-composite powders prepared by mechanical alloying

The mixture of 90W-7Ni-3Fe (mass fraction, %) powders was milled in a planetary ball mill. Its structure changed during milling, the surface characteristics and thermal stability of the milled powders were studied with x-ray diffraction (XRD), Brunaure-Emmett-Teller (BET) nitrogen adsorption technique and differential thermal analysis (DTA). The results show that high-energy ball milling leads to the formation of composite powders with amorphous binder phase and supersaturated W(Ni,Fe) nano-crystalline grains in which great lattice distortion exists. The crystallization temperature of the amorphous binder phase during heating decreases with milling time. The specific surface area and the pore size of the powder mixtures decreases with milling time due to agglomeration and welding between particles.