Abstract
The X-ray line broadening of tungsten powder has been studied in relation to its oxidation rate. When β cos θ is plotted against sin θ, β being the line breadth at half maximum at the Bragg angle θ, a zig-zag line is obtained which is inclined to the sin θ axis on an average. The results show that the oxidation rate is closely related to the averge inclination of the zig-zag line and the level height of β cos θ corresponding to (200), measured from tht corresponding to (110). A change of such a relative level height and of the inclination by heating or compressing the powder is accompanied by a decrease or increase of the oxidation rate. The shape of the zig-zag line and oxidation rate of tungsten powder are independent of the particle size and the quantity that has been dissolved. This indicates that the crystal structure is homogeneous throughout the entire part of any particle. It is believed that the phenomenon of such line broadening is dependent on the crystallite size, lattice distortion and irregularities which greatly affect the chemical reactivity.
