Bulk and grain boundary diffusion of C in tungsten hemicarbide

Dense tungsten hemicarbide specimens were used to study the bulk and grain boundary diffusion of ¹⁴C into W₂C at temperatures of 1200 to 2000°C. The bulk diffusion coefficient is given by:

$\text{D}{}_{\mathrm{v}}\text{=18.3}\text{exp}\text{?}\text{91,500}\text{RT}\text{cm}{}^2\text{s}{}^{\mathrm{?1}}$

The grain boundary diffusion coefficient is represented by the expression:

$\text{P}{}_{\mathrm{GB}}\text{=1.8 10}{}^{\mathrm{?4}}\text{exp}\text{?}\text{68,880}\text{RT}\text{cm}{}^2\text{s}{}^{\mathrm{?1}}$

A comparison is give with preceding results on other carbides.