A WC—Co material or polycrystalline diamond-Co material that has a gradient in the grain size of the particles. Specifically, the material may have a top layer that has coarse grains that is designed to dissipate the heat caused by friction (and thus prevent thermal cracking). The material will then have a bulk substrate that is made up of finer grains and provide adequate hardness for the material. The top layer is positioned on top of the bulk substrate.