Abstract: A polycrystalline cubic boron nitride (PcBN) is fabricated using a process of overlaying layers of cubic boron nitride (cBN) powder, where the layers have cBN mixed with various concentrations of a ceramic. The process of fabricating the PcBN includes depositing, in a refractory capsule, a carbide, a cubic boron nitride (cBN), and a mixture of cBN and a ceramic, then applying a high pressure and high temperature (HPHT) to the content of the refractory capsule. During the depositing step of the process, the concentration of cBN in the mixture of the cBN and ceramic is lower than the concentration of cBN that is in the layer below it. Upon applying HPHT, the carbide first diffuses across the cBN layer, and then diffuses across the layer with the mixture of the cBN and ceramic. After HPHT ends and the content of the refractory capsule cools, the process yields a PcBN having layers with various concentrations of cBN, and at least one cBN layer with a ceramic material.