Abstract: A new PCD/PCBN tool and method for making the same involve the use of an intermediate layer of polycrystalline material between a substrate and an outer working layer. The intermediate layer is formulated to limit or prevent the amount of cobalt or other binders which may infiltrate the outer working layer and accelerate deterioration under high throughput conditions. In accordance with one aspect of the invention, the substrate is corrugate or rounded projections to both reduce stress and to decrease infiltration of cobalt through the polycrystalline structures. In accordance with another aspect of the invention, the bonding medium and/or binder agents in the intermediate layer may be selected to decrease mobility of cobalt and the like.