A mass of diamond crystals in contact with a mass of eutectiferous silicon-rich alloy and a silicon carbide ceramic substrate are disposed in a container and placed within a pressure transmitting powder medium. Pressure is applied to the powder medium resulting in substantially isostatic pressure being applied to the container and its contents sufficient to dimensionally stabilize the container and its contents. The resulting shaped substantially isostatic system of powder-enveloped container is hot-pressed whereby fluid eutectiferous silicon-rich alloy is produced and infiltrated through the interstices between the diamond crystals and contacts the contacting face of the silicon carbide substrate sufficiently producing, upon cooling, an adherently bonded integral composite.