Abstract: A process for preparing an insulated metallized substrate, wherein a specified metallized substrate is heated from ambient temperature to a peak temperature of at least about 800 degrees centigrade while contacting the substrate with an inert atmosphere containing less than 10 parts per million of oxygen, maintained at such peak temperature for a specified period of time while being contacted with said inert gas, and thereafter heated at a peak temperature of at least about 800 degrees centigrade while being contacted with a gas containing at least 100 parts per million of oxygen.

Abstract: A metallized ceramic substrate having an enhanced bond strength between the ceramic substrate and a conductive metal layer bonded thereto is disclosed. The metallized ceramic substrate includes a heterogeneous juncture band between a ceramic workpiece and a layer of electrically conductive material. A process for making the metallized ceramic substrate is also disclosed. The process includes an acid etchant step that increases the actual surface area of the treated surface of the ceramic workpiece without undermining the integrity of the ceramic surface while at the same time selectively attacking vitreous binder phase present between substrate grains and creating even deeper penetration at the relatively higher energy triple point junctures. In this manner, metal anchor sites that enhance adhesion are provided. During subsequent high temperature firing these anchors hold the resulting composite together as a chemical bond is formed in addition to a mechanical bond or interlock.