Abstract: A process for preparing a ceramic substrate for metallization wherein a surface of the ceramic substrate is contacted with a composition containing one or more alkali metal compounds, preferably in the form of solid pellets. The pellets are melted on the ceramic surface. As the pellets melt, advancing waves of the molten composition spread across and wet the ceramic surface. The molten alkali metal composition is kept in contact with the ceramic surface for a time period sufficient to etch the surface and thus prepare it for adherent deposition of metal. The moving waves of melting composition supply fresh alkali metal compounds at the ceramic surface. After adhesion promotion, the ceramic surface is treated with compounds that promote adsorption of catalyst for metal deposition before being plated with metal. Uniform surface coverage with catalyst and metal and an improved adherent bond of metal to the ceramic surface are obtained.

Abstract: A process for avoiding blister formation between a metal layer which is electrolessly deposited on a surface of a ceramic substrate and the substrate. The substrate is adhesion promoted with an alkali metal composition containing between 0.35 and 0.9 mole fraction alkali metal compound, and water in an amount which is sufficient to lower the melting temperature of the composition to between 145.degree. and 240.degree. C. and adhesion promote the ceramic surface with the molten composition in a time period between 1 and 200 minutes. Thereafter, the adhesion promoted ceramic surface may be activated to render it receptive to electroless metal deposition. The treated ceramic surface is coated free of blisters using an electroless metal deposition bath with an adherent, metal layer having a thickness greater than 5 micrometers.

Abstract: A process for preparing a ceramic substrate for metallization wherein a surface of the ceramic substrate is contacted with an admixture comprised of an inert solid material and a composition containing one or more alkali metal compounds. The admixture and the substrate are heated at least to a temperature at which the alkali metal composition becomes molten. The molten alkali metal composition is kept in contact with the ceramic surface for a time period sufficient to etch the surface and thus prepare it for adherent deposition of metal. The presence of the inert solid material in the admixture prevents coalescence of the alkali metal composition on the ceramic surface. Uniform surface coverage with catalyst and metal and an adherent bond of metal to the ceramic surface are ensured by treatment with the admixture. Furthermore, an article comprised of metal directly and adherently bonded onto a ceramic substrate is provided.

Abstract: An article comprised of metal directly and adherently bonded onto a ceramic substrate, and a process for producing same, wherein the ceramic is adhesion promoted with molten inorganic compound, treated with compounds that promote adsorption of catalyst for metal deposition, and plated with metal. Uniform surface coverage with catalyst and metal is ensured by the treatment with the adsorption promoters.