Abstract: An improved process for metallizing a ceramic substrate for the purpose of producing a metal layer having uniformly good adhesion as measured by peel strength. The improvement is a pretreatment process in which the firing skin, i.e., the glass-like surface of the ceramic substrate is removed and the exposed surface of the ceramic substrate is positively roughened. The pretreatment includes a chemical etching step during which the ceramic substrate contacts a melt bath containing molten alkali hydroxide and an additive, which additive preferably is water. From 0.01 to 80 weight %, preferably from 1 to 5 weight %, of water is included in the melt bath. Rather than reducing the etching rate because of dilution, the rate increased unexpectedly. Moreover, the metallization resulted in a metal layer having very good adhesion, which adhesion can be further improved by chemically etching the ceramic substrate under a protective gas atmosphere, preferably a wet protective gas atmosphere.

Abstract: A process for etching at least a portion of a surface of a ceramic substrate preparatory to metal-plating thereof, the process including, applying to the surface of the ceramic substrate a substantially uniform coating of a chemical precursor of an alkaline etching substance; and treating the chemical precursor to chemically transform it into the alkaline etching substance and etch the surface. Preferably the at least one chemical precursor is an organic alkali compound or an organic alkaline earth compound.

Abstract: Process for chemically metallizing an inorganic substrate, which is a poor conductor of electricity, e.g. a ceramic material or glass. The surface of the substrate is chemically activated so that chemical bonds are more readily formed with a subsequently applied, inorganic adhesion promoter. The adhesion promoter in turn facilitates chemical bonding with a subseqently applied metal layer, e.g. a copper layer, which is applied by a wet chemical method. The activation step and the step of applying an adhesion promoter, in combination with at least one thermal treatment, results in an adhesive strength between the metal layer and the substrate surface which equals or exceeds the adhesion strength of the surface of the substrate material.

Abstract: The present invention relates to a process for wet metal-plating of ceramic substrates. More particularly this invention relates to the wet chemical copper plating of Al.sub.2 O.sub.3 ceramics. It is essentially composed of a combined chemical pretreatment of the ceramic surface for chemical metallization without external electric current in such a manner that within only a single pretreatment step the substrate surface is chemically activated and is simultaneously covered with an adhesion promoter, and/or a sensitizer and/or an activator (catalyst).

Abstract: An apparatus for treating ceramic objects in alkali hydroxide melts for the purpose of cleaning and roughening them for a subsequent metallization. The apparatus permits various types of ceramics to be subjected to an etching treatment which can be predetermined and is easily reproducible with respect to the treatment temperature and time and the constant composition of the alkali hydroxide melt.