Abstract: A method is disclosed for restoring weathered plastic surfaces and for enhancing the resistance of the treated surface to sunlight. The surface of a plastic article being treated is first cleaned with a suitable cleaning agent and the surface is polished with a mild abrasive to remove major imperfections in the surface. Following cleaning and polishing, a first layer of an uncured adhesive material is applied over the surface. The adhesive material is selected from those compositions that are ultraviolet curable. An outer coat of a curable adhesive is applied over the uncured to form a semi-permanent outer surface on the article. The article then can be exposed to sunlight and other effects of weathering and over a period of time the underyling ultraviolet curable coating is gradually cured by exposure to sunlight so that the composite coating on the surface of the article becomes even tougher and better cured the more the article is exposed to sunlight.

Abstract: Dense metal vias in pure alumina substrates are derived from a metallization composition having 80-97% refractory metal, 2-15% alumina, 0.05-5% sintering aid, and 0-5% bonding additive; it has been found that for alumina contents greater than about 12%, a bonding additive is not required. The same compositions, absent the sintering aid, can be used to form bimetallic vias; these vias include a porous metal network where the pores are infiltrated with another metal, for example, porous tungsten infiltrated with copper.

Abstract: Bonding additives for refractory metallization compositions allow for circuit traces having good resistivities and adhesion values in excess of 6 kpsi, generally between about 10 and 20 kpsi. The inks are provided in formulations devoid of a glass component, and are suitable for co-sintering circuit traces and vias with 96% alumina substrates, and especially for 99% alumina substrates. Suitable bonding additives are the oxides of molybdenum, tungsten, niobium, manganese, yttrium, and titanium, or mixtures of such oxides.

Abstract: Dense vias may be made with a metallizing composition containing tungsten, alumina, and either nickel or palladium. Further, an infiltration process ensures that vias in ceramic substrates are heremetic. Infiltrating materials, including metals and alloys, are applied to co-fired substrates and the composite is fired. The process may be repeated if necessary. Alternatively, the via holes may be bore-coated prior to infiltrating.

Abstract: A tungsten paste suitable for co-sintering with 98+% alumina substrate can be produced by adding selected compositions of glass to the paste. Circuit packages produced in accordance with the present invention exhibit superior thermal conductivity, low shrinkage variability, and smoother and more homogeneous surface finish. A preferred embodiment of the invention utilizes a substrate comprising narrow size range alumina powder, thus yielding lower sintering temperature and further improvements in shrinkage variability and surface finish.