Bonded solderable silver article, composition, and method of bonding silver to a ceramic substrate

摘要

A composition for a solderable silver article of manufacture as well as a method of bonding silver to a ceramic substrate which includes a total composition of silver, cadmium oxide, copper oxide, rhuthenium oxide and palladium. An initial mixture of between 1.0 - 6.0% by weight of the total composition of cadmium oxide and copper oxide is provided in a pre-determined weight ratios. The initial mixture is blended with between 1.0 - 8.0% of palladium powder and about 0.2 - 3.0% of rhuthenium oxide to form an intermediate mixture. Silver powder is then added to the intermediate mixture to form a total composition mixture. The total composition mixture is blended in an organic binder and applied to a ceramic substrate to form a pre-determined coating layer thickness. The coated ceramic article is introduced into an oven having an oxidizing atmosphere which is maintained within a temperature range of 900 DEG C to 950 DEG C. Copper oxide crystals impregnate the ceramic substrate and form a high strength bond between the silver layer and the ceramic substrate. The palladium in a combination with the rhuthenium oxide slows down scavenging of the silver when the coated ceramic substrate is soldered. The addition of the rhuthenium oxide has been found to allow a lower percentage of palladium to be added to the total composition than that which has been previously used while maintaining high solderability of the silver layer.