Abstract: A housing for a microwave circuit is formed from a base made of metal matrix composite material and walls made of sheet metal. The base and the walls are joined together by diffusion soldering. Some holes to receive feedthroughs are formed at the junction of the base and a wall.

Abstract: A method of joining components by soldering comprising forming discrete layers of silver (13, 17) and another metal (19), e.g. a tin or indium based material, the two layers having volumes in a ratio different from that in the eutectic alloy formed by silver and that metal, and raising the temperature of the layers above the melting point of the eutectic alloy for a period sufficient to cause initially formation of the eutectic alloy and then, by reaction between the eutectic alloy and one or other of silver and the other metal, formation of a material having a melting point higher than the eutectic alloy melting point. The method allows soldering, e.g. of a silicon wafer (1) to a header (3), at a relatively low temperature below that which the joint will withstand after formation.

Abstract: A method of making material in the form of a fine wire or thin strip or sheet suitable for use as electrical conductors comprises: forming an ingot substantially consisting of an alloy of gold and one or more of the metals titanium, lutetium, zirconium, scandium and hafnium, the amount of the or each of said one or more of the metals in the alloy lying in the range from substantially 0.1 at % to an upper limit comprising the atomic percentage of that metal corresponding to the maximum solubility of that metal in the alloy; solution heat treating the ingot and then quenching the ingot from the solution heat treatment temperature; mechanically working the ingot to have a maximum dimension in at least one direction of not greater than 250 .mu.m; and heat treating the resulting material at a temperature below its solvus temperature from an ambient atmosphere containing oxygen and/or nitrogen in the ambient atmosphere.

Abstract: A method of brazing a silicon component to a molybdenum and/or tungsten component wherein prior to brazing the surface of the molybdenum and/or tungsten component is first provided with a thin gold coating and then a coating of palladium, platinum or rhodium. This allows satisfactory brazing to be effected using conventional aluminum-based brazes at temperatures below 650.degree. C.