| 摘要 |
1,132,348. Welding by pressure; brazing. SYVANIA ELECTRIC PRODUCTS Inc. 10 Dec., 1965 [11 Dec., 1964], No. 52588/65. Heading B3R. [Also in Division H1] In bonding a refractory metal member to a second metal member a coating of iron is attached to the refractory metal member, the coating is engaged with the second metal member and heat and pressure are applied to the assembly to melt the iron and cause the interdiffusion of the iron into the members with the formation of a diffusion bond. The metal core 19 of a directly heated emissive material carrying filament of an electron discharge device is fixed to the connector 27 affixed to a conductor sealed into the envelope of the device. The core is of refractory metal e.g. tungsten, molybdenum, columbium, platinum, ruthenium or alloys thereof and the connector is e.g. of nickel, steel or alloys thereof and the bonding metal in the form of a sheath 29 on the core is of iron. In an example the end of the tungsten core is dip coated in a slurry containing carbonyl iron, pentacetate and a volatile organic binder, fired in a reducing atmosphere to volatilize the binder and sinter the iron particles and with the iron coating in contact with the nickel plated steel connector current and pressure are applied by a pair of resistance welding electrodes to melt the iron which diffuses into the tungsten and the nickel plated steel connector. In a modification the molybdenum cross member of a "strap frame" electron discharge device electrode is dip coated with the above mentioned slurry, fired to volatilize the binder and sinter the particles, placed in contact with molybdenum side members and heat and pressure applied to the members to cause the iron to melt and diffuse into the members. |
