In a protective gas atmosphere, at least one metal of high vapor pressure (diffusion metal) is admitted as an alloying component through diffusion into the impregnating metal of lower melting point such as silver or copper contained in the pores of the frame metal, such as tungsten, rhenium or molybdenum. The diffusion temperature is chosen so that the impregnating metal exists in the liquid phase at least after the diffusion of the diffusion metals. The diffusion takes place, preferably, at 20 to 240.degree.C above the melting temperature of the impregnating metal or the alloy formed between the impregnating metal and the diffusion metal. As the diffusion metal is used at least one of the metals bismuth, cadmium, gallium, indium, lead, tin and tellurium.
A vacuum interrupter of improved large current interrupting capability and dielectric strength has a pair of separable electrodes (5,6) a vacuum envelope (4) electrically insulating and enclosing the pair therewithin, a contact-making portion (14) of material of 20 to 60% IACS electrical conductivity being a part of one electrode (6) of the pair, a magnetically arc-rotating portion (13) of material of 2 to 30% IACS electrical conductivity secured to the contact-making portion (14) so as to be apart from the other electrode (5) when the electrodes (5,6) are in engagement, and means, which include a plurality of slots extending radially and circumferentially of the magnetically arc-rotating portion (13) and being apart from each other, for magnetically rotating the arc established between the electrodes (5,6) on an arcing surface of the electrode (6).
A vacuum interrupter of more improved large current interrupting capability and dielectric strength is disclosed. The interrupter has a pair of separable contact-electrodes (13, 24), a vacuum envelope (4) generally electrically insulating and enclosing the pair therewithin, a contact-making portion (19) of 20 to 60% IACS electrical conductivity being a part of one contact-electrode (13) of the pair and being into and out of engagement with the other contact-electrode (24) of the pair, an arc-diffusing portion (20) of 2 to 30% IACS electrical conductivity being the other part of the one contact-electrode (13) and being electrically and mechanically connected to the contact-making portion (19) so as to be spaced from the other contact-electrode (24) when the contact-electrodes (13, 24) are into engagement, and means (14, 15) for applying an axial magnetic field in parallel to an arc established between the contact-electrodes (13, 24) when separated.
Contact materials of a vacuum interrupter and producing process therefor are disclosed. The contact materials provide a contact which is much high in relatively large current and small lagging and leading current interrupting capabilities and dielectric strength while a little in an anti-welding capability down. The contact materials are composed of between 20 and 70 weight % copper, between 5 and 70 weight % molybdenum and between 5 and 70 weight % chromium. The contact material is produced by diffusion bonding a mixture of molybdenum powder and chromium powder into a porous matrix and infiltrating the matrix with copper. Alternatively, the contact materials may be produced by sintering a mixture of three metal powders.
