Abstract: The invention relates to a process for producing a material based on silver-carbon, that involves the steps of: (i) providing a suspension of carbon particles; and (ii) supplying a solution of a silver compound and of a reducing agent, such that a silver-containing precipitate is deposited onto the carbon particles, where the carbon particles have a mean diameter of 200 nm or greater. The invention further relates to a material obtainable by this process and to the use of the material in circuit breakers for low-voltage power engineering.

Abstract: The present invention relates to a method for manufacture of silver-based composite powders for electrical contact materials. The invention relates also to electrical contact materials made from such composite powders. The process comprises a high energy dispersing process of wet silver oxide (Ag2O) with additional second oxide components in aqueous suspension. The high energy dispersing process can be conducted by high shear mixing or by high energy milling. Preferably high speed dispersing units working at rotating speeds in the range of 5,000 to 30,000 rpm or high energy mills such as attritor mills are used. The new process is versatile, economical and offers access to a broad spectrum of contact materials. The silver-based composite powders made according to the new process yield contact materials with a highly dispersed microstructures and superior material characteristics.

Abstract: The invention relates to a process for producing a material based on silver-carbon, comprising the steps of: (i) providing a suspension of carbon particles; and (ii) supplying a solution of a silver compound and of a reducing agent, such that a silver-containing precipitate is deposited onto the carbon particles, where the carbon particles have a mean diameter of 200 nm or greater. The invention further relates to a material obtainable by this process and to the use of the material in circuit breakers for low-voltage power engineering.

Abstract: The present invention relates to a method for manufacture of silver-based composite powders for electrical contact materials. The invention relates also to electrical contact materials made from such composite powders. The process comprises a high energy dispersing process of wet silver oxide (Ag2O) with additional second oxide components in aqueous suspension. The high energy dispersing process can be conducted by high shear mixing or by high energy milling. Preferably high speed dispersing units working at rotating speeds in the range of 5,000 to 30,000 rpm or high energy mills such as attritor mills are used. The new process is versatile, economical and offers access to a broad spectrum of contact materials. The silver-based composite powders made according to the new process yield contact materials with a highly dispersed microstructures and superior material characteristics.

Abstract: A method for producing composite powders based on silver-tin oxide, by chemically reductive precipitation of silver onto particulate tin oxide. A solution of a silver compound and a solution of a reducing agent are simultaneously added in stoichiometrically equivalent amounts, separately and continuously with intensive mixing, to an aqueous suspension of tin oxide. The resulting composite powders have very high homogeneity, and can be processed to make electrical contact materials. The method is particularly suitable for producing composite powders based on silver-tin oxide doped with indium oxide, to be used in the manufacture of electrical contact materials.

Abstract: A method for producing composite powders based on silver-tin oxide, by chemically reductive precipitation of silver onto particulate tin oxide. A solution of a silver compound and a solution of a reducing agent are simultaneously added in stoichiometrically equivalent amounts, separately and continuously with intensive mixing, to an aqueous suspension of tin oxide.

Abstract: Sintered silver-iron material for electrical contacts, with properties comparable with those of silver-nickel materials, is obtained by using iron powder having more than 0.25% carbon by weight and microhardness higher than 200 HV 0.025 and sintering in a hydrogen-free protective gas.

Abstract: Silver-iron materials for electrical switching contacts with properties which come very close to those of silver-nickel materials formed of 0.5 to 4.5% by weight iron and 0.05 to 2% by weight of one or more of the oxides magnesium oxide, calcium oxide, yttrium oxide, lanthanum oxide, titanium oxide, zirconium oxide, hafnium oxide, cerium oxide, niobium oxide, tantalum oxide, chromium oxide, manganese oxide, iron oxide, zinc oxide, aluminum oxide, indium oxide, silicon oxide, and tin oxide, the balance being silver.

Abstract: Silver-iron materials for electrical switching contacts with properties which come very close to those of silver-nickel materials formed of 4.6 to 15% by weight iron and 0.05 to 5% by weight of one or more of the oxides magnesium oxide, calcium oxide, yttrium oxide, lanthanum oxide, cerium oxide, chromium oxide, iron oxide, aluminum oxide, indium oxide, silicon oxide, and tin oxide, the balance being silver.

Abstract: An electrical contact material for switching rated currents between 20 and 100 Ampere having improved operational life made of 3.2 to 19.9 wt-% tin oxide and 0.05 to 0.4 wt-%, in each case, of indium oxide and bismuth oxide, the remainder being silver. In the course of the manufacture of the material by powder metallurgy more than 60 wt-% of the tin oxide should exhibit a particle size of more than 1 .mu.m.

Abstract: Silver-iron materials for electrical switching contacts with properties which come very close to those of silver-nickel materials formed of 0.5 to 20% by weight iron 0.5 to 5% by one or more of the elements rhenium, iridium, and ruthenium, and 0.05 to 2% by weight of one or more of the oxides magnesium oxide, calcium oxide, yttrium oxide, lanthanum oxide, titanium oxide, zirconium oxide, hafnium oxide, cerium oxide, niobium oxide, tantalum oxide, chromium oxide, manganese oxide, iron oxide, zinc oxide, copper oxide, aluminum oxide, indium oxide, silicon oxide, and tin oxide, the balance being silver.

Abstract: Electrical contacts are formed from a silver-iron material which contains 3 to 30% by weight of iron and one or more of the components manganese, copper, zinc, antimony, bismuth oxide, molybdenum oxide, tungsten oxide or chromium nitride in amount totalling 0.05 to 5 weight percent, the balance being silver. These materials are suitable for forming electrical contacts of a wide variety. Tantalum is an optional component which may also be utilized particularly when 0.2 percent to 2 percent zinc is present.

Abstract: There is described an electrical contact piece made of a silver-metal oxide material as contact coating, a carrier made of copper, or iron and an intermediate layer which furnishes a high adhesive strength of the contact coating to the contact carrier even at a high number of switchings. The intermediate layer consist essentially of a silver alloy having 2 to 12 weight % of tin, indium, and/or germanium.

Abstract: There is described a contact material based on silver-tin oxide and additional metal oxide having a high working life, slight welding strength and low switching temperatures. Besides silver and tin oxide it contains 0.05 to 4% of molybdenum oxide and/or germanium oxide.

Abstract: There is described a material for electrical contacts based on silver having 5 to 20 weight % tin oxide and 0.5 to 5 weight % tungsten oxide which has the welding strength reduced further without producing an increased switching temperature. The material contains additionally 0.1 to 5 weight % of bismuth oxide.