Copper Powder (Atomized Metal) - Weight: 1kg - By Inoxia

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To 1,62 kg of copper hydroxide powder was added 4,8 kg of 80-percent aqueous formic acid solution, and this mixture was stirred for one hour. By filtration of the obtained mixture, copper formate tetrahydrate was obtained, which was then dehydrated at 100 ° C in vacuo to obtain anhydrous copper formate. A method as claimed in claim 1 for producing a purified fine copper powder which comprises washing the fine copper powder obtained by the method claimed in claim 1 with water, an organic solvent or a solution of a rust inhibitor for copper in water or in an organic Solvent so as to reduce in said powder at least one impurity element selected from the group consisting of halogens, sulfur, alkali metals and heavy metals. In addition, with the exception of anhydrous copper formate, all copper compounds must be heated in a reducing atmosphere (H 2 gas) to form metallic copper powder, and their reactions in the reducing atmosphere are exothermic, their exothermic amounts of heat at least five times greater than that of anhydrous copper formate are. Highly pure, very fine 325 mesh irregular copper metal powder suitable for a range of applications including resin-casting (cold casting), decorative coatings and powder metallurgy.

Some of the most widely used general purpose high purity copper powders are listed bellow. Specifications are based on a typical analysis. Fine copper powders for use for the above purposes are prepared, for example, by reduction precipitation of a copper compound in the liquid phase, evaporation in a vacuum or in an inert gas, gas phase reduction of a copper salt, and solid phase reduction of an oxide. For low-duty shaft bearings where the static load-carrying capacity is adequate; where lubrication is impossible; and where the only requirement is low cost and avoidance of heating, seizure or squeaking throughout the life of the appliance or machine.As compared with the copper powders obtained by the reduction method and the like, the fine copper powder produced by the method of the present invention is more slowly oxidized in the air. Therefore, even if the fine copper powder according to the present invention is left in the air, no color change caused by oxidation takes place unless the duration of exposure is short. Since the produced fine copper powder contains impurity elements which were originally contained in the anhydrous copper formate powder which was expected to be present, and most of which adhere to the surface of the powder particles, it is preferred that the fine copper powder be mixed with water, an organic solvent or an organic solvent Solution of a rust inhibitor for copper in water or in an organic solvent is washed to reduce the impurity elements, such as halogens, sulfur, alkali metals and heavy metals. By such a washing treatment, for example, 90% or more of the alkali metals and halogens present as impurity elements may be removed, though depending on the amount of these impurity elements.

The sintered yield strength increases from 11 ksi (26 MPa) at 7% aluminum to 40 ksi (276 MPa) at 11% aluminum; heat treatment of the latter alloy increases the yield strength to 60 ksi (414 MPa). Tensile strengths increase uniformly from 32 ksi (221 MPa) for the 7% alloy to 65 ksi (448 MPa) for the heat treated 11% alloy. Elongations of the 5% to 9% alloys are in the 25-35% range; the two phase alloys are considerably less ductile. 4 These properties make the P/M aluminum bronzes suitable for the production of parts where the strength requirements are too high to be met by the tin bronzes. Hirschhorn, Introduction to Powder Metallurgy. New York, American Powder Metallurgy Institute, 1969. For a lot number with a filling-code such as 05427ES-021, enter it as 05427ES (without the filling-code '-021'). In the above process, the starting compounds may remain unreacted depending on the reaction conditions, by-products may be formed in addition to the copper formate, or the copper formate may further react to form other compounds. In this way, the resulting copper formate contains such other compounds. For example, since copper formate is remarkably unstable in aqueous solution, the greater the proportion of water and the higher the temperature, the more the formation of water-insoluble products such as basic copper formates is accelerated due to side reactions or subsequent decomposition reactions. Any unreacted starting compounds, such as copper carbonate, copper hydroxide and copper oxide, and the products of side reactions or decomposition reactions, such as basic copper formates, can be converted by reduction into metallic copper, without any substance included in the copper being supplied. However, since the reduction reaction is accompanied by considerable heat generation and thereby water forms, such copper compounds are not suitable for the thermal solid phase decomposition in the method of the present invention, because the use of such compounds requires calorimetric control and other complicated procedures. Powder metallurgy, the technology of utilizing metal powders, offers the engineer a means conserving materials, reducing machining and securing a uniform product at a reasonable cost. This unique metal-forming method permits the production of parts with close tolerances and a minimum of scrap. It also enables the development of products that cannot be produced by any other method. By proper selection of powders, the powder metallurgy (P/M) specialist can control the density of products over a wide range and secure a wide range of mechanical and physical properties. He can produce mixtures of metals that are insoluble in each other or mixtures of metals and nonmetals that combine the properties of both.A ratio of at least 50% copper powder (by weight) would be required to result in a significantly metallic appearance. Higher ratios, up to the limit of pour-ability, will yield a more impressive metallic appearance and feel. D.N. lisson, "A Metallurgical Review of Plain Bearings," paper presented at Coppermetal Bearings Symposium, Melbourne, Australia, Oct. 29, 1969. The conditions of restrictions according to Article 67 and Annex XVII of the Regulation (EC) No 1907/2006 (REACH) for the manufacturing, placing on the market and use must be observed. With the exceptions that 0,66 kg of cupric oxide powder and 2,4 kg of 80-percent formic acid solution were used as starting materials and that the starting materials were mixed and stirred at 80 ° C 20 for hours, anhydrous copper formate crystals in an amount of 1,28 kg in same way as in example 1. The degree of thermal decomposition of the thus obtained anhydrous copper formate was practically 100%.

Source: A.K.S. Rowley, E.C.C. Wasser and M.J. Nash, "The Effect of Some Variables on the Structure and Mechanical Properties of Sintered Bronze," Powder Met. Int. 4(2):71 (1971). As apparent from the above description and as will be shown by the following Examples and Comparative Examples, the method of producing a fine copper powder by the thermal decomposition of anhydrous copper formate according to the present invention can provide a fine copper powder due to the use of the special anhydrous copper formate which has a small primary particle diameter and a low tendency to agglomerate. This particular anhydrous copper formate can be easily produced industrially at a low cost from a cheaper copper compound, and in this case, impurities contained in the starting material can be easily reduced. Porous bronze bearings are used widely in automotive service, household appliances, automatic machines and industrial equipment in two types of applications: The method of producing a fine copper powder according to the present invention involves thermally solid-phase decomposing anhydrous copper formate in a non-oxidizing atmosphere at a temperature ranging between 150 and 300 ° C to obtain a fine copper powder having an average primary particle diameter of 0,2 to 1 μm , having a specific surface area of ​​5 to 015 m2 / g and a low tendency to agglomerate, wherein the anhydrous copper formate is a waterless copper formate powder having a particle size of 850 μm or less, and 20 weight percent or more thermal decomposition within a temperature range of 90 to 160 ° C when the anhydrous copper formate powder is heated in a nitrogen or hydrogen gas atmosphere at a heating rate of 200 ° C / min. is heated. With a global market share of over 50%, GGP is the biggest producer of electrolytic copper powders in the world.

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The present invention will be explained in more detail with reference to the following examples and comparative examples, but the examples should not be construed as limiting the scope of the invention. In these examples, unless otherwise stated, all parts and percentages are based on weight. Generally, the major portion of the matrix is copper with about 5-15% low melting metal such as tin; 5-25% lubricant which may be lead, litharge, graphite, or galena; up to 20% friction material such as silica, alumina, magnetite, silicon carbide or aluminum silicide; and up to 10% wear-resistant materials such as cast iron grit or shot. The powder thus obtained, which was the product of thermal decomposition, showed a brown color, had an oxygen content of about 3%, and consisted of uniform nearly spherical primary particles having an average particle diameter of about 0,3 μm. The agglomerate particle diameter of the powder was measured (on average) after the powder was dispersed in water by the treatment with a mixer, and found to be about 15 μm. The crystals of the anhydrous copper formate obtained above were pulverized into a powder having a particle size of 150 μm (100 mesh) or finer, and using 1 kg of the powder, except that the powder was kept at 300 ° C for one hour thermal decomposition in the same manner as in Example 1. In this way, 414 g of a powder which was the product of thermal decomposition was obtained.

To 0,66 kg of cupric oxide powder, 2,4 kg of 16-percent aqueous formic acid solution was added. The resulting mixture was heated to 80 ° C for three hours, and the water was then removed by evaporation at 100 ° C at reduced pressure to concentrate and dry the reaction product to give 1,2 kg of anhydrous copper formate crystals. The degree of thermal decomposition of this anhydrous copper formate was 85%. The crystals thus obtained were dissolved in water to determine the content of water-insoluble components, and the content was found to be 15%. The water-insoluble components were analyzed by X-ray diffractometry and found to have a composition corresponding to an approximately 1: 1 mixture of unreacted cupric oxide and basic copper formate. P/M bronze filters are used to filter gases, oils, refrigerants and chemical solutions. They have been used in fluid systems of space vehicles to remove particles as small as one micron. Bronze diaphragms can be used to separate air from liquids or mixtures of liquids that are not emulsified. Only liquids capable of wetting the pore surface can pass through the porous metal part. For use for purposes such as applications in coating compositions, pastes and resins, on the other hand, in view of uniform dispersion and uniform coating, copper powder must be composed of powder particles which are finer, ie 10 μm or less, and uniform in shape. For use in electronic parts, copper powder having only an insignificant amount of alkali metals such as Na or K, sulfur and halogens such as Cl are preferable in view of prevention of corrosion and deterioration of electrical properties due to moisture. Source: P.W. Taubenblat, W.E. Smith and C.E. Evans, " Production of P/M Parts from Copper Powder," Precision Metal 30(4):41 (1972).

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The worldwide annual demand for ultrafine copper powder is 12-15 tonnes. However, a much larger amount of copper is used as a financing object. How much copper powder has disappeared into bank vaults worldwide and will probably never come out again, can not be verified. A basic attribute of powder metallurgy is the ability to combine materials in powder form that are otherwise immiscible. This unique advantage allows the production of friction materials in which copper and other metal powders are combined with solid lubricants, oxides and other compounds. Metallic friction materials can be operated at higher loads and temperatures than organic friction materials. The copper powder produced by the above-described method of the present invention is generally a fine copper powder having an average primary particle diameter between 0,2 and 1 μm, a specific surface area between 5 and 0,5 m² / g, and a low tendency to agglomerate. The salient feature of the fine copper powder obtained by the thermal decomposition of anhydrous copper formate according to the present invention is that the powder has little tendency to agglomerate as compared with the copper powders prepared by the reduction method and other conventional methods Has. For a lot number with a filling-code such as STBB0728K9, enter it as STBB0728 without the filling-code 'K9'. Very fine (325 mesh), highly pure irregular copper powder suitable for a range of applications including resin-casting, decorative coatings and powder metallurgy.