The physical properties of pure copper in massive form are given in Table 3. Outstanding are the electrical and thermal conductivities which are markedly higher than those of any other base metal and are exceeded only by silver. A copper powder with a purity exceeding 99.95% is available, and, of course, the individual particles have the same properties as massive copper. However, it is impractical to achieve a density of 8.94 g/cm 1 by pressing and sintering alone, and, therefore, the properties of P/M parts are influenced by the density attained. Densification can be increased by additional operations such as double pressing-double sintering or forging, for example, and the properties of the P/M part approach those of the massive metal as a limit. Table 3. Physical Properties of Massive (Fully Dense) Copper This product is subject to the reporting requirements of section 313 of the Emergency Planning and Community Right to Know Act of 1986 and 40CFR372. 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. Impurities in the anhydrous copper formate (ppm) impurities in the produced Cu powder (ppm) washing liquids and technology impurities in the washed Cu powder (ppm)

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. Copper and copper alloy powders are also used in such nonstructural applications as brazing, cold soldering, and mechanical plating, as well as for medals and medallions, metal-plastic decorative products and a variety of chemical and medical purposes. Table of Contents: 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 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. Development of these bearings revolutionized the home appliance industry. By eliminating the requirement of periodic lubrication, the self-lubricating bearing assured many years of trouble-free operation of home appliances and led to a great expansion of the industry. New applications continue to be found and the self-lubricating bronze bearing industry consumes a major portion of the copper powder produced each year.

This product is not classed as dangerous goods for transport and can be shipped to all destinations without restriction.This powder was a fine copper powder consisting of nearly spherical primary particles uniform in size and having a uniform particle diameter of about 0,4 μm and having a specific surface area of ​​2 m² / g. 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 8 μm. Anhydrous copper formate produced by any of a variety of methods can be used in the present invention as far as the copper formate to be used satisfies the above requirements. However, anhydrous copper formate prepared by a method using copper carbonate, copper hydroxide or copper oxide as the starting copper compound and reacting this starting copper compound with formic acid or methyl formate is useful as a starting material for the process of the present invention when the process is industrial is performed. The anhydrous copper formate used in the present invention is generally copper (II) formate. The anhydrous copper formate is an anhydrous copper formate powder satisfying the thermal decomposition requirement that, when the powder is contained in an amount of 10 mg in a nitrogen or hydrogen gas atmosphere at a heating rate of 3 ° C / min. is heated, 90 weight percent or more of the powder within a temperature range of 160 to 200 ° C are thermally decomposed. This thermal decomposition behavior is preferable from the viewpoint of obtaining a fine copper powder which has higher purity and less tendency to agglomerate. In view of obtaining a copper powder having a smaller agglomerate particle size, the anhydrous copper formate powder has a particle size of 850 μm (20 mesh) or finer, and especially a powder having a particle size of 150 μm (100 mesh or finer). Such an anhydrous copper formate powder can be obtained by dehydrating copper formate hydrate at a temperature of 130 ° C or less, and then pulverizing the dehydrated copper formate by forming crystals of anhydrous copper formate directly from an aqueous solution of copper formate and then pulverizing the crystals, or by directly forming a crystalline anhydrous copper formate powder having a particle size of 850 μm (20 mesh) or finer from an aqueous solution of copper formate. It is preferable that the anhydrous copper formate powder thus obtained has a low content of impurity elements, especially alkali metals such as Na or K, sulfur and halogens such as Cl, for the purpose of producing a fine copper powder having a reduced impurity content. This powder was a fine copper powder having an oxygen content of 0,4% or less, consisting of nearly spherical primary particles uniform in size and having an average particle diameter of about 0,3 μm, and having a specific surface area of ​​3 m² / g would have. P/M friction materials are used as clutches and brakes. Dry applications may include both, but wet applications are normally confined to clutches. For brake and clutch facings, powders having high green strength are essential. Such powders characteristically also have high internal porosity, low apparent density and irregular shapes.