This product is not classed as dangerous goods for transport and can be shipped to all destinations without restriction. 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. The washing liquids and the washing technique for each copper powder shown in the table 3 are as follows. All components of this product are listed in the U.S. Environmental Protection Agency Toxic Substances Control Act Chemical substance Inventory. 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 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 The anhydrous copper formate crystals obtained above were subjected to thermal decomposition in the same manner as in Example 2 and then cooled to room temperature. D.N. lisson, "A Metallurgical Review of Plain Bearings," paper presented at Coppermetal Bearings Symposium, Melbourne, Australia, Oct. 29, 1969. Some of the most widely used general purpose high purity copper powders are listed bellow. Specifications are based on a typical analysis. A Cu-25Pb-3.5Sn alloy is used widely for such applications as cam bearings, turbine bearings, pump bushings and high speed thrust washers.

Share on:

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). Suitability of gloves should be determined both by material and quality, the latter of which may vary by manufacturer.

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. EPA-D: Not classifiable as to human carcinogenicity: inadequate human and animal evidence of carcinogenicity or no data are available. Self-lubricating porous bronze bearings depend on conduction and convection for heat dissipation during service. The frictional heat developed is proportional to PVµ where P is the pressure on the bearing, V is the surface velocity and µ is the coefficient of friction. Practical limits for safe operation of these bearings are often set at a PV factor of 50-60 ksi (345-414 MPa). These bearings are installed by pressing into rigid reamed or bored housings. Different copper powders vary based on the production method, purity, particle size, particle shape, apparent density, conductivity, color and flow rate. Source: A. Price and J. Oakley, "Factors in the Production of 90/10 Tin Bronze Compacts of Higher Density (7.49g/cm 3)," Powder Met. 8:201 (1965).Aluminum bronze P/M parts containing from 5% to 11% aluminum are prepared from blends of the elemental powders. Alloys containing from 5% to 9% aluminum are single-phase materials and have excellent ductility. They can be strengthened by cold working. Alloys containing from 9% to 11% are two-phase materials which are less ductile than the alloys of lower aluminum content. However, they can be heat treated to increase their strengths. 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. The powder thus obtained, which was the product of thermal decomposition, showed a copper color and consisted of uniform nearly spherical primary particles having an average particle diameter of about 0,3 μm. However, the powder became brown within a relatively short time. In addition, 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 20 μm. 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. 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.