Abstract: The present invention relates to a method of adding a grain growth inhibitor of WC/Co cemented carbide, which comprises adding a water-soluble salt of V, Ta, or Cr component as a grain growth inhibitor, at the time of mixing water-soluble salts of W and Co during the initial production process of WC/Co cemented carbides. As a result, the present invention leads to the production of powder of homogeneous distribution of grain growth inhibitors, which in turn results in the enhancement of the mechanical properties thereof by effectively controlling the abnormal growth of WC during sintering in the production process of said cemented carbides.

Abstract: The present invention relates to a method of producing nanophase Cu—Al2O3 composite powder by means of 1) the producing precursor powders by centrifugal spray drying process using the water base solution, in which Cu-nitrate (Cu(NO3)23H2O) and Al-Nitrate (Al(NO3)39H2O) are solved to the point of final target composition (Cu-1 wt %/Al2O3),2) the heat treatment process (desaltation process) at the 850° C. for 30 min in air atmosphere to remove the volatile components such as the moisture and NO3 group in precursor powder and simultaneously to synthesize the nano CuO—Al2O3 composite powders by the oxidation of corresponded metal components and 3) the reduction heat treatment of CuO at 200° C. for 30 min in reducing atmosphere to produce the final nanophase Cu—Al2O3 composite powders with the size below 20 nm.

Abstract: The present invention relates to a method of producing paste containing flaky aluminum powder, which is the main ingredient of the topcoat paint for automobiles. The present invention is intended to provide a production method, which is more economical than the conventional method of using the gas-atomozied powders. In particular, a vessel is charged with by-product scraps from the production process of aluminum foil, balls, mineral spirits, and an unsaturated fatty acid, such as oleic acid. Under such conditions, the ball-milling is carried out to yield an intermediate paste containing flaky aluminum powder, which is then made into aluminum paste by adjusting the amount of a solvent.

Abstract: The present invention relates to a method of producing nanophase WC/TiC/Co composite powder by means of a mechano-chemical process comprising a combination of mechanical and chemical methods. For this purpose, the present invention provides a method of producing nanophase WC/TiC/Co composite powder, said method comprising as follows: a process of producing an initial powder by means of spray-drying from water-soluble salts containing W, Ti, and Co; a process of heating to remove the salts and moisture contained in the initial powder after spray-drying; a process of mechanically ball-milling to grind oxide powder after removing the salts and moisture therefrom, and to homogeneously mix the powder with an addition of carbon; and a process of heating the powder after milling, for reduction and carburization, in an atmosphere of reductive gas or non-oxidative gas.

Abstract: A mechanochemical process for producing fine WC/Co composite powder which is so small in WC grain size and in mean free path, and contains such a uniform distribution of WC and Co that its hard metal is superior in strength, compressive strength, TRS and wear resistance and considerably free of impurities. The method comprises the steps of drying an ammonium metatungstate--Co(NO.sub.3).sub.2 solution in a spray dry manner to give initial powder of porous spheroids or in a common manner to give a cake of initial powder, removing the salts and humidity from the initial powder by a thermal treatment, mixing and milling the desalted initial powder with carbon black, and subjecting the mixed powder to reduction/carburization in a reactor.

Abstract: A method for producing high density and ultrafine W/Cu bulk material by a mechano-chemical process is disclosed. In the method of this invention, metal salts as start materials are spray-dried and prepare W--Cu precursor powder having uniformly-dispersed tungsten and copper components. The W--Cu precursor powder in turn is subjected to a desalting and milling process, thus preparing W--Cu oxide composite powder. Thereafter, the W--Cu oxide composite powder may be formed into a formed green body prior to reducing and sintering under hydrogen atmosphere.

Abstract: A new carbothermic reaction process is described for the thermochemical processing of nanophase WC-Co powders. The process permits shorter reaction times, reduced temperatures, and finer microstructures compared to conventional processing methods.The process builds on our experience with spray conversion processing [1], but involves 1) chemical vapor infiltration reaction of the carbon infiltrant and particle substrate to from WC-CO; and 2) removal of any excess (unreacted) carbon by controlled gasification. A feature of the carbothermic reaction process is its adaptability to conventional WC-Co processing technology, as well as to spray conversion processing technology.The resulting power particles consist of a network of fine grains, (less than 100 nm) of WC and Co with interconnected fine porosity. Powder particles suitable for subsequent handling and consolidation are readily produced with diameters greater than 10 microns.

Abstract: A new carbothermic reaction process is described for the thermochemical processing of nanophase WC-Co powders. The process permits shorter reaction times, reduced temperatures, and finer microstructures compared to conventional processing methods.The process builds on our experience with spray conversion processing but involves 1) chemical vapor infiltration reaction of the carbon infiltrant using a carbon source gas at a carbon activity greater than or equal to 1.0 with the particle substrate to form WC-CO; and 2) removal of any excess (unreacted) carbon by controlled gasification using a gas with carbon activity less than 1.0. A feature of the carbothermic reaction process is its adaptability to conventional WC-Co processing technology, as well as to spray conversion processing technology.The resulting power particles consist of a network of fine grains, (less than 100 nm) of WC and Co with interconnected fine porosity.