Sandvik Ab

Rolf Svensson

Mats G Waldenstrom

Mats Waldenstr&ouml;m

One or more metal salts of at least one iron group metal containing organic groups are dissolved in at least one polar solvent and complex bound with at least one complex former comprising functional groups in the form of OH or NR , (R&boxH;H or alkyl). In addition, at least one insoluble, reducible salt of at least one iron group metal is suspended in the solution. Hard constituent powder and, optionally, a soluble carbon source are added to the solution. The solvent is evaporated and the powder mass is heat treated in inert and/or reducing atmosphere. As a result, a powder mixture is obtained which, after addition of a pressing agent, can be compacted and sintered according to standard practice to form a body containing hard constituents in a binder phase.

Method of making metal composite materials

One or more organic or inorganic metal salts or compounds of at least one of the groups IV, V and VI of the periodic system, particularly V, Cr, Mo and W, optionally together with one or more organic iron group metal salts, are dissolved in at least one polar solvent and complex bound with at least one complex former comprising functional groups in the form of OH or NR.sub.3, (R=H or alkyl). Hard constituent powder and optionally soluble carbon source are added to the solution. The solvent is evaporated and the remaining powder is heat treated in an inert and/or reducing atmosphere. As a result, coated hard constituent powder is obtained, which after addition of a pressing agent and optionally with other coated hard constituent powders and/or carbon to obtain the desired composition, can be compacted and sintered according to standard practice.

The present invention relates to an etching process for the purpose of removing binder phase from the surface of a hard metal consisting of hard material in a binder phase based on cobalt and/or nickel. By carrying out the etching process electrolytically in a mixture containing concentrated sulfuric acid and concentrated phosphoric acid at a volume ratio of 0.5-2 with a water content of &lt;50% at a temperature of 25.degree.-60.degree. C. an even binder phase removal without deep penetration is achieved.

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Hagersten, Sweden

Rolf Svensson