Process for the production of metallic powders, powders thus prepared and compacts including these powders

摘要

Metal powder preparation comprises reduction or decomposition and reduction of acicular metal oxalate particles of specified aspect ratio and length. Metal or alloy powder preparation comprises producing acicular metal oxalate particles having a length/diameter ratio of 4-20 and a length of 5-10 micro m and then either reducing the oxalate with hydrogen gas or decomposing the oxalate in air to an oxide and then reducing the oxide. Independent claims are also included for the following: (i) a metal or alloy powder comprising spongy or filamental grains prepared by the above process; (ii) iron powder with a spongy or filamental microstructure and having a total iron content of≥98%, an elementary iron content of≥95.7%, a hydrogen loss of≤1.3%, a specific surface of≥0.50 m<2>/g, a Fischer sub-sieve size of 3.25-3.5 micro m, a sieved particle size of more than 70% -45 micro m and≥1% +150 micro m, and a green force (at 276 MPa molding pressure) of≥50 MPa; (iii) a compact produced by pressing the above powder; (iv) a hard or soft (ferro)magnetic material comprising the above compact or the above powder; (v) a porous electrode comprising the above compact; (vi) a catalyst support comprising the above compact; (vii) a mechanical part comprising the above compact; (viii) a pyrotechnic heating composition comprising the above iron powder; (ix) a pellet of the above pyrotechnic heating composition; and (x) a thermal pile comprising the above pellets.