Abstract: Process for the production of particulate ruthenium with a purity of ?99.99 wt. % and a specific surface area of 0.2-0.5 m2/g, comprising: (1) providing a hydrochloric solution prepared by dissolving RuO4 in hydrochloric acid and has a content of ruthenium in the form of dissolved ruthenium species of 15-22 wt. %; (2) providing an aqueous solution with an ammonium chloride content of 200-600 g/litre; (3) forming a reaction mixture by dosing the hydrochloric solution provided in step (1) to the aqueous solution provided in step (2) at a molar ratio of 1 mol ruthenium: 3-6 mol ammonium chloride, at a temperature of 55-90° C. over the course of 0.2-5 hours and while adjusting and maintaining a pH of ?0.6 to 0; (4) separating solid material formed during step (3) from the hydrochloric reaction mixture; and (5) calcinating the solid material separated in step (4) at an object temperature of 350-1,000° C.

Abstract: Provided is a method for producing a metal sintered body. The method for producing a metal sintered body in accordance with an embodiment includes (a) disposing a metal powder in a chamber of a spark plasma sintering apparatus, (b) applying a electric current to the metal powder to raise a temperature inside the chamber from a standby temperature to a first sintering temperature, (c) lowering the temperature inside the chamber to a second sintering temperature lower than the first sintering temperature and performing sintering, and (d) lowering the temperature inside the chamber from the second sintering temperature to the standby temperature.