Abstract: The aim of the present invention is to provide a metal powder for an electroconductive paste with which a low-resistance electrode film can be formed. One embodiment of the present invention relates to a platinum-containing or platinum-alloy-containing metal powder for an electroconductive paste, the metal powder including a metal element or metal elements other than Pt, wherein the metal elements other than Pt include at least Ca, and may further include Al and Zr, and the total content of the Ca, Al and Zr among the metal elements other than Pt is 10-900 mass ppm.

Abstract: The present invention relates to a method for producing a platinum-based alloy powder, the method comprising a heat treatment of a mixed powder containing a platinum-based powder composed of at least one selected from the group consisting of platinum and platinum compound, a platinum group metal-based powder composed of at least one selected from the group consisting of iridium, rhodium, palladium, and compound containing at least one of them, and an alkaline-earth metal compound, wherein specific surface area of the platinum group metal-based powder is 30 m2/g or more and D90 of the mixed powder is 1.0 ?m or less. According to the method for producing a platinum-based alloy powder of the invention, it is possible to produce a platinum-based alloy powder that has a desired particle diameter, also has a sharp particle size distribution, and has high purity and crystallinity.

Abstract: The present invention provides a process for producing a noble-metal powder, the process being capable of producing, at low cost, a noble-metal powder having a narrow particle-size distribution range, high purity and high crystallinity. The present invention relates to a process for producing a noble-metal powder and including a step in which an acidic aqueous solution of both one or more noble-metal compounds and a calcium compound is prepared, a step in which the acidic aqueous solution is added to a basic aqueous solution to yield one or more oxides or hydroxides of the noble metal(s) or a mixture of two or more thereof and yield a calcium hydroxide, a step in which the oxides or hydroxides of the noble metal(s) or the mixture is reduced with a reducing agent, and a step in which a solid matter including a reduced form of the noble metal(s) is separated and heat-treated.

Abstract: The present invention provides a process for producing a noble-metal powder, the process being capable of producing, at low cost, a noble-metal powder having a narrow particle-size distribution range, high purity and high crystallinity. The present invention relates to a process for producing a noble-metal powder and including a step in which an acidic aqueous solution of both one or more noble-metal compounds and a calcium compound is prepared, a step in which the acidic aqueous solution is added to a basic aqueous solution to yield one or more oxides or hydroxides of the noble metal(s) or a mixture of two or more thereof and yield a calcium hydroxide, a step in which the oxides or hydroxides of the noble metal(s) or the mixture is reduced with a reducing agent, and a step in which a solid matter including a reduced form of the noble metal(s) is separated and heat-treated.

Abstract: The present invention relates to a method for producing a platinum-based alloy powder, the method comprising a heat treatment of a mixed powder containing a platinum-based powder composed of at least one selected from the group consisting of platinum and platinum compound, a platinum group metal-based powder composed of at least one selected from the group consisting of iridium, rhodium, palladium, and compound containing at least one of them, and an alkaline-earth metal compound, wherein specific surface area of the platinum group metal-based powder is 30 m2/g or more and D90 of the mixed powder is 1.0 ?m or less. According to the method for producing a platinum-based alloy powder of the invention, it is possible to produce a platinum-based alloy powder that has a desired particle diameter, also has a sharp particle size distribution, and has high purity and crystallinity.