PLATINUM POWDER FOR MAGNETIC MATERIAL TARGET, METHOD FOR PRODUCING THE POWDER, METHOD FOR PRODUCING MAGNETIC MATERIAL TARGET COMPOSED OF PLATINUM SINTERED COMPACT, AND THE SINTERED MAGNETIC MATERIAL TARGET

摘要

Disclosed is a platinum powder for magnetic material targets, which has a particle size distribution of 0.1-5 µm. The impurities contained in the platinum powder for magnetic material targets are limited as follows: sodium, potassium and calcium contents are all less than 20 wt ppm; hydrogen and chlorine contents are respectively less than 500 wt ppm; carbon, nitrogen and oxygen contents are respectively less than 1000 wt ppm; and the other impurities are respectively less than 10 ppm, and less than 100 ppm in total. The platinum powder contains little impurities and can be obtained at low cost. A material suitable for production of a magnetic recording medium can be obtained by using a high-purity sputtering target produced from the platinum powder.