Improved Dispersion of Micron-Sized Platinum Powder through Heat Treatment

The agglomeration of micrometer-sized platinum particles prepared by chemical liquid-phase reduction results in inadequate dispersion, a wide particle size distribution, and low tap density, thereby impacting the application of the platinum powder. In this study, CaO and platinum powder were homogeneously mixed through ball milling and subsequently subjected to heat treatment at temperatures ranging from 700 to 1300 °C. Following treatment at 1100 °C, the particle size distribution of platinum became narrower with SD (<i>D</i> ₉₀-<i>D</i> ₁₀) decreasing from 14.5 to 3.23 μm, while the tap density increased by 76% compared to pretreatment levels. These findings suggest that barrier-heat treatment effectively prevents sintering and agglomeration of platinum powder. During heat treatment, atomic and grain boundary diffusion facilitated the dispersion of the platinum powder within the CaO matrix, leading to grain coarsening, densification of particle structure, improved dispersion properties, and increased tap density with a narrowed particle size distribution. This paper presents a novel method for preparing a high-performance platinum powder.