Sintering Behaviors of Pt Nanopowders with Different Particle Sizes: A Real-Time Synchrotron X-ray Scattering Study

Abstract

We have studied the solid state sintering behaviors of platinum (Pt) nanopowders with different particle sizes using real-time synchrotron X-ray scattering in air. Pt powders with large particle size of 101 nm at room temperature (RT) showed a defect-free crystal domain size of 10 nm. Most of these powders exhibited multiple grains inside the particle. Solid state sintering of the powders mainly occurred through surface diffusion of Pt atoms near 145 °C, grain boundary diffusion from 150 to 400 °C, and then grain growth above 550 °C. Meanwhile, Pt nanopowders with small particle size of 18 nm at RT showed a crystal domain size of 8 nm. Most of these powders exhibited a single grain inside the particle. Solid state sintering of the nanopowders mainly occurred through surface diffusion of Pt atoms near 151 °C and then grain growth above 400 °C. Grain boundary diffusion does not happen because grain boundary hardly exists.