Sintering Kinetics Analysis of Molybdenum Nanopowder in a Non-Isothermal Process

Abstract

Compared with commercial micro-sized molybdenum powder, the sintering of molybdenum nanopowder fabricated by high-energy ball milling and subsequent hydrogen reduction was considerably more activated due to its extended surface area. In this study, the sintering kinetics of a molybdenum nanopowder were evaluated by measuring the linear shrinkage in a non-isothermal process and calculating the activation energy for the initial sintering stage. To reach a linear shrinkage of 2 %, the activation energy of the molybdenum nanopowder sintering was 180 kJ, primarily due to the grain boundary diffusion, while the activation energy of the commercial micro-sized powder sintering was 345 kJ, predominantly due to the volume diffusion.