Modelling of High-Power Grinding for Sintering Activation of Silicon Nitride Powders

Abstract

The influence of milling conditions (acceleration of milling bodies, ball milling time and medium) on specific surface of silicon nitride powders and iron content in them has been studied in the paper. The sintering kinetics of the samples being prepared from the produced silicon nitride powder with various sintering additions has been also investigated. Post-sintering density and micro-hardness have been selected as optimization parameters in the given case.

It has been revealed that it is possible to reach high powder dispersivity during 10... 15 min at ball milling of silicon nitride powder in a planetary and centrifugal mill with acceleration of milling 20g and 40g bodies. The grinded powders are characterized by high activity that makes it possible to obtain highly dense (96.. .98 %) samples on the basis of silicon nitride during subsequent pressing and sintering processes.

The obtained regression equations allow to select optimum conditions for silicon nitride powder production and samples made of them with high values of density and hardness.