Powder distribution on powder injection moulding of ceramic green compacts using thermogravimetric analysis and differential scanning calorimetry

Abstract

Powder-binder separation during injection moulding causes defects such as cracking, warpage or anisotropic shrinkage during firing. In this paper, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) have been previously used to analyse powder distribution within the green body for metal injection moulding are used for ceramics. TGA and DSC are used to characterize the mass loss and heat of fusion of the binder system, silicon nitride feedstock and test-bars. TGA can measure the volume fraction of powder in green parts directly with 1.76vol% difference from nominal volume fraction and variations up to 0.177vol%. The DSC empirical model predicted volume fraction of powder in green parts with 1.76vol% difference from nominal volume fraction and variations up to 1.710vol%. Using rule of mixture, it over predicted volume fraction of powder in green parts by 6.78vol% from nominal volume fraction and with variations up to 2.510vol%.