Effects of heating rate on densification and grain growth during field-assisted sintering of alpha -Al sub 2 O sub 3 and MoSi sub 2 powders

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Vol. 32A; no. 10; pp. 2633 - 2638
• Main Authors: Stanciu, L A, Kodash, V Y, Groza, J R
• Format: Journal Article
• Language: English
• Published: 01.10.2001
• ISSN: 1073-5623

Two types of powders, electrically conductive MoSi sub 2 and insulating alpha -Al sub 2 O sub 3 , were sintered by a field-assisted sintering technique (FAST) using heating rates from 50 deg C to 700 deg C/min. The Al sub 2 O sub 3 powders were sintered to 99 pct density at 1100 deg C for 2 minutes under 45 MPa pressure. For Al sub 2 O sub 3 , no exaggerated grain growth was observed and the final grain size inversely scaled with the heating rate. Such a grain growth behavior fits the literature models based on multiple transport mechanisms for constant-heating-rate sintering. The density reached by MoSi sub 2 under similar sintering conditions was 91 pct. The grain size was independent of the heating-rate value. Specific electrical field and pressure effects are shown to contribute to enhanced densification and minimal coarsening in each material.