Effect of binders on microstructural and mechanical properties of sintered alumina

Abstract

This study examines the effects of organic binder content, plasticity and sintering temperature on the microstructural and mechanical properties of sintered samples prepared from alumina spray-dried powders. Measurements of mechanical strength of sintered samples prepared from spray-dried alumina powders containing the two binders polyvinyl alcohol (PVA) or polyethylene glycol (PEG) are reported. This analysis revealed that the introduction of an optimal amount of binder in the composition of spray dried powders enhances the relative density and the mechanical strength of sintered samples prepared from these powders. The variation of mechanical strength of these samples with sintering temperature is compared to those prepared from alumina with no additive and discussed. For powders containing PVA as a binder, the samples' properties are better when the amount of PVA is lower. It was also observed a good deformability of alumina granules spray dried with the PEG binder which leads to get more homogeneous microstructure and therefore a good sintering and densification of samples. ► Binder and sintering temperature affect the microstructural and mechanical properties of alumina. ► Binder enhances the relative density and the mechanical strength of sintered samples. ► The properties of samples containing PVA are better when the amount of PVA is lower. ► We note a good sintering and densification of samples prepared with PEG binder.