Characteristics of Cordierite-ZrO₂ Composites Fabricated by The Multiphasic Sol-Gel Route

Abstract

Based on the electrokinetic properties of aqueous silica, boehmite, and ZrO2 dispersions, cordierite-ZrO2 composites were fabricated by the multiphasic sol-gel (or nanometer-scale sol mixing) route. The average particle sizes of boehmite and ZrO2 used in this study are 70 nm and 40 nm, respectively. The fabricated composites were characterized by a dense and homogeneous microstructure and by a uniform spatial distribution of submicron-sized tetragonal ZrO2 particles (200 nm) throughout the matrix. The microstructure of the matrix was represented by small-sized grains (< 400 nm) with a highly uniform grain-size distribution. The enhanced fracture toughness with increasing ZrO2 content was partly attributed to the martensitic t → m transformation. The formation of detrimental zircon (ZrSiO4) was avoided by suitably adjusting the heating schedule during sintering.