Corrosion and mechanical behaviour of Al2o3.Tio2 composites produced by spark plasma sintering

Abstract

Al2O3.TiO2 ceramic composites exhibit versatile properties such as high hardness and excellent wear, chemical, thermal and corrosion resistance. As such, they have been used in various applications such as optical and electronic, gas separation, biomedical processes, and support for transition metal catalysts, wear resistant coatings in machinery, textile and printing industries. However, alumina and alumina-based composites often exhibit high brittleness which limits their potential application as a structural material. In this work, TiO2 and Al2O3 powders at varying compositions were produced through spark plasma sintering (SPS) technique to form Al2O3.TiO2 composites. This study investigated the mechanical and anti-corrosion performances of Al2O3.TiO2 composites produced by SPS. A higher content of TiO2 (15wt%) resulted in a lower Vickers's hardness, thus counteracting the intrinsic brittleness in Al2O3. Wear resistance also improved with an increase in TiO2 content up to 10wt%. However, at 15wt% TiO2, wear resistance decreased due to low hardness. In the sintered samples, secondary phase Al2TiO5 was detected and its concentration increased with an increase in TiO2 content. The microstructure was well reinforced and uniformly. The corrosion resistance in 35 g/l of NaCl solution improved with an increase in the TiO2 content of up to 10wt%. However, at 15wt% TiO2, corrosion resistance decreased due to the formation of the secondary phase, Al2TiO5.