Surface Properties Modification of Zirconia Toughened Alumina by Using Titania Additives

Abstract

Aluminium oxide (Al2O3) were mixed with multicomponent such as Zirconia (ZrO2) and Titania (TiO2). The aim of this thesis was to investigate the effect of TiO2 addition to Zirconia Toughened Alumina (ZTA). The physical, mechanical and microstructural behavior was characterized in this research. The percentage of Alumina was 83-85% and Zirconia used a fixed percentage of 15% for all samples where the percentages of Titania were used 0-1.5%. Each composition was weighted, mixed in pot mill with alcohol medium, heated, again mixed with polyvinyl alcohol binder and pressed using hydraulic press under 160 MPa into 10 mm pellets. The pellets were pre-sintered at 600°C for 2 hours and then sintered at 1450°C under pressureless condition. Bulk density, porosity and other properties of the samples were measured using standard procedure. Vickers hardness and fracture toughness of the sintered samples were measured using the Vickers indentation method. Phase analysis and microstructural analysis were carried out by XDR and SEM. By comparing ZTA ceramics with and without addition of MgO and TiO2 the results found an increasing of fracture toughness and hardness of the materials. The XRD patterns of ZTA samples containing 15 wt% of ZrO2, 0.5-1.5 wt% TiO2 and sintered at 1450°C for 2 hours indicated that α-Al2O3, t -ZrO2, and TiO2 are the crystalline phases present in the composite samples. The microstructures show highly homogeneous microstructures without agglomerates, pores or abnormally grown alumina grains with less porosity when compared to only Zirconia Toughened Alumina. The approach adopted in the present study may provide an alternative to design Al2O3-ZrO2-TiO2 composites with improved mechanical properties.