Analysis of particles size distribution on the agglomeration and shrinkage of alumina-zirconia compacts

The combination of Alumina and Zirconia has emerged as a promising ceramic structure for advance machine tool application. However, the particles of Alumina and Zirconia tend to agglomerate during mixture which affected shrinkage and dimension accuracy of the end product. This study focused on the analysis of the particle size of Alumina-Zirconia compacts and their relationship with the shrinkage and agglomerates. The particles size of single Alumina, Zirconia and ball-milled Alumina-Zirconia with 90-10 wt% ratio were examined by mastersizer. These powders then were compacted and sintered at 1400°C to examine their shrinkage. The results show that Alumina possesses larger particles size of 109.65 μm, which is 10 folds larger than Zirconia at 6.10 μm. When blended by ball mill, the Alumina�Zirconia particles were changed into 9.77 μm, showing that the ball mill to refine powder particles while reducing the risk of agglomeration. After sintering, the Alumina-Zirconia compacts were shrunk to maximum 9.56% when 75-25 wt% of Alumina-Zirconia. The combination of porosity, agglomerate and infiltration of zirconia between alumina grains were responsible for the shrinkage of Alumina-Zirconia compacts

Effect of sintering temperature on density, hardness and tool wear for alumina-zirconia cutting tool

Combination of alumina (Al2O3) and zirconia (ZrO2) as cutting tool have been established themselves as a dominant in ceramic category for dry machining. The mechanical properties of Al2O3-ZrO2 cutting tool were critically dependent on its density and hardness, which affected by the powder preparation and sintering processes. This paper present the effect of sintering temperature on density, hardness and tool wear of Al2O3-ZrO2 cutting tool. Specific composition of 80-90 wt% Al2O3 and 10-20 wt% ZrO2 powders were mixed and ball milled for 12 hours. These powders then were compacted in the form of RNGN120600 designated cutting tool by using manual hydraulic press before undergone secondary compaction by Cold Isostatic Press. The compacted powders then were sintered from 1200oC to 1400oC at constant 9 hours soaking time. For each sintered cutting tool, evaluation has been made based on the density and hardness. By using AISI 1045 as a workpiece material, the wear performance of the selected cutting tools were evaluated within 200-350 m/min cutting speeds, 0.1 mm/rev feed rate and 0.5 mm depth of cut. The results shows that the sintering temperature at 1400oC and 9 hours soaking time produced maximum relative density and hardness for 90 wt% Al2O3 and 10 wt% ZrO2 at 94.17% and 63.4 HRC respectively. Cutting tool contained with 80 wt% Al2O3 and 20 wt% ZrO2 contributed maximum relative density of 97% and hardness of 70.07 HRC. Maximum tool life recorded was 156s at 200 m/min cutting speed. Wear mechanisms of fabricated cutting tool dominated by the notch and flank wear at the early stage of machining and formation built up edge at the end of machining process