Alumina ceramics are of great industrial importance. With its high wear resistance, low thermal expansivity, low electric conductivity, they are widely used in abrasion-resistant liners and electronic circuit carrier substrate.
At present, a new material called ZTA (Zirconia-toughened Alumina) ceramic are now challenging the status of Alumina ceramic due to its super mechanical properties. As we all know, the mechanical properties of alumina strongly depends on the porosity and the grain size of the specimen. During the sintering process, the crystals reduce internal stress and undergo recrystallization without grain growth taking place. Voids form connected pore channels, which under ongoing sintering, break up to form discrete pores. This is also called the intermediate stage.
The crystal-structure under Electron Microscope showed the difference between ZTA (Zirconia-toughened Alumina) ceramic and Alumina ceramic under the same experimental condition. It is obvious that the crystal of ZTA ceramic is smaller and more uniform than common Alumina ceramics. That’s the reason why ZTA ceramic is better in density, hardness and wear resistance than Alumina ceramic.