Abstract:

Objective The objective of this study is to investigate the influence of mechanical properties and sintering performance by adding 5% weight percentage aids to nano-compound zirconia toughened alumina（ZTA） ceramics. Methods Micrometer Al2O3 and nanometer ZrO2（quality ratio 4 ∶ 1） were used to get 55% volume percentage slurry. Magnesium oxide and titanium oxide were taken as aids which were 5% weight percentage of the Al2O3 and ZrO2 powder. Five groups（number 0, 1, 2, 3, 4 group） were divided according to different proportion of aids. After gel-casting, the porcelain pieces were sintered at 1 150, 1 200, 1 300, 1 400, 1 450, 1 500, 1 600 ℃ for 2 hours. Static three-point flexure strength, line shrinkage, relative density were measured and scanning electron microscopy（SEM） was used to observe section. Results Number 1（MgO 1%, TiO2 4%） group had the highest bending strength. It was （401.78±19.50）MPa after sintering at 1 600 ℃ for 2 hours and was higher than 0 group （380.64±44.50）MPa. Bending strength became lower than 0 group when MgO was more than 2% or more than that weight percentage of ZTA powder. When MgO content was higher than 2% or more than that weight percentage, there was no difference in relative density raising rate between each sintering assistants groups. When the sintering temperature was higher than 1 200 ℃, all groups showed obvious line-shrinkage and the groups which contained sintering assistants were all was higher than 0 group. Conclusion Adding MgO and TiO2 aids from 1% to 4% weight percentage of ZTA will promote fritting and increase ZTA nano -compound ceramics mechanical properties. Adding 2% MgO aids or more than that weight percent will has no obvious help to increase the relative density raising rate of ZTA nano -compound ceramics and will degrade the mechanical properties of ZTA nano-compound ceramics.

Key words: zirconia toughened alumina ceramics, gel-casting, nano-compound ceramics