| The Al2O3 and Ag powders with nano-meter size were prepared by sol-gel method. The Al2O3 and Ag powders with different content of Ag were mixxed and milled by high-energy ball milling to be composite Al2O3/Ag powders. Systematical investigations were carried out on grain size and morphology of the Al2O3/Ag composite powder after high-energy ball milling by X-ray diffraction, and scanning electron microscope. Al2O3/Ag samples with the different content of Ag were prepared by cold pressing (CP) and vacuum sintering. The effect of sintering temperature and the content of Ag on the microstructure, density as well as properties of the Al2O3/Ag samples were investigated. The results indicated as the following.1. The grain sizes of Al2O3 and Ag prepared by sol-gel method were about 50nm. The size of some particles is above 50um due to the aggregation of nano-meter.2. The time of high-energy ball milling has effect on the size of Al2O3/Ag composite powders. The size of Al2O3/Ag composite powders decreased with increasing milling time and the size of Al2O3/Ag composite powders was about 5um after 5 hours milling.3. The sintering temperature has effect on the properties of Al2O3/Ag composite ceramic. The properties of Al2O3/Ag composite ceramic increased with increasing sintering temperature. After sintering at 1200℃for 2hrs, the fracture toughness,bending strength and hardness of Al2O3/Ag composite ceramic reached maximum.4. The fracture toughness and bending strength of Al2O3/Ag composite ceramic were increased due to the addation of Ag. The fracture toughness and bending strength of Al2O3/Ag increased with increasing the content of Ag from 0v% to 5v%. But as the content of Ag increasing from 5v% to 10v%, the fracture toughness and bending strength of Al2O3/Ag decreased due to the decreasing of density of Al2O3/Ag.5. The hardness of Al2O3/Ag composite ceramic decreased with increasing the content of Ag.6. The size of Al2O3/Ag composite powders has effect on the properties of Al2O3/Ag composite ceramic. The fracture toughness,bending strength and hardness of Al2O3/Ag composite ceramic increased with increasing milling time.7. Compared with common Al2O3 ceramic, the sintering temperature of Al2O3/Ag composite ceramic decreased about 200℃due to the existing of powders with nano scale.8. Ag doped in Al2O3 matrix can enhance Al2O3/Al2O3 grain strength. Compared with single phase Al2O3 ceramic, the fracture model of Al2O3/Ag composite ceramic changed from inter-granular fracture to trans-granular fracture.9. Ag doped in Al2O3 matrix increased the fracture toughness and decreased the hardness of Al2O3/Ag composite ceramic. The (H/KIC)2 of Al2O3/Ag-5v% reached 9. 62um-1.10. Compared with single phase Al2O3 and Alpha ceramic, the shearing strength between Al2O3/Ag-5v% composite ceramic and Alpha ceramic is greater.11. By three tests including acute haemolysis test, in vitro-toxicity test (MTT method) and acute sensitization test, the biocompatibility of the new material was preliminarily estimated. The negative results of these tests indicated that the material was safe for dental clinical application. |
PDF Full Text Request