科研之友
微信
新浪微博
Facebook
分享链接
摘要
Aluminum oxynitride (AlON) powders were synthesized by carbothermal reduction and nitridation process using alpha-Al2O3 powder as starting material. Activated charcoal powder and submicron carbon powder were mixed with alpha-Al2O3 respectively to vary nucleation density of AlON. Influence of nucleation density on phase assemblages, morphology of AlON powders and transparence of AlON ceramics were studied. Single phase AlON powders were synthesized after holding at 1750 degrees C for 60 min with for both mixture powders of different nucleation density. The results show that the synthesized powders exhibit different morphology and milling property. The AlON powder synthesized by alpha-Al2O3 and activated charcoal mixture show irregular shape, loose structure and small particle size, due to its high nucleation density. Moreover, it is easier to mill the obtained AlON powder into small particle (0.93 mu m). However, for the AlON powder synthesized by mixture of alpha-Al2O3 and submicron carbon powder, their grain grow obviously during the synthesis of the AlON powder, due to its low nucleation density with large near sphere particles close to 2.13 mu m in diameter. Therefore, nucleation density plays a key role in controlling morphology, structure characteristics and milling performance of the AlON powders. Using the AlON powder synthesized by high nucleation density powders, high transparent AlON ceramics was fabricated by pressureless sintering at 1880 degrees C for 150 min, the maximum transmittance was similar to 76.5% (3 mm in thickness). It is 48.3% higher than that using AlON powder synthesized by low nucleation density powders. Therefore, for using alpha-Al2O3 as starting material to prepare AlON powder, high nucleation density is beneficial to AlON powder with small particle size and high sintering ability, which contributes to the high transmittance of AlON ceramics.
- 出版日期2018-4-20
- 单位大连海事大学; 中国科学院理化技术研究所
