欧美电影一区二区三区,岛国片免费在线观看,97色网欧美精品久久,亚洲欧洲日产国码?v系列天堂

熱線:021-50550642
TECHNICAL ARTICLES

技術(shù)文章

當(dāng)前位置:首頁技術(shù)文章不同操作條件下氧化鋁燒結(jié)對致密化的影響

不同操作條件下氧化鋁燒結(jié)對致密化的影響

更新時(shí)間:2016-07-15點(diǎn)擊次數(shù):3013

Nearly pure -alumina samples produced by uniaxial pressing were flash sintered under electrical fieldsranging from 500 V/cm to 1500 V/cm in experiments at constant heating rate. Sintering temperature sig-nificantly decreased with the applied E-field even down to ≈900?C at 1500 V/cm. The onset temperaturefor flash sintering can be successfully modelled as a function of the applied voltage. The sintering temper-ature is also shown to be strongly affected by the electrode materials used during the treatment: usingsilver or carbon electrodes the sintering temperature is about 300?C lower than when using platinumelectrodes. In addition, the bulk density and porosity of the sintered alumina ceramic correlate stronglywith the imposed current limit. Power dissipation was analysed before and during flash sintering; theactivation energy for conduction was calculated in both cases, indicating that the process is based onionic diffusion phenomena. Finally, we showed that during flash sintering the activation energy for con-duction decreases, suggesting the occurrence of physical or structural modifications induced by currentlocalization at the grain boundaries.