Electric current assisted sintering of AlN ceramics: thermal conductivity and transparency

Abstract

Densification, thermal conductivity and transparency of aluminium nitride ceramics densified by electric current assisted sintering are reviewed. Aluminium nitride powders could be densified without any sintering additives by electric current assisted sintering. Sintering additives, Y₂O₃ or CaF₂, and others are effective for densification, increase in thermal conductivity and transparency. As a result of the reaction with the sintering additives and oxide on the surface of the AlN powder, a secondary phase forms between AlN grains, oxygen impurity between aluminium nitride grains decreases and thermal conductivity increases. These mechanisms are effective in the sintering of aluminium nitride ceramics densified by electric current assisted sintering, though sintering time is short, within 5 min. The secondary phase formation does not always give good effect for transparency.     

奥利维尔·加尼尔——法国新巴洛克主义设计的奠基人

法国设计大师奥利维尔·加尼尔以奢华的工艺或材料结合简约的设计风格折衷了巴洛克艺术与新古典艺术,而成为了新巴洛克艺术的奠基人。这一地位的确立既取决于其家庭环境的影响和其自身对传统工艺孜孜不倦的追求,同时也取决于法国上流社会审美倾向的历史性流变。     

泰特现代

泰特现代艺术博物馆自从扩迁驻入原由斯科特设计的伟岸的河岸电厂内后,不仅使近现代的国际艺术品有了新的栖身之所,而且改建后的泰特现代所吸引的如潮的人流,极好地证明了其无论对于艺术创造、抑或城市更新运动而言,都是一项令人兴奋的尝试。瑞士建筑师赫尔佐格和德·默龙在融合新与旧、城市与建筑 、身体与展品 、思想与现实等关系中,成功地把能量注入了艺术 。