Anisotropic alumina ceramics with isotropic optical properties  

作　　者：Akio IKESUE Yan Lin AUNG 

机构地区：[1]World Lab.Co.,Ltd.,Nagoya 456-8587,Japan

出　　处：《Journal of Advanced Ceramics》2023年第1期72-81,共10页先进陶瓷（英文）

摘　　要：Excellent mechanical and isotropic optical properties are achieved simultaneously from fully dense polycrystalline advanced alumina ceramics with a hexagonal crystal structure,which are optically anisotropic.A small amount(240 ppm)of ZrO_(2) additive is used to synthesize the transparent alumina ceramics with an average grain size of 0.7µm,and locally detected optical distortion(birefringence)is extremely minimized,less than 20 nm/pass.Total transmittance(86%)of the alumina ceramics(thickness=0.3 mm)in ultraviolet(UV)to infrared(IR)regions is similar to that of commercial c-axis sapphire single crystals produced by Czochralski(CZ)method,while the extinction ratio in the visible wavelength area is over 25 dB.Like glass and the c-axis sapphire single crystals,the alumina ceramics can clearly display texts and images on liquid crystal display(LCD)screens.A grain boundary phase of nano-sized Al_(2)O_(3)-ZrO_(2) composition(amorphous)is formed at the grain boundary of the advanced alumina ceramics,which enhances four-point bending strength and fracture toughness(KIC)simultaneously to 921 MPa and 6.8 MPa·m^(0.5),respectively,and hence the mechanical properties are superior to those of the sapphire single crystals.

关 键 词：ALUMINA ANISOTROPY ISOTROPY fracture toughness(KIC) optical ceramics grain boundary phase 

分 类 号：TQ174.1[化学工程—陶瓷工业]