Preparation And Properties Of Al₂O₃/MgAl₂O₄ Infrared Transparent Ceramics

Transparent alumina ceramics which has the advantages of short production cycle, easy preparation condition to single crystal material and has better mechanical properities to glass material, The research and application of it is relatively early. Anymore Transperent alumina ceramics has good thermal conductivity and thermal stability, high temperature strength and greater corrosion resistance, and it is widely used in lighting, high temperature insulation, and so on. In addition, it also has a certain development in the laser and the military.In order to improve transmittance of ceramic, we choiced sheet magnesia-alumina spinel as template and joined alumina powder, then applied tape casting in order to improve the template orientation rate and made ceramics textured to reduce the impact of crastyle boundary reflection and birefringence on transmission. Meantime as contrast, we prepared ceramic with the same template on means of compression molding and isostatic pressing. Then phase and morphology test analysis was done to prepared ceramic.This paper used the 100nm in diameter sphericalα-Al₂O₃ which was prepared by pyrolysis precursor body as raw material, and applied 10μm in diameter hexagonal flakes MgAl₂O₄ which was prepared by molten salt law as template. Then porcelain body was prepared whose tempale content is 2wt%, 5wt% and 10wt% by casting method, molding method and static pressure method, meanwhile used porcelain body without template as contrast. This paper prepared transparent ceramic under vacuum at 1800℃about 15h whose infrared transmission rate up to 60%, higher than ceramic by static pressure method and molding method, and as contrast to the ceramic without template the infrared transmission rate increased by 2 times.Ceramic prepared by casting method has some preferred orientation, and with the increase of template content, the degree of orientation gradually increase, when the template content up to 10wt%, the degree of orientation is highest to 0.40. Template also has largely inhibited the abnormal grain growth and improves the density of the ceramics, and makes fracture mode of ceramic into the combination of intergranular fracture and transgranular fracture to improve the hardness of the ceramic.