Alumina has now developed to be an essential part of ceramic material market, and is the most widely used fine ceramics material. It has not only the properties that traditional ceramic materials do but better and more diverse, such as high electrical insulation, high mechanical strength, high wear and chemical resistance. And high purity nano alumina can be used to manufacture single crystals and ceramics for medical, ballistic armor and transparent glass (Na-vapor glass), etc. Also, because of the special forming method alumina can be manufactured to be different work piece by different processing method, for example, 3D printing, dry pressing, hot pressing, injection molding, roll compacting, co-firing, isostatic pressing, tape casting and slip casting. [1] Alumina can be formed into many shapes, and the lower density grades with up to 10% porosity are easily cut and ground while fully dense alumina is hard and abrasion resistant which requires more specialized shaping methods. In most cases alumina was made by pressing and sintering powder, and grades ranging from 80 to 99.9% alumina. The maximum operating temperature increases with increasing alumina content.

All technical ceramics start as powders and so do alumina. The powders are mixed with a binder and molded, extruded or pressed to the desired shape. The shaped body is fired, burning off the binder and causing the powder particles to fuse together. Most grades of alumina contain a good deal of silica (up to 10%). This forms a glassy phase when heated, making the forming easier. In single crystal form alumina is sapphire, usually used for watch faces and cockpit windows of high-speed aircraft.[2]

For other abilities, there are a lot of stories to tell. Alumina has excellent hardness and strength for polishing, being substitute for industry diamond and abrasion protection, etc. And it can be used for water purification as a filter in the shape of tree roots to extent contact area. More importantly, most of the material companies value alumina as the core of high technology ceramic material, and the products of Kyocera are mainly advanced alumina material like sapphire optical windows which contain direct bond of sapphire and alumina without adhesive; electrical insulators for feedthroughs, high voltage-resistant alumina ceramic AHA100A), textile machinery parts, etc. [3]Plus,”Ortech advanced ceramics” can produce alumina with quite high proportion up to 99.8% which makes the properties more stable and strengths more powerful.[4]

References:

[1]  Ortech advanced ceramics on web, ceramics: alumina oxide ceramics Al2O3, retrieved from: https://www.ortechceramics.com/creamic-materials/alumina-ceramics/

[2] CES edupack, level2 : alumina 

[3] Best photos ceramic imagenii.Org on web,  ceramic: alumina ceramic manufacturing process , retrieved from: https://www.ortechceramics.com/creamic-materials/alumina-ceramics/

[4] Kyocera global , products ,technical data: alumina , retrieved from: https://global.kyocera.com/prdct/fc/list/material/alumina/alumina.html