On the material properties put forward higher requirements, forcing the research and development of materials to a deeper and more extensive expansion direction

As we all know , energy, materials and information are the three pillar industries of China's modernization , the material is vanguard , and its development is often the precursor of major grinding wheel change and signs , while the modern requirements of the development of new materials and gave a strong impetus. In recent years, such as electronics, heat , laser, aerospace technology, automatic control , energy and information processing , and many other areas of the rapid development of emerging technologies , the performance of the material put polycrystalline diamond requirements , forcing the research and development of materials to a deeper and more broad direction of expansion. As a new special ceramics , inorganic non-metallic materials , with its unique fine structure and multi-effect , a variety of performance rapidly and widely applied in materials  synthetic diamond  of vast areas stand out, to bring the ancient ceramics new vitality. This is because the melting point and hardness of the ceramic material than metal materials generally high, with also has good insulating properties and chemical stability ( especially resistance to corrosion , oxidation resistance ) , so that it is in many high technology applications in the field increasingly extensive. Wherein the oxide ceramic high temperature oxidation due superior performance, making it easier , cheaper , it is a large number of application areas and industrial production of a high-temperature materials . 2 Literature Review Alumina is an amphoteric compounds, ionic bonding , the Department of hexagonal crystals.