Production method of 5N high-purity aluminum oxide polycrystal material

Abstract

The invention discloses a production method of a 5N high-purity aluminum oxide polycrystal material, which is characterized by comprising the following steps: adding a 5N high-purity aluminum oxide powder material into a cold crucible defined by a copper tube coated with a high-temperature-resistant coating, using a 5N high-purity metal aluminum sheet as an igniter, and adopting a high-frequency cold crucible technology to produce the 5N high-purity aluminum oxide polycrystal material product, wherein the appearance and shape of the product is a white columnar and acicular particle, the density is 3.5-3.9 g / cm<3>, the bulk density is 2.2-2.6 g / cm<3>, and the purity is greater than 5N. The production method disclosed by the invention is simple and easy to implement, and has the advantages of cost saving, energy saving, environment friendliness and the like.

Description

technical field [0001] The invention relates to a production method of a 5N high-purity alumina polycrystalline material, and belongs to the technical field of preparing high-purity and high-density fused alumina by a high-frequency cold crucible method. Background technique [0002] Chinese patent CN101913636A "Production method of high-purity and high-density alumina bulk raw material for sapphire single crystal", Chinese patent CN102503357A "A pre-melting crystallization method for high-purity α-alumina", Wang Jiao et al. (Preparation by cold crucible method α-Al 2 o 3 Research on process parameters of polycrystalline materials [J] Journal of Synthetic Crystals. 2012, 41 (3): 578-583). Among them, the patent CN101913636A uses graphite electrode strips as the arc-starting heating material. Although it can achieve the purpose of heating and melting, there are problems of graphite products contaminating materials and chemical reactions with raw materials at high temperatur...

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Problems solved by technology

Among them, the patent CN101913636A uses graphite electrode strips as the arc-starting heating material. Although it can achieve the purpose of heating and melting, there are problems of graphite products contaminating materials and chemical reactions with raw materials at high temperatures, which affects product quality; patent CN102503357A uses hydrogen-oxygen flame heating It is theoretically feasible to establish a melting "seed area" for alumina powder, but it is difficult to operate in practice. Specifically, when the alumina powder is heated with an oxyhydrogen flame, the powder is instantly lifted under the action of the oxyhydrogen flame flow, making it difficult to fix Heated and melted, and caused dust pollution in the operating environment; Wang Jiao et al. chose metal aluminum as the igniter, and made a study on the influence of changes in process parameters such as the form and quantity of the metal aluminum igniter, crucible drop rate, and feeding rate on product quality. After research, 4N high-density alumina polycrystalline was produced, but in the product purity test, the copper impurities were not detected and tracked. Since the high-frequency cold crucible method uses an induction coil and a cold crucible made of copper tube material, In a high-temperature environment, the surface of the copper tube is easily oxidized to form a copper compound, which is absorbed by the alumina powder raw material and brought into the crucible, resulting in a decline in product quality

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