Method for producing spherical silicon nitride powder

    公开(公告)号:US10384941B2

    公开(公告)日:2019-08-20

    申请号:US15839995

    申请日:2017-12-13

    Abstract: A method utilizes easily obtained carbon as carbon source for sintering, followed by high energy ball milling process with planetary ball mill for high energy homogenous mixing of the carbon source, solvent and nano-level silicon dioxide powder, along with a high energy ball milling process repeatedly performed using different sized ball mill beads, so as to formulate a spray granulation slurry with the optimal viscosity, to complete the process of micronization of carbon source evenly encapsulated by silicon dioxide powders. The optimal ratio of C/SiO2 is 1-2.5 to produce a spherical silicon dioxide powder (40-50 μm) evenly encapsulated by the carbon source. The powder is then subjected to a high temperature (1450□) sintering process under nitrogen gas. Lastly, the sintered silicon nitride powder is subjected to homogenizing carbon removal process in a rotational high temperature furnace to complete the fabricating process.

    Method for preparing spherical aluminum oxynitride powder

    公开(公告)号:US10144645B1

    公开(公告)日:2018-12-04

    申请号:US15661045

    申请日:2017-07-27

    Abstract: A method for preparing spherical aluminum oxynitride powder, comprising the steps of (A) providing an alumina powder and a resin, both of which are then dispersed and dissolved in a solvent to form a mixed slurry; (B) subjecting the mixed slurry to spray drying to form a spherical powder; (C) subjecting the spherical powder to a carbonization treatment under an inert atmosphere to form a carbonized spherical powder; (D) subjecting the carbonized spherical powder to carbothermic reduction in a nitrogen-containing atmosphere at a temperature of 1450° C. to 1550° C.; (E) keeping the spherical powder that has been subjected to carbothermic reduction in the nitrogen-containing atmosphere to carry out a nitridation reaction at a temperature of 1700° C. to 1730° C., forming a nitrided spherical aluminum oxynitride powder; (F) subjecting the nitrided spherical aluminum oxynitride powder to decarbonization in an oxygen-containing atmosphere to form the spherical aluminum oxynitride powder.

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