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7 条记录 (耗时 0.025 秒)

    Preparation of substantially polycrystalline silicon carbide fibers from polyorganosiloxanes
    1.
    发明授权
    Preparation of substantially polycrystalline silicon carbide fibers from polyorganosiloxanes 失效
    从聚有机硅氧烷制备基本上多晶碳化硅纤维

    公开(公告)号：US5167881A

    公开(公告)日：1992-12-01

    申请号：US649315

    申请日：1991-01-31

    申请人： William H. Atwell ,  Duane R. Bujalski ,  Eric J. Joffre ,  Gary E. LeGrow ,  Jonathan Lipowitz ,  James A. Rabe

    发明人： William H. Atwell ,  Duane R. Bujalski ,  Eric J. Joffre ,  Gary E. LeGrow ,  Jonathan Lipowitz ,  James A. Rabe

    IPC分类号： C04B35/571

    CPC分类号： C04B35/571

    摘要： A process for the preparation of substantially polycrystalline silicon carbide fibers are provided. The fibers may be fabricated to have a small diameter and are thermally stable at high temperature. The process is carried out by initially forming fibers from a preceramic polymeric precursor comprising phenyl-containing polyorganosiloxane resins. The fibers are then infusibilized to render them nonmelting followed by a pyrolysis step in which the fibers are heated to a temperature in excess of 1600.degree. C. in a nonoxidizing atmosphere to form substantially polycrystalline silicon carbide fibers. The substantially polycrystalline silicon carbide fibers which are formed have at least 75% crystallinity and have a density of at least about 2.9 gm/cm.sup.3. The polymeric precursor or the fibers contain, or have incorporated therein, at least about 0.2 % by weight boron. This incorporation of boron may be accomplished either prior to or during formation of the fibers or during at least one of the infusibilizing or pyrolyzing steps of the process.

    摘要翻译： 提供了制备基本上多晶碳化硅纤维的方法。 纤维可以制造成具有小直径并且在高温下是热稳定的。 该方法通过初始形成来自包含含苯基的聚有机硅氧烷树脂的陶瓷前体聚合物前体的纤维进行。 然后将纤维熔融以使其不熔化，随后进行热解步骤，其中将纤维在非氧化气氛中加热至超过1600℃的温度以形成基本上多晶的碳化硅纤维。 形成的基本上多晶的碳化硅纤维具有至少75％的结晶度并且具有至少约2.9gm / cm 3的密度。 聚合物前体或纤维含有至少约0.2重量％的硼或其中并入其中。 这种硼的掺入可以在纤维形成之前或期间或在该方法的至少一个不熔化或热解步骤期间完成。

    Curable organopolysiloxanes filled with silicon carbide powders and highly densified sintered bodies therefrom
    4.
    发明授权
    Curable organopolysiloxanes filled with silicon carbide powders and highly densified sintered bodies therefrom 失效
    填充有碳化硅粉末的可固化的有机聚硅氧烷和由其高度致密化的烧结体

    公开(公告)号：US4888376A

    公开(公告)日：1989-12-19

    申请号：US248884

    申请日：1988-09-26

    申请人： William H. Atwell ,  Gary T. Burns ,  Chandan K. Saha

    发明人： William H. Atwell ,  Gary T. Burns ,  Chandan K. Saha

    IPC分类号： C04B35/571 ,  C04B35/575 ,  C08K3/34 ,  C08L83/04

    CPC分类号： C04B35/575 ,  C04B35/571

    摘要： The preparation of highly densified ceramic bodies by sintering certain curable organopolysiloxanes filled with silicon carbide powders, metal-containing sintering aids, and organopolysiloxane curing agents described. Such highly densified ceramic bodies can be prepared by either a pressure-less or a hot press sintering process. The compositions of this invention can be formed into desired shapes and then sintered to form ceramic, shaped bodies with high densities. One advantage of the present invention is that the green bodies have relative high strengths and thus can be easily handled and, if desired, machined before sintering. The curable organopolysiloxanes useful in this invention must yield a ceramic char which contains free or excess carbon in addition to carbon in the form of silicon carbide upon pyrolysis to elevated temperatures.

    Highly densified bodies from organopolysiloxanes filled with silicon carbide powders
    6.
    发明授权
    Highly densified bodies from organopolysiloxanes filled with silicon carbide powders 失效
    来自装有碳化硅粉末的有机聚硅氧烷的高致密化体

    公开(公告)号：US4929573A

    公开(公告)日：1990-05-29

    申请号：US249036

    申请日：1988-09-26

    申请人： William H. Atwell ,  Gary T. Burns ,  Chandan K. Saha

    发明人： William H. Atwell ,  Gary T. Burns ,  Chandan K. Saha

    IPC分类号： C04B35/571 ,  C04B35/575 ,  C08K3/34 ,  C08L83/04

    CPC分类号： C04B35/575 ,  C04B35/571

    摘要： The preparation of highly densified ceramic bodies by the sintering of certain organopolysiloxanes filled with silicon carbide powders, and metal-containing sintering aids is described. Such highly densified ceramic bodies can be prepared by either a pressureless sintering process or a hot press sintering process. The compositions of this invention can be formed into desired shapes and then sintered to form ceramic, shaped bodies with high densities. One advantage of the present invention is that the green bodies have relative high strengths and thus can be easily handles and, if desired, machined before sintered. The organopolysiloxanes useful in this invention must yield a ceramic char which contains free or excess carbon in addition to carbon in the form of silicon carbide upon pyrolysis to elevated temperatures.

    Mixed binder systems for agglomerates
    7.
    发明授权
    Mixed binder systems for agglomerates 失效
    用于附聚物的混合粘合剂体系

    公开(公告)号：US4659374A

    公开(公告)日：1987-04-21

    申请号：US744605

    申请日：1985-06-14

    申请人： Allan M. Alanko ,  William H. Atwell

    发明人： Allan M. Alanko ,  William H. Atwell

    IPC分类号： C22B1/244 ,  C22B5/10

    CPC分类号： C22B1/244 ,  C22B5/10

    摘要： A novel mixed binder system for agglomerates is disclosed. The agglomerates are suitable for use in the production of metals and alloys in a carbothermic reduction process such as the production of silicon in a direct arc furnace by the carbothermic reduction of silica. The agglomerates prepared using this mixture binder system have high physical strength over a wide temperature range. The mixed binder system consists essentially of a primary binder selected from the group consisting of coal tar pitch, asphalt, and petroleum pitch and a secondary binder selected from the group consisting of lignosulfonate salts, carbohydrates, and silicates.

    摘要翻译： 公开了一种用于附聚物的新型混合粘合剂体系。 附聚物适用于在碳热还原工艺中生产金属和合金，例如通过二氧化硅的碳热还原在直接电弧炉中生产硅。 使用该混合物粘合剂体系制备的附聚物在宽的温度范围内具有高的物理强度。 混合粘合剂体系基本上由选自煤焦油沥青，沥青和石油沥青的主要粘合剂和选自由木质素磺酸盐，碳水化合物和硅酸盐组成的组中的次要粘合剂组成。