Method for producing uniform, fine boron-containing ceramic powders
    42.
    发明授权
    Method for producing uniform, fine boron-containing ceramic powders 失效
    制备均匀,细微的含硼陶瓷粉末的方法

    公开(公告)号:US5194234A

    公开(公告)日:1993-03-16

    申请号:US758029

    申请日:1991-09-12

    摘要: Uniform, fine ceramic powder is prepared using an apparatus comprising (a) a cooled reactant transport member; (b) a reactor chamber; (c) a heating means; and (d) a cooling chamber. The reactant transport member comprises a wall defining a conduit that communicates with the reactor chamber, with a gas-flow space being defined along the perimeter of the transport member and in communication with the reactor chamber. The reactor chamber comprises a wall defining a reaction zone, and the heating means is associated with the reaction zone, and adapted for heating reactants in the reaction zone. The cooling chamber comprises a wall defining a cooling zone that communicates with the reactor chamber. In one embodiment the communication is by means of a cooling inlet, the diameter of the cooling zone being larger than the diameter of the cooling inlet. The temperatures of the reactant transport member, the reactor chamber, and the cooling chamber are independently controllable. Reactants can be fed through the reactant transport member into the reaction zone and reacted to form products, and the products then fed into the cooling zone to produce uniform, fine ceramic powders.

    摘要翻译: 使用包含(a)冷却的反应物输送构件的装置制备均匀的细陶瓷粉末; (b)反应室; (c)加热装置; 和(d)冷却室。 反应物输送构件包括限定与反应器室连通的管道的壁,其中气流空间沿着输送构件的周边限定并与反应器室连通。 反应器室包括限定反应区的壁,并且加热装置与反应区相关联,并且适于加热反应区中的反应物。 冷却室包括限定与反应器室连通的冷却区的壁。 在一个实施例中,通信通过冷却入口,冷却区的直径大于冷却入口的直径。 反应物输送构件,反应器室和冷却室的温度是独立可控的。 反应物可以通过反应物输送构件进料到反应区中并反应以形成产物,然后将产物进料到冷却区中以产生均匀的精细陶瓷粉末。

    Moving bed process for carbothermally synthesizing nonoxide ceramic
powders
    50.
    发明授权
    Moving bed process for carbothermally synthesizing nonoxide ceramic powders 失效
    碳热合成非氧化物陶瓷粉末的移动床工艺

    公开(公告)号:US5607297A

    公开(公告)日:1997-03-04

    申请号:US296051

    申请日:1994-08-24

    摘要: Carbothermally reduce a metal oxide to its corresponding metal nitride or metal carbide powder in a vertical gravity flow reactor by adding precursor pellets containing the metal oxide, a thermally decomposed binder material and carbon or a source of carbon directly to a heated reaction zone within the reactor. The pellets form a pellet bed, the top of which must be maintained within the heated reaction zone. The binder material is a blend of wheat and corn starches, optionally in conjunction with another binder such as melamine. The binder material thermally decomposes to a carbonaceous residue which functions both as an additional source of carbon and as a binder for the precursor pellets. The reactor may be modified by adding an internal vent line to remove volatile materials from the heated reaction zone before they have an opportunity to condense on internal reactor surfaces.

    摘要翻译: 通过将含有金属氧化物,热分解的粘合剂材料和碳或碳源的前体颗粒直接加入反应器内的加热反应区,将垂直重力流反应器中的金属氧化物碳氢化合物还原成其相应的金属氮化物或金属碳化物粉末 。 颗粒形成颗粒床,其顶部必须保持在加热的反应区内。 粘合剂材料是小麦和玉米淀粉的混合物,任选地与另一种粘合剂如三聚氰胺结合。 粘合剂材料热分解成碳素残渣,其既作为附加碳源又用作前体颗粒的粘合剂。 在反应器有机会在内部反应器表面冷凝之前,可以通过添加内部通风管线来从加热的反应区域中除去挥发性物质来改变反应器。