Sintered silicon carbide ceramic body of high electrical resistivity
    3.
    发明授权
    Sintered silicon carbide ceramic body of high electrical resistivity 失效
    烧结碳化硅陶瓷体电阻率高

    公开(公告)号:US4701427A

    公开(公告)日:1987-10-20

    申请号:US789066

    申请日:1985-10-17

    摘要: Sintered silicon carbide body having a D.C. electrical resistivity of at least 10.sup.8 Ohm cm at 25.degree. C., a density of at least 2.95 g/cm.sup.3 is formed upon sintering in a nitrogenous atmosphere at a temperature of about 2250.degree. C. or greater, a shaped body composed essentially of carbon or carbon source material in amount sufficient to provide up to 2.5 percent uncombined carbon; from about 0.4 to about 2.0 percent boron carbide; up to 25 percent of temporary binder and a balance of silicon carbide which is predominantly alpha-phase. The shaped body may additionally include other sintering aids such as BN or Al without destruction of desired high electrical resistivity.

    摘要翻译: 在25℃的DC电阻率为至少108欧姆厘米的烧结碳化硅体上,在约2250℃或更高的温度下在含氮气氛中烧结时形成至少2.95克/厘米3的密度, 基本上由碳或碳源材料组成的成形体,其量足以提供高达2.5%的未组合的碳; 约0.4至约2.0%的碳化硼; 高达25%的临时粘合剂和主要是α相的碳化硅的平衡。 成形体可另外包括其它烧结助剂如BN或Al,而不破坏所需的高电阻率。

    Sintered silicon carbide/graphite/carbon composite ceramic body having
ultrafine grain microstructure
    4.
    发明授权
    Sintered silicon carbide/graphite/carbon composite ceramic body having ultrafine grain microstructure 失效
    具有超细晶粒微结构的烧结碳化硅/石墨/碳复合陶瓷体

    公开(公告)号:US4525461A

    公开(公告)日:1985-06-25

    申请号:US561361

    申请日:1983-12-14

    CPC分类号: C04B35/565

    摘要: Sintered silicon carbide/graphite/carbon composite ceramic body having a homogeneous fine grain microstructure with at least 50 percent of its silicon carbide grains having a size not exceeding about 8 microns and an aspect ratio less than about 3, with graphite grains having an average size not exceeding that of the silicon carbide grains microns uniformly dispersed throughout the matrix of silicon carbide and having a density of at least 75 percent of theoretical can be made by firing of a shaped green body having a density of at least about 45 percent of theoretical, the shaped green body containing graphite of fine particle size, a sintering aid selected from the group consisting of aluminum, beryllium or boron or compounds containing any one or more of these or a mixture of any of the foregoing elements or compounds, silicon carbide having a surface area of from about 5 to about 100 square meters/gram and, optionally, a temporary binder at a sintering temperature of from about 1900.degree. C. to about 2300.degree. C. in an inert atmosphere or vacuum. The process for making such pressureless-sintered composite bodies is relatively undemanding of exact temperature/time control during sintering. Contain embodiments of such composite sintered bodies may electrical-discharge machined.

    摘要翻译: 烧结碳化硅/石墨/碳复合陶瓷体具有均匀的细晶粒微结构,其碳化硅晶粒的至少50%具有不超过约8微米的尺寸,纵横比小于约3,石墨晶粒具有平均尺寸 不超过碳化硅颗粒均匀分散在整个碳化硅基体中并且具有至少理论值的75%的密度的碳化硅颗粒可以通过烧结具有至少约理论值的约45%的成形生坯, 包含细颗粒尺寸的石墨的成形生坯,选自铝,铍或硼的烧结助剂或含有这些或任何上述元素或化合物的任何一种或多种的化合物的化合物,具有 表面积为约5至约100平方米/克,并且任选地为约190℃的烧结温度的临时粘合剂 0℃至约2300℃。 制造这种无压烧结复合体的方法在烧结期间精确的温度/时间控制相对不高。 包含这种复合烧结体的实施例可以进行放电加工。

    Silicon carbide bodies having high toughness and fracture resistance and
method of making same
    5.
    发明授权
    Silicon carbide bodies having high toughness and fracture resistance and method of making same 失效
    具有高韧性和耐断裂性的碳化硅体及其制造方法

    公开(公告)号:US5298470A

    公开(公告)日:1994-03-29

    申请号:US960178

    申请日:1992-10-09

    CPC分类号: C04B35/565 C04B35/575

    摘要: A sintered silicon carbide ceramic body preferably produced from a uniform mixture comprising from about 82 percent to about 99.4 percent by weight silicon carbide, from about 0.5 percent to about 10 percent by weight of a nitrogen containing aluminum compound and from about 0.1 to about 8 percent of a rare earth oxide, both reacted with oxygen, wherein said sintered ceramic body has a density greater than 90% percent of theoretical and a fracture toughness, as measured by a single edge notched beam test, of more than 7 MPam.sup.1/2 and method of making the same.

    摘要翻译: 优选由均匀混合物制备的烧结碳化硅陶瓷体,其包含约82重量%至约99.4重量%的碳化硅,约0.5重量%至约10重量%的含氮化合物和约0.1至约8重量% 的稀土氧化物都与氧反应,其中所述烧结陶瓷体的密度大于理论值的90%,通过单边缘切割梁试验测得的断裂韧性大于7Mamam 1/2,和方法 做同样的事情

    Hexagonal silicon carbide platelets and preforms and methods for making
and using same
    6.
    发明授权
    Hexagonal silicon carbide platelets and preforms and methods for making and using same 失效
    六角形碳化硅片和预型件及其制造和使用方法

    公开(公告)号:US5002905A

    公开(公告)日:1991-03-26

    申请号:US184994

    申请日:1988-04-22

    IPC分类号: C01B31/36 C04B35/80 C30B25/00

    摘要: Crystalline silicon carbide wherein at least 90 weight percent of the silicon carbide is formed from a plurality of hexagonal crystal lattices wherein at least 80 weight percent of the crystals formed from the lattices contain at least a portion of opposing parallel base faces separated by a distance of from 0.5 to 20 microns. The crystals may be in the form of separate particles, e.g. separate platelets, or may comprise an intergrown structure. The crystalline silicon carbide of the invention is produced by heating a porous alpha silicon carbide precursor composition comprising silicon and carbon in intimate contact to a temperature of from 2100.degree. C. to 2500.degree. C. in a non-reactive atmosphere. The materials are high performance materials finding use in reinforcing, high temperature thermal insulating, improvement of thermal shock resistance, and modification of electrical properties.

    摘要翻译: 结晶碳化硅,其中至少90重量%的碳化硅由多个六角晶格形成,其中至少80重量%的由晶格形成的晶体包含至少一部分相对的平行基面, 0.5至20微米。 晶体可以是分开的颗粒的形式,例如, 单独的血小板,或可以包括共生的结构。 本发明的结晶碳化硅通过在非反应性气氛中加热包含硅和碳的多孔α碳化硅前体组合物在2100℃至2500℃的温度下紧密接触来制备。 这些材料是用于增强,高温绝热,提高耐热冲击性和改善电性能的高性能材料。

    Single phase silicon carbide refractory
    8.
    发明授权
    Single phase silicon carbide refractory 失效
    单相碳化硅耐火材料

    公开(公告)号:US4693988A

    公开(公告)日:1987-09-15

    申请号:US880708

    申请日:1986-07-01

    IPC分类号: C04B35/565 C04B35/56

    CPC分类号: C04B35/565

    摘要: The present invention provides a method of pressureless sintering silicon carbide in which the silicon carbide starting material is in the form of a multimodal composition, or mixture, of coarse and submicron particles. The present sinterable silicon carbide mixtures consist of separate fractions of sized particles. Each fraction is present in amounts of from about 5 to about 75% by weight of the mixture, and more preferably from about 10 to about 65% by weight of the mixture. One fraction has a particle size ranging between about 0.21 mm (210 microns) to about 3.4 mm (3400 microns) and preferably the larger particles have a size less than about 2.4 mm. A second fraction has a particle size ranging between about 0.003 mm (3 microns) up to about 0.21 mm. A third fraction has a size less than 0.003 mm, but has an average size less than 1 micron. The present products are produced by sintering particulate silicon carbide in the presence of a sintering aid and a slight excess carbon. Generally, sintering temperatures range from about 1900.degree. C. to about 2300.degree. C. depending upon the sintering atmosphere.

    摘要翻译: 本发明提供了一种无压烧结碳化硅的方法,其中碳化硅原料是多峰组合物或混合物形式的粗亚微米颗粒。 本发明的可烧结碳化硅混合物由大小分散的颗粒组成。 每个级分的存在量为混合物的约5至约75重量%,更优选为混合物重量的约10至约65重量%。 一个部分具有在约0.21mm(210微米)至约3.4mm(3400微米)之间的粒度,优选较大的颗粒具有小于约2.4mm的尺寸。 第二部分具有在约0.003mm(3微米)至约0.21mm之间的粒度范围。 第三部分具有小于0.003mm的尺寸,但平均尺寸小于1微米。 本产品通过在烧结助剂和少量过量碳存在下烧结颗粒状碳化硅来制备。 通常,烧结温度范围为约1900℃至约2300℃,这取决于烧结气氛。

    Inert autogenous attrition grinding
    10.
    发明授权
    Inert autogenous attrition grinding 失效
    惰性自体磨耗研磨

    公开(公告)号:US4932166A

    公开(公告)日:1990-06-12

    申请号:US252751

    申请日:1988-10-03

    摘要: A method for grinding an oxygen sensitive ceramic material to a powder which comprises grinding an oxygen sensitive ceramic feed material having an average particle size of between 1 and 200 microns in a contamination free high energy autogenous attrition mill in non-oxidizing fluid in the presence of media for a sufficient time to obtain a specific surface area of at least 5 m.sup.2 /g and preferably at least 9 m.sup.2 /g. The media consists essentially of the same ceramic as the feed material is of high purity and has an average particle size of less than 4 mm and preferably less than 2.5 mm. the ground material may be further treated so that the average particle size is less than one micron and so that the greater than 97 numerical percent of the particles of the finished powder is smaller than 5 microns. The invention includes the finished powder.

    摘要翻译: 一种将氧敏感性陶瓷材料研磨成粉末的方法,该方法包括在非氧化性流体中的无污染的高能自生磨碎机中研磨平均粒度为1至200微米的氧敏感陶瓷进料, 培养基足够的时间以获得至少5m 2 / g,优选至少9m 2 / g的比表面积。 介质基本上由与原料高纯度相同的陶瓷组成,平均粒度小于4毫米,最好小于2.5毫米。 可以进一步处理研磨材料,使得平均粒度小于1微米,使成品粉末的颗粒的大于97数值百分比小于5微米。 本发明包括成品粉末。