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公开(公告)号：US4013477A
公开(公告)日：1977-03-22
申请号：US600260
申请日：1975-07-30
IPC分类号： C04B35/113 , H01M10/39 , C04B35/10
CPC分类号： H01M10/3918 , C04B35/113
摘要： A method for preparing a dense and strong polycrystalline .beta."-alumina-containing ceramic body exhibiting an elecrical resistivity at 300.degree. C of 5 ohm-cm or lower, and a controlled and uniform grain size under 50 micrometers, comprising:A. preparing fully converted .beta."-alumina seeds;B. mechanically mixing in the above-mentioned .beta."-alumina seeds with a matrix powder of a composition consistent with the formation of .beta."-alumina upon sintering; andC. sintering at about 1600.degree. C for less than 10 minutes in an open-air atmosphere or under noble metal encapsulation, a green ceramic body formed from the powder mixture of which one ingredient is the .beta."-alumina seeds and the other ingredient is the matrix powder of a composition consistent with the formation of .beta."-alumina.The polycrystalline .beta."-alumina-containing ceramic bodies obtained by the method of this invention exhibit high density, low porosity, high strength, fine grain size, and low electrical resistivity. Such polycrystalline .beta."-alumina-containing bodies are ideally suited for use as solid reaction zone separator or solid elecrolyte in certain electrical conversion devices.
摘要翻译： 一种用于制备在300℃下具有5欧姆 - 厘米或更低的电阻率和50微米以下受控且均匀的晶粒尺寸的致密且强的多晶β' - 氧化铝陶瓷体的方法，包括：
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公开(公告)号：US4138455A
公开(公告)日：1979-02-06
申请号：US787821
申请日：1977-04-15
IPC分类号： C04B35/113 , H01M10/39 , C04B35/10
CPC分类号： H01M10/3918 , C04B35/113
摘要： A method is disclosed for preparing a dense, B"-alumina-containing ceramic body exhibiting an electrical resistivity for sodium ion conduction at 300.degree. C. between about 3 and about 20 ohm-cm, by sintering a green ceramic body formed from a composition comprising at least about 90 weight percent of aluminum oxide, about 8.7 to 9.4 weight percent of sodium oxide, about 0.7-0.9 weight percent of lithium oxide, and from 0.0 to about 4.0 weight percent of magnesium oxide at a temperature between about 1400.degree. C. and about 1600.degree. C., for between about three (3) minutes and about 180 minutes to obtain a body containing both B and B"-alumina crystalline forms. The sintered body exhibits a density greater than 90% of theoretical for polycrystalline B"-alumina and a uniform grain size between about 20 and 100 micrometers. All of these compositions were prepared by using either a binary liquid forming mixture between sodium aluminate (NaAlO.sub.2) and lithium aluminate (LiAlO.sub.2), a ternary liquid forming mixture between sodium aluminate, lithium aluminate and B"-Al.sub.2 O.sub.3, or a ternary liquid forming ingredient between magnesium aluminate (MgAl.sub.2 O.sub.4), sodium aluminate and lithium aluminate, in combination with different alpha alumina powders with a range of crystallite sizes (0.3 - 5 micrometer). Depending on the state of aggregation of and the preparative technique for the liquid forming mixtures and the particle size and distribution of the alumina, resistivities (at 300.degree. C.) after sintering varied between extremes of 18-20 ohm-cm on the high side and 3-5 ohm-cm on the low side. Conditions which maximize the sintered density and minimize the resistivity for the lowest possible temperature are those preparations consisting of a fine binary or ternary liquid forming ingredient mixed with a calcined Na.sub.2 CO.sub.3 -Al.sub.2 O.sub.3 mixture. Attainment of these properties is enhanced with the use of an alpha-Al.sub.2 O.sub.3 with a wide particle size distribution (i.e., a size range of 0.3 to 6 micrometers) and an average particle size of about 5 micrometers. These low temperatures of sintering simultaneously help curtail the evaporation of soda and make an open air sintering process feasible.
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公开(公告)号：US4020134A
公开(公告)日：1977-04-26
申请号：US545046
申请日：1975-01-29
IPC分类号： C04B35/113 , C04B35/632 , C04B35/634 , C04B35/638 , H01M2/16 , H01M10/39 , C04B35/64
CPC分类号： C04B35/638 , C04B35/113 , C04B35/634 , C04B35/63444 , Y10S264/25
摘要： A method for preparing shaped, green ceramic compacts suitable for firing to form high density .beta."-alumina containing ceramic bodies comprising: (1) mixing between about 2.5 parts by weight and about 4.5 parts by weight of a ceramic composition comprising at least about 80 weight percent of aluminum oxide and from about 5 to about 15 weight percent of sodium oxide with 1 part by weight of a binder composition consisting essentially of between about 20 weight percent and about 35 weight percent of polyvinyl pyrrolidone having a number average molecular weight (M.sub.n) between about 20,000 and about 160,000 and between about 80 weight percent and about 65 weight percent of ethylene glycol; (2) extruding the mixture so formed through a die of desired configuration; and (3) heating the extrudate at temperatures and for periods of time necessary to evaporate the ethylene glycol solvent and burn off the polyvinyl pyrrolidone.
摘要翻译： 一种用于制备适于烧制以形成高密度含β-陶瓷陶瓷体的成型的绿色陶瓷压块的方法，包括：（1）将约2.5重量份至约4.5重量份的陶瓷组合物混合至包含至少约 80重量％的氧化铝和约5至约15重量％的氧化钠和1重量份的粘合剂组合物，其基本上由约20重量％至约35重量％的具有数均分子量的聚乙烯吡咯烷酮（ Mn）为约20,000至约160,000和约80重量％至约65重量％的乙二醇; （2）将所形成的混合物挤出通过所需构型的模头; 和（3）在温度和时间内加热挤出物以蒸发乙二醇溶剂所需的时间并烧掉聚乙烯吡咯烷酮。
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">4.发明授权Method of preparing dense, high strength, and electrically conductive ceramics containing .beta."-alumina 失效制备渗透性，高强度和电导电陶瓷的方法，包含“ - ”
公开(公告)号：US4113928A
公开(公告)日：1978-09-12
申请号：US788572
申请日：1977-04-18
IPC分类号： C01F7/02 , C04B35/113 , H01M10/39 , H01M6/18
CPC分类号： H01M10/3918 , C01F7/02 , C01F7/028 , C04B35/113 , C01P2004/52 , C01P2004/61 , C01P2006/10 , C01P2006/40
摘要： Methods of preparing a dense and strong polycrystalline .beta."-alumina-containing ceramic body exhibiting an electrical resistivity for sodium ion conduction at 300.degree. C of 9 ohm-cm or lower obtained directly after sintering and having a controlled fine microstructure exhibiting a uniform grain size under 50 micrometers. The invention more particularly relates to methods of uniformly distributing selected metal ions having a valence not greater than 2, e.g. lithium or magnesium, uniformly throughout the beta-type alumina composition prior to sintering to form .beta."-alumina. This uniform distribution allows more complete conversion of .beta.-alumina to .beta."-alumina during sintering. As a result, the polycrystalline .beta."-alumina containing ceramic bodies obtained by methods of this invention exhibit high density, low porosity, high strength, fine grain size (i.e. no grains over 25-50 micrometers with an average size under 5-10 micrometers), low electrical resistivity and a high resistance to degradation by water vapor in an ambient atmosphere.
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