摘要:
A porous sintered body composed mainly of lanthanum manganite in which a part of lanthanum atoms at A-sites of the lanthanum manganite are substituted by atoms of a metal selected from the group consisting of alkaline earth metals and rare earth metals. The dimensional shrinkage amount of the porous sintered body in heat cycling between room temperature and 1,000.degree. C. is not more than 0.01% per one heat cycle.
摘要:
A method for operating a power generator in which a solid oxide fuel cell is used as a power-generating element and an air electrode of the solid oxide fuel cell is composed of lanthanum manganite, the method involving the step of setting a heating rate and a cooling rate at least in a temperature range of 800.degree. C. to 900.degree. C. at not less than 3.degree. C./min. when the fuel cell is heated up to an operating temperature at the time of starting the power generator and when the fuel cell is cooled from the operating temperature at the time of stopping the power generator. Alternatively, the method involves the step of setting a partial pressure of oxygen, at least in a temperature range of 800.degree. C. to 900.degree. C., in an atmosphere to which the air electrode is exposed, to at not less than 10.sup.-15 arms but not more than 10.sup.-1 arms when the fuel cell is heated up to an operating temperature at the time of starting the power generator and when the fuel cell is cooled from the operating temperature at the time of stopping the power generator.
摘要:
A porous sintered body is composed of a perovskite-type composite oxide, wherein A-site of the composite oxide are occupied by one or more kinds of first metallic elements selected from the group consisting of calcium and strontium, one or more kinds of second metal elements selected from the group consisting of rare earth elements and yttrium excluding lanthanum and cerium, and lanthanum, the above one or more kinds of the first metallic elements amount to 5 to 70 mol % of the A-sites, and manganese is contained in B-sites of the composite oxide.
摘要:
There is a system for producing high-purity hydrogen by reforming a hydrocarbon and/or an oxygen atom-containing hydrocarbon to form a reformed gas containing hydrogen and separating the hydrogen from said gas. The system includes a hydrocarbon source, a water source, an oxygen source, a vaporization chamber connecting with the hydrocarbon source, the water source and the oxygen source, and a reforming chamber provided with a catalyst for steam reforming and partial oxidation and a hydrogen-separating membrane. The reforming chamber is thermally connected with the vaporization chamber. A process for producing high-purity hydrogen includes heating a reforming chamber provided with a hydrogen-separating membrane, feeding, into the reforming chamber, hydrocarbon, steam and oxygen or air to give rise to steam reforming and partial oxidation therein to produce a reaction gas, and passing the reaction gas through the hydrogen-separating membrane to recover high-purity hydrogen. The heat possessed by the portion of the reaction gas not permeable into the hydrogen-separating membrane and the heat generated by the partial oxidation are utilized for the heating and reforming of the hydrocarbon, water and oxygen or air.
摘要:
A hydrogen separator has a porous substrate having a through-hole, and a metal having a hydrogen separating ability coated on the inner surface of the through-hole of the porous substrate to close pores on the inner surface of the through-hole. A method for manufacturing a hydrogen separator by a chemical plating process, includes providing a porous substrate having a through-hole, and forcedly circulating a plating solution containing a metal having a hydrogen separating ability through the through-hole of the substrate. The inner surface of the through-hole is covered with the metal film having the hydrogen separating ability.
摘要:
A method for removing CO from a reformed gas includes the steps of treating the reformed gas by a hydrogen purifier to decrease a ratio of the concentration of components other than hydrogen to the concentration of hydrogen so that the ratio may be lower than in the reformed gas, and then converting CO contained in the gas treated by the hydrogen purifier into a gas other than CO. CO can be removed from the reformed gas, and simultaneously high-purity hydrogen can also be obtained, which leads to the increase of a fuel efficiency and the inhibition effect of performance deterioration.
摘要:
There is a system for producing high-purity hydrogen by reforming a hydrocarbon and/or an oxygen atom-containing hydrocarbon to form a reformed gas containing hydrogen and separating the hydrogen from said gas. The system includes a hydrocarbon source, a water source, an oxygen source, a vaporization chamber connecting with the hydrocarbon source, the water source and the oxygen source, and a reforming chamber provided with a catalyst for steam reforming and partial oxidation and a hydrogen-separating membrane. The reforming chamber is thermally connected with the vaporization chamber. A process for producing high-purity hydrogen includes heating a reforming chamber provided with a hydrogen-separating membrane, feeding, into the reforming chamber, hydrocarbon, steam and oxygen or air to give rise to steam reforming and partial oxidation therein to produce a reaction gas, and passing the reaction gas through the hydrogen-separating membrane to recover high-purity hydrogen. The heat possessed by the portion of the reaction gas not permeable into the hydrogen-separating membrane and the heat generated by the partial oxidation are utilized for the heating and reforming of the hydrocarbon, water and oxygen or air.
摘要:
Silicon nitride sintered bodies are disclosed, which each consist essentially of Si, O, N, and at least two kinds of rare earth elements selected from Y, Er, Tm, Yb, and Lu the bodies comprising not less than 70% by weight of Si.sub.3 N.sub.4. The ratio of the molar amount of all the rare earth elements contained in the sintered body calculated as moles of Ln.sub.2 O.sub.3, Ln being a rare earth element selected from Y, Er. Tm, Yb and Lu divided by the molar amount of oxygen calculated as moles of SiO.sub.2 is within the range of from 0.4 to 1.3. The amount of oxygen calculated as moles of SiO.sub.2 is obtained by subtracting the amount of oxygen contained in all the Ln.sub.2 O.sub.3, all the rare earth elements contained in said sintered body being considered as molecules of Ln.sub.2 O.sub.3 from the amount of oxygen contained in the sintered body and converting the remaining amount of oxygen into moles of SiO.sub.2. Any one of the rare earth elements contained in the sintered body accounts for not more than 95 mol % of all the rare earth elements contained in the sintered body. An intergranular phase of Si.sub.3 N.sub.4 grains contained in the sintered body is substantially of a crystalline phase and not less than 50% of the crystalline phase of the intergranular phase is a crystalline phases of an apatite structure. A process for manufacturing such silicon nitride sintered bodies is also disclosed.
摘要翻译:公开了氮化硅烧结体,其各自主要由Si,O,N和至少两种选自Y,Er,Tm,Yb和Lu的稀土元素组成,所述稀土元素包含不小于70重量% Si3N4。 烧结体中所含的所有稀土元素的摩尔量的比例,以Ln2O3的摩尔数计,Ln为选自Y,Er的稀土元素。 Tm,Yb和Lu除以以SiO 2摩尔计算的氧的摩尔量在0.4至1.3的范围内。 以SiO2的摩尔数计算的氧的量通过从烧结体中所含的氧的量中减去所有Ln 2 O 3中包含的所有烧结体中包含的所有烧结体中的氧被认为是Ln 2 O 3的分子而得到的氧的量, 将剩余的氧量转化为SiO 2的摩尔数。 包含在烧结体中的稀土元素中的任一种占烧结体中所含的全部稀土元素的不超过95mol%。 包含在烧结体中的Si 3 N 4晶粒的晶间相基本上是结晶相,晶间相的结晶相的50%以上是磷灰石结构的结晶相。 还公开了制造这种氮化硅烧结体的方法。
摘要:
A process is disclosed for producing silicon nitride sintered bodies. The process comprises the steps of molding a formulated starting material of silicon nitride, firing a thus obtained molding to obtain a fired body having a desired shape, and then thermally treating the fired body in such an atmosphere that has an oxygen partial pressure higher than that in a firing atmosphere and suppresses a weight increment in oxidation to not more than 0.1 mg/cm.sup.2. Working may be done to obtain the desired shape of the fired body after the firing but before the thermal treatment.
摘要翻译:公开了一种用于生产氮化硅烧结体的方法。 该方法包括以下步骤:模制配制的氮化硅原料,焙烧如此获得的模制物,以获得具有所需形状的烧制体,然后在氧分压高于其中的氧气分压的气氛中对烧成体进行热处理。 在烧成气氛中,抑制氧化重量增加至0.1mg / cm 2以下。 可以进行工作以在烧制之后但是在热处理之前获得所需的烧制体的形状。
摘要:
A process for manufacturing a silicon nitride sintered body comprises molding a mixed powder of a silicon nitride starting material and a sintering aid and firing a thus obtained molding. The firing is carried out in an N.sub.2 atmosphere or a mixed atmosphere of N.sub.2 and an inert gas to which CO.sub.2 or a mixed gas of CO.sub.2 and CO is added. Thereby, an O.sub.2 partial pressure is increased to restrain the evaporation of SiO.sub.2 and nitriding of SiO.sub.2 during the firing. The silicon nitride sintered body suffers almost no deterioration of the fired surface resulting from the evaporation of SiO.sub.2 and the nitriding of SiO.sub.2, and exhibits substantially equal four point bending strength and oxidation resistance with respect to the fired surface and the inside thereof.