摘要:
A gas-tight article includes a sintered body composed mainly of a silicon carbide, and a film of silicon carbide formed on a surface of the sintered body by chemical vapor deposition and covering said surface of the sintered body, wherein cracks are formed in the film of the silicon carbide, and the cracks are filled with metallic silicon.
摘要:
A corrosion-resistant member includes a substrate made of a ceramic material and having a diameter of at least 200 mm, and a film of chemically vapor deposited silicon carbide having a thickness of not less than 0.5 mm and covering at least such a portion of the surface of the substrate that is to contact a corrosive material. A process is disclosed for producing such a corrosion-resistant member, which process includes thermally treating the film at a temperature higher, by not less than 50.degree. C. centigrade, than a film-forming temperature at which the film of silicon carbide is formed, after the formation of the silicon carbide film.
摘要:
A corrosion-resistant member includes a substrate made of a ceramic material and having a diameter of at least 200 mm, and a film of chemically vapor deposited silicon carbide having a thickness of not less than 0.5 mm and covering at least such a portion of the surface of the substrate that is to contact a corrosive material. A process is disclosed for producing such a corrosion-resistant member, which process includes thermally treating the film at a temperature higher, by not less than 50° C. centigrade, than a film-forming temperature at which the film of silicon carbide is formed, after the formation of the silicon carbide film.
摘要:
A first inorganic powder molded body and a second inorganic powder molded body are obtained. Each of the bodies contains an inorganic powder, an organic dispersion medium having a reactive functional group and a gelling agent and is solidified by chemical reaction of the organic dispersion medium and the gelling agent. Slurry containing a powder component and an organic dispersion medium is applied to a joint surface of the first inorganic powder molded body. The inorganic powder molded bodies are allowed to abut on each other while interposing the slurry therebetween, and integrated together into a joined body. A sintered body is obtained by sintering the joined body.
摘要:
An arc tube includes a light emitting body for light therein and a ceramic tube having a first capillary and a second capillary integral with respective opposite sides of the light emitting body. A first electrode is inserted and sealed in the first capillary, and a second electrode is inserted and sealed in the second capillary. The first electrode is sealed in the first capillary by shrink fitting.
摘要:
A mold includes a gate communicating with the entire perimeter of a cavity serving as a space configured to form a molded article. A self-curable molding material with flowability is fed into the perimeter of the cavity through the gate; hence, the mold has a small number of dead ends compared with the case where, for example, the molding material is fed into the cavity through a part of the cavity, preventing the formation of bubbles left in the cavity. The arrangement of a gate and a vent each making an acute angle results in the spontaneous separation of the molded article in the cavity from solidified material portions in the gate and the vent due to shrinkage on curing.
摘要:
A mold includes a gate communicating with the entire perimeter of a cavity serving as a space configured to form a molded article. A self-curable molding material with flowability is fed into the perimeter of the cavity through the gate; hence, the mold has a small number of dead ends compared with the case where, for example, the molding material is fed into the cavity through a part of the cavity, preventing the formation of bubbles left in the cavity. The arrangement of a gate and a bent each making an acute angle results in the spontaneous separation of the molded article in the cavity from solidified material portions in the gate and the vent due to shrinkage on curing.
摘要:
A silicon nitride ceramic of the present invention possesses excellent strength of the surface, including a silicon nitride and a rare earth oxide compound and being characterized in that the ratio of the transverse rupture strength, at a room temperature, of the fired surface used as a tensile surface to the transverse rupture strength, at a room temperature, of the worked surface used as a tensile surface subjected to the working so as to have the surface roughness of R.sub.MAX 0.8 .mu.m or less is 0.7 or more, and the strength ratio is satisfied even when any portion besides the fired surface is utilized as the tensile surface to be worked to have the surface roughness of R.sub.MAX 0.8 .mu.m or less. The present invention also provides a process for producing a silicon nitride ceramic including the steps of: (1) mixing .alpha.-Si.sub.3 N.sub.4 powder and .beta.-Si.sub.3 N.sub.4 powder to obtain a raw material powder so as to satisfy the formula indicated by 0.05.ltoreq..beta./.alpha.+.beta..ltoreq.0.50, in which a refers to the weight of .alpha.-Si.sub.3 N.sub.4 powder and .beta. refers to the weight of .beta.-Si.sub.3 N.sub.4 powder; (2) mixing at least one sintering aid to the raw material powder; (3) forming the powder mixture to give a compact; and (4) firing the compact at a temperature ranging from 1800.degree. to 2000.degree. C. under a nitrogen atmosphere having an atmospheric pressure of at least 1 atm.
摘要翻译:本发明的氮化硅陶瓷具有优异的表面强度,包括氮化硅和稀土氧化物,其特征在于,在室温下,作为烧结表面的烧结表面的横向断裂强度的比例 作为经受加工的拉伸面的加工面的拉伸面与横向断裂强度在室温下的表面粗糙度为0.8μm以下,强度比为 即使将烧成的表面以外的任何部分用作待加工的拉伸面,其表面粗糙度为0.8μm以下。 本发明还提供一种制造氮化硅陶瓷的方法,包括以下步骤:(1)将α-Si 3 N 4粉末和β-Si 3 N 4粉末混合以获得原料粉末,以满足0.05≤β /α+β<0.50,其中a表示α-Si 3 N 4粉末的重量,β表示β-Si 3 N 4粉末的重量; (2)将至少一种烧结助剂与原料粉末混合; (3)形成粉末混合物以产生致密的; 和(4)在大气压至少为1个大气压的氮气气氛下,在1800〜2000℃的温度下烧成。
摘要:
A ceramic blade for a hybrid type gas turbine blade has a dovetail portion, a platform portion formed on the dovetail portion and blade portions formed on the platform portion. The number of the blade portions formed on one platform portion is two or more. The upper surface of the platform portion is shaped into an arc-like form, and the dovetail portion is linearly formed in a tangential direction to a turbine rotation direction. By the utilization of this blade, the hybrid type gas turbine blade can inhibit the leakage of a gas and can be easily manufactured and is excellent in durability.
摘要:
A novel solid solution has a composition of R.sub.y Zr.sub.4 Si.sub.x P.sub.6-x O.sub.24 (R is at least one forming bivalent or trivalent element 0.ltoreq.x.ltoreq.2, 2/3.ltoreq.y.ltoreq.2). Furthermore, a heat-resistant sintered body and heat-resistant phosphate based compound sintered body comprises the above solid solution and has excellent heat resistance and high temperature stability. And also, a method of producing such sintered bodies is disclosed.