摘要:
A slide member has a sliding surface made of ceramic and a has surface roughness of not more than 1.0 .mu.m in center line average roughness Ra. The ceramics includes a silicon nitride sintered body which contains crystal grains having a linear density of at least 35 per 30 .mu.m in length with a boundary phase volume ratio of not more than 15 volume %, and which contains pores of not more than 20 .mu.m in maximum diameter in a content of not more than 3%. In a method of manufacturing the slide member, it is possible to ensure smoothness of the sliding surface by grinding the sliding surface and thereafter heating the ceramic in an either an inert gas or atmospheric air. A slide member that can be used under severe sliding conditions of high-speed sliding or the like and that has excellent wear resistance is obtained. Even if the slide member is used for to a sliding part of a compressor or the like which employs a fluorocarbon containing no chlorine as a cooling medium, it is possible to prevent the occurrence of seizure and abnormal wear on the sliding surface.
摘要:
A slide member has a sliding surface made of ceramic and has a surface roughness of not more than 1.0 .mu.m in center line average roughness Ra. ceramic includes a silicon nitride sintered body, which contains crystal grains having a linear density of at least 35 per 30 .mu.m in length with a boundary phase volume ratio of not more than 15 volume %, and which contains pores of not more than 20 .mu.m in maximum diameter in a content of not more than 3%. In a method of manufacturing the slide member, it is possible to ensure smoothness of the sliding surface by grinding the sliding surface and thereafter heating the ceramic in either inert gas or an atmospheric air. A slide member that can be used under severe sliding conditions of high-speed sliding or the like and that has excellent wear resistance is obtained. Even if the slide member is used for a sliding part of a compressor or the like which employs a fluorocarbon containing no chlorine as a cooling medium, it is possible to prevent the occurrence of seizure and abnormal wear on the sliding surface.
摘要:
A porous ceramic film which is formed onto and bonded to an oxide layer provided on the surface of a porous base, the film composed of finely deposited particles comprising at least one compound including (a) at least one selected from the group consisting of Si, B and Al or the group consisting of the metals of the Groups IVa, Va and VIa and (b) at least one selected from the group consisting of C and N in which the particles are intertwined with each other and bonded to each other through the component of the oxide layer to form a three-dimensionally intertwined structure. This porous ceramic film is produced by forming the oxide layer on the base surface and then heating it to a temperature of at least of the liquid-phase formation temperature of the oxide layer in a gaseous atmosphere containing the above elements (a) and (b). The porous ceramic film has a high porosity, a good pressure resistance and a regulated pore size and is appropriate for a filter, a catalyst support, bioreactor or a structural material.
摘要:
A high-porosity and high-strength porous silicon nitride body comprises columnar silicon nitride grains and an oxide bond phase containing 2 to 15 wt. %, in terms of oxide based on silicon nitride, of at least one rare earth element, and has an SiO.sub.2 /(SiO.sub.2 +rare earth element oxide) weight ratio of 0.012 to 0.65 and an average pore size of at most 3.5 .mu.m. The porous silicon nitride body is produced by compacting comprising a silicon nitride powder, 2 to 15 wt. %, in terms of oxide based on silicon nitride, of at least one rare earth element, and an organic binder while controlling the oxygen content and carbon content of said compact; and sintering said compact in an atmosphere comprising nitrogen at 1,650.degree. to 2,200.degree. C. to obtain a porous body having a three-dimensionally entangled structure made up of columnar silicon nitride grains and an oxide bond phase, and having an SiO.sub.2 /(SiO.sub.2 +rare earth element oxide) weight ratio of 0.012 to 0.65.
摘要:
A silicon nitride ceramic porous body having excellent acid and alkali resistance, mechanical strength, and durability can be employed as a filter or a catalytic carrier. The silicon nitride porous body contains a plurality of silicon nitride crystal grains with pores formed in grain boundary parts thereof, or includes a body part and a pore part wherein the body part is formed by a plurality of silicon nitride crystal grains and the pore part forms a three-dimensional network structure. The body part is formed by at least 90 vol. % of silicon nitride crystal grains, which are directly bonded to each other. In order to prepare the finished ceramic porous body, a porous body compact which is mainly composed of silicon nitride, is brought into contact with an acid and/or an alkali so that a component other than silicon nitride is partially or entirely dissolved and removed from the compact. The compact is prepared from a mixed powder of silicon nitride powder and at least one of a rare earth compound powder, a transition metal compound powder, and a bismuth compound, which is heat treated in the temperature range from 1600.degree. C. to 2100.degree. C.
摘要:
A ceramic porous body for a filter or a catalyst carrier, having a structure in which voids each having the same volume as that of a sphere of 10 .mu.m to 500 .mu.m in diameter are formed and the voids are communicated with each other through smaller fine pores, the ceramic porous body having a volume fraction of the voids and the fine pores of from 15% to 60% and being formed of components 70% or higher by volume of which is silicon nitride. The ceramic porous body is prepared by mixing coarse silicon nitride powder with fine silicon nitride powder(s) at a mixing ratio by volume of the fine silicon nitride powder to the combined volume of the fine and coarse silicon nitride powders in the range of 1/99 to 1/2; adding one or more compounds of the group IIa elements, the group IIIa elements, transition metals, Al and Si in a range of 1% to 30% by volume as their oxides to the silicon nitride powder mixture; molding the resultant powder mixture; and sintering the molded body in a non-oxidizing atmosphere of at least 0.9 atm at a temperature ranging from 1100.degree. C. to 2000.degree. C.
摘要:
A Phosphor represented by the general formula Zn(1−x)AxS:E,D is characterized by having a Blue-Cu light-emitting function. In the above general formula, A represents at least one group 2A element selected from the group consisting of Be, Mg, Ca, Sr and Ba; E represents an activator containing Cu or Ag; D represents a coactivator containing at least one element selected from group 3B and group 7B elements; and x represents a mixed crystal ratio satisfying 0≦x
摘要翻译:由通式Zn(1-x)A x S:E,D表示的荧光体的特征在于具有蓝-CU发光功能。 在上述通式中,A表示选自Be,Mg,Ca,Sr和Ba中的至少一种2A族元素; E表示含有Cu或Ag的活化剂; D表示含有选自3B族和7B族元素中的至少一种元素的共激活剂; x表示满足0 <= x <1的混晶比。 活化剂优选以等于或高于辅助激活剂的摩尔浓度包含以获得短波长的发射。 作为活化剂,分别使用Cu和Ag,而Ag可以与Au组合使用。
摘要:
A member for semiconductor devices comprising a composite alloy of aluminum or an aluminum alloy and silicon carbide, wherein silicon carbide grains are dispersed in aluminum or the aluminum alloy in an amount of from 10 to 70% by weight, the amount of nitrogen in the surface of the member is larger than that in the inside thereof, and the ratio of aluminum or the aluminum alloy to silicon carbide is the same in the surface and the inside. The member is produced by mixing powdery materials of aluminum or an aluminum alloy and silicon carbide, compacting the mixed powder, and sintering the compact in a non-oxidizing atmosphere containing nitrogen gas, at a temperature between 600.degree. C. and the melting point of aluminum. The member is lightweight and has high thermal conductivity as well as thermal expansion coefficient which is well matches with that of ceramics and others. Therefore, the member is especially favorable to high-power devices.
摘要:
A surface light-emitting device having a surface emitter for emitting visible light or ultraviolet light by electroluminescence also has multiple through-holes that define fluid channels for fluid flow in a direction orthogonal to the surface of the surface emitter. The present invention also provides an optically assisted ceramic filter composed of a ceramic filter having multiple channels, and a photocatalytic layer and surface emitter disposed on a side surface of the ceramic filter.
摘要:
The present invention provides a filter with which organic matter, bacteria, viruses, and other harmful substances can be trapped, and the trapped material can be sterilized and decomposed, at low cost and extremely high efficiency. A porous ceramic or metal is used as a substrate, and a porous semiconductor composed of a semiconductor material having a light emitting function is formed in the interior or on the surface of this substrate. An electrode is provided to this product to serve as a filter, voltage is applied so that ultraviolet light is emitted while a fluid is being filtered, and any harmful substances are filtered and simultaneously sterilized and decomposed. The porous semiconductor layer is preferably composed of columns grown perpendicular to the substrate plane, and has the function of emitting ultraviolet light with a wavelength of 400 nm or less. The pores in the porous substrate column are through-holes perpendicular to the substrate plane, and the average size of these pores is preferably from 0.1 to 100 μm. The distal ends of the columns preferably have a pointed shape. To manufacture, a suspension of semiconductor particles having a light emitting function is filtered through the porous substrate serving as a filter medium so as to form a deposited layer of semiconductor particles on the porous substrate surface. A deposited layer of p-type semiconductor particles and a deposited layer of n-type semiconductor particles may also be formed so that these form a pn junction. Further, the present invention is characterized in that an insulating layer is formed on the top and bottom surfaces of the porous semiconductor layer, and semiconductor particles are dispersed in the insulating layer, with the bandgap of the semiconductor particles in the porous light emitting layer or the porous semiconductor layer being at least 3.2 eV, and being doped with gadolinium, which is the light emitting center. In addition, the porous semiconductor layer may be made of porous silicon nitride composed of columnar Si3N4 particles with an average aspect ratio of at least 3 and an oxide-based binder phase containing at least one of rare earth element, and emit visible light or ultraviolet light.