摘要:
A silicon nitride composite sintered which comprises crystal grains of silicon nitride and/or sialon having an average minor axis length of 0.05 to 3 .mu.m and an aspect ratio of 10 or less and foreign particles dispersed in the crystal grains and/or the grain boundary phase, said particles having a thermal expansion coefficient of 5.times.10.sup.-6 /.degree.C. or more and an average particle size of 1 to 500 nm. The sintered body is produced by wet mixing silicon nitride powder, at least two sintering aids selected from among Y.sub.2 O.sub.3, Al.sub.2 O.sub.3, AlN and MgO and at least one compound selected from among the oxides, nitrides, carbides and silicides of the elements, excluding Si and C, of the groups IIa, IIIa, IVa, Va, VIa, IIb, IIIb and IVb of the Periodic Table to form a molding; and heat treating under the specified conditions. The sintered body can also be obtained by coating the surfaces of silicon nitride crystal grains with an organometallic compound convertible to the above foreign particles, heat treating and sintering with the sintering aid.
摘要翻译:一种氮化硅复合材料,其包含平均短轴长度为0.05〜3μm,长径比为10以下的氮化硅和/或赛隆的晶粒和分散在晶粒和/或晶界中的异物的氮化硅复合体 所述颗粒的热膨胀系数为5×10 -6 /℃以上,平均粒径为1〜500nm。 烧结体通过湿式混合氮化硅粉末,至少两种选自Y 2 O 3,Al 2 O 3,AlN和MgO的烧结助剂和选自元素的氧化物,氮化物,碳化物和硅化物中的至少一种化合物,除Si和 C,元素周期表IIa,IIIa,IVa,Va,VIa,IIb,IIIb和IVb族中的一种,形成一个成型体; 并在规定条件下进行热处理。 烧结体也可以通过用可转化为上述外来颗粒的有机金属化合物涂覆氮化硅晶粒表面,用烧结助剂进行热处理和烧结来获得。
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 composite bearing structure can withstand high speed rotation has first, second and third bearing components. The first bearing component supports a radial impact force applied to a rotator during rotation, and is made of an inner ring (1) and an outer ring (2) of silicon nitride ceramic sintered bodies. The second bearing component supports an axial load applied to the rotator while maintaining a required clearance between itself and the rotator and is made of two permanent magnets (12, 13) positioned thrustdirectionally opposite to each other. The third bearing component maintains a radial rotational accuracy of the rotator, and is made of a radial dynamic pressure producing groove (5) provided on a cylindrical surface of the inner ring (1).
摘要:
A composite bearing structure that has a high rotational accuracy and that can withstand high-speed rotation comprises first bearing means, second bearing means, third bearing means and fourth bearing means. The first bearing means supports a radial impact force which is applied to a rotator during rotation, and is formed by an inner ring (1) and an outer ring (2) consisting of silicon nitride ceramics sintered bodies. The second bearing means supports an axial load which is applied to the rotator while maintaining a prescribed clearance with the rotator, and is formed by a magnetic bearing body of two permanent magnets (12) and (13) which are thrust-directionally opposed to each other. The third bearing means maintains the radial rotational accuracy of the rotator, and is formed by a radial dynamic pressure producing groove (5) which is formed in a cylindrical surface of the inner ring (1). The fourth bearing means maintains the thrust-directional rotational accuracy of the rotator, and is formed by an air dome portion (100) which is confined in a semi-closed state by the inner ring (1), the outer ring (2) and a cover (4).
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:
An SiC whisker-reinforced Si.sub.3 N.sub.4 composite material comprising a sintered body of an Si.sub.3 N.sub.4 matrix having dispersed therein SiC whiskers, wherein said SiC whiskers are uniaxially orientated; a process for producing an SiC whisker-reinforced Si.sub.3 N.sub.4 composite material which comprises mixing (1) SiC whiskers having a coating comprising an oxide of at least one metallic element selected from the group consisting of Be, Mg, Ca, Sr, and Ba of the group 2A; Sc, Y, and La of the group 3A; Ti, Zr, and Hf of the group 4A; and Li, Al, and Si with (2) Si.sub.3 N.sub.4 powder, and sintering the mixture; and a process for forming said metal oxide coating on the surface of whiskers which comprises dipping whiskers in a solution of an inorganic or organic salt of at least one metallic element selected from the group consisting of the elements of the groups 2A, 3A, and 4A of the periodic table, Li, and Al and heat treating the whiskers having adhered thereto the metallic salt at a temperature not less than the thermal decomposition temperature of said metallic salt. The SiC whisker-reinforced Si.sub. 3 N.sub.4 composite material exhibits improved strength particularly at high temperatures and improved toughness.
摘要:
A method of producing a silicon nitride ceramic component, comprising: grinding a silicon nitride sintered body comprising .alpha.--Si.sub.3 N.sub.4 having an average grain size of 0.5 .mu.m or smaller and .beta.'-sialon having an average grain size of 3 .mu.m or smaller in major axis and 1 .mu.m or smaller in minor axis into a predetermined size with a surface roughness of 1-7 .mu.m in ten-point mean roughness; heat treating the same at temperature range of 800.degree.-1200.degree. C. in the air; and standing it to allow to be cooled, whereby providing a residual stress in the ground surface before and after the heat treating as a residual compressive stress at a ratio of 1 or higher of the residual compressive stress after the heat treating to that before the heat treating (residual compressive stress after the heat treating/residual compressive stress before the heat treating), preferably 5 or more.
摘要翻译:一种氮化硅陶瓷成分的制造方法,其特征在于,包括:研磨包含平均粒径为0.5μm以下的α-Si 3 N 4,平均粒径为3μm以下的β'赛隆的氮化硅烧结体 长轴和1μm或更小的短轴成预定尺寸,十点平均粗糙度的表面粗糙度为1-7μm; 在空气中在800〜1200℃的温度范围进行热处理; 并将其放置以允许冷却,由此在热处理之前和之后的地面中提供作为残余压应力的残余应力在热处理后的剩余压缩应力为1或更高的比例 处理(热处理后的残余压应力/热处理前的残余压应力)优选为5以上。
摘要:
The present invention relates to a method of sintering ceramics and ceramics obtained by said method. According to the present invention, the synthesis and sintering of ceramics can be simultaneously carried out by utilizing the reaction heat generated when at least one metallic element selected from metallic elements of IIIb, IVa, Vb and VIb groups of the Periodic Table is combined with at least one nonmetallic element such as B, C, N and Si without heat or by preliminarily heating the ceramics at temperatures remarkably lower than the usual sintering temperature ceramics, thus-produced are superior in abrasion resistance and corrosion resistance. Furthermore, according to the present invention, particles of the same kind of metal as that used in constructing the ceramics comprising the above described metallic elements and nonmetallic elements are dispersed in a matrix comprising said ceramics to obtain metal dispersed reinforced ceramics in which both the matrix and the metallic particles are strongly and chemically bonded to each other. According to the latter procedure ceramic materials having high temperature characteristics, high corrosion resistance and high abrasion resistance, as well as high toughness and high impact resistance can be obtained.
摘要:
Disclosed herein are a method for molding a high density and homogeneous silicon nitride ceramics within a short time and an apparatus used for the method. A gel-like slurry mixture which is a mixture of ceramic powders consisting mainly of Si.sub.3 N.sub.4 and a liquid and has a powder content of from 45 vol % to 60 vol % is fluidized by imparting thereto a strain by vibration, and the mixture under the fluidized state is filled into, and molded by, a mold. Preferably, the entire part or a part of the mold is made of a liquid permeable material. The vibration preferably has an acceleration of from 0.1 G to 150 G and an amplitude of 1 .mu.m to 1 cm. Furthermore, the viscosity of the slurry filled into the mold is preferably from 2,000 to 20,000 cps.
摘要翻译:本文公开了一种用于在短时间内模制高密度均匀氮化硅陶瓷的方法和用于该方法的装置。 作为主要由Si 3 N 4和液体组成的粉末含量为45体积%至60体积%的陶瓷粉末的混合物的凝胶状浆料混合物通过振动赋予其应变而流化,并且流化床 状态被模具填充并模制。 优选地,模具的整个部分或一部分由液体可渗透的材料制成。 振动优选具有0.1G至150G的加速度和1μm至1cm的振幅。 此外,填充到模具中的浆料的粘度优选为2,000至20,000cps。
摘要:
The present invention relates to a method of sintering ceramics and ceramics obtained by said method. According to the present invention, the synthesis and sintering of ceramics can be simultaneously carried out by utilizing the reaction heat generated when at least one metallic element selected from metallic elements of IIb, IVb, Vb and VIb groups of the Periodic Table is combined with at least one nonmetallic element such as B, C N and Si without heat or by preliminarily heating the ceramics at temperatures remarkably lower than the usual sintering temperature ceramics thus-produced are superior in abrasion resistance and corrosion resistance. Furthermore, according to the present invention, particles of the same kind of metal as that used in constructing the ceramics comprising the above described metallic elements and nonmetallic elements are dispersed in a matric comprising said ceramics to obtain metal dispersed reinforced ceramics in which both the matrix and the metallic particles are strongly and chemically bonded to each other. According to the latter procedure, ceramic materials having high temperature characteristics, high corrosion resistance and high abrasion resistance, as well as high toughness and high impact resistance can be obtained.