摘要:
A process for producing high density sintered product which comprises molding a composite of an inorganic powder and an organic resin, burning off the organic resin, coating the surface of the molding with a rubber film, pressing said moldings under 2 ton/cm.sup.2 or more of isostatic pressure, and sintering.
摘要:
Processes for the production of a silicon nitride sintered body are disclosed. One process comprises molding a mixed powder of 100 parts by weight of metallic silicon with a maximum particle size of 20 .mu.m or less and 0.2 to 2 parts by weight (calculated as chromium oxide) of a chromium component and, thereafter, reaction sintering the mold in a nitrogen gas or in a non-oxidizing atmosphere containing nitrogen gas at a temperature of 1,300.degree. to 1,500.degree. C. This invention provides further process which comprises molding a mixed powder of 100 parts by weight of metallic silicon with a maximum particle size of 20 .mu.m or less, 0.2 to 1 part by weight (calculated as chromium oxide) of a chromium component, and further 10 to 20 parts by weight of an oxide component of one or more of the oxides of yttrium, lanthanum, cerium, gadolinium, and erbium, reaction sintering the above-prepared mold, and thereafter, hot pressing the reaction sintered body. This silicon nitride hot pressed body is superior in oxidation resistance, and moreover is of high density and has high mechanical strength. Thus it is suitable for use as, e.g., gas turbine parts of diesel engine parts.
摘要:
A silicon nitride sintered product and processes for the production thereof are described, wherein the product comprises from 75 to 97.9% by weight of silicon nitride, from 2 to 20% by weight of yttrium oxide and cerium oxide in a molar ratio of cerium oxide to yttrium oxide of 0.4/1 to 4/1, and from 0.1 to 8% by weight of aluminum oxide.
摘要:
A process for producing a silicon nitride sintered product having high toughness is described, comprising blending from 97 to 57% by weight of metallic silicon powder having a maximum particle size of 25 .mu.m or less with from 1 to 15% by weight, calculated as TiN, of a TiN powder having a maximum particle size of 20 .mu.m or less or a powder of titanium component capable of changing into TiN during reaction sintering, and from 2 to 28% by weight of one or more components selected from the group consisting of AlN, Al.sub.2 O.sub.3, SiO.sub.2 and oxides of rare earth elements, molding the resulting mixture, carrying out reaction sintering in a nonoxidizing atmosphere of a nitrogen gas or a nitrogen-containing mixed gas, and thereafter resintering in the same atmosphere at a temperature of from 1,600.degree. C. to 2,200.degree. C.
摘要:
A silicon nitride based ceramic tool is disclosed which is prepared from the starting powder compositions surrounded by and including the lines defined by the points A, B, and C and preferably D, E, and F in the FIGURE.
摘要:
A high strength silicon nitride sintered material having a modulus of rupture of about 100 kg/mm.sup.2 or more, which is prepared by sintering a mixture of about 88.7 to 98% by weight of silicon nitride (Si.sub.3 N.sub.4) and the balance a sintering aid comprising Al.sub.2 O.sub.3, Y.sub.2 O.sub.3 and Ti present in the following proportions based on weight: ##EQU1##
摘要翻译:通过烧结约88.7-98重量%的氮化硅(Si 3 N 4)的混合物制备的具有约100kg / mm 2或更高的断裂模量的高强度氮化硅烧结材料,其余为包含Al 2 O 3的烧结助剂 ,Y 2 O 3和Ti以以下重量比例存在:
摘要:
A sintered silicon nitride products and processes for the fabrication thereof are described, wherein the product comprises from 60 to 98.9% by weight of silicon nitride, from 0.1 to 15% by weight of one or more chromium components selected from metal chromium, chromium oxide, and chromium nitride, and from 1 to 25% by weight of one or more oxides selected from oxides of rare earth elements, scandium oxide, yttrium oxide, aluminum oxide, zirconium oxide and silicon dioxide.
摘要:
A high toughness sintered body is described, consisting essentially of from 40 to 99.5% by weight of Component A, and 0.5 to 60% by weight of Component B, wherein the mean grain size of the sintered body is 3 microns or less, and Components A and B are as follows:Component A: ZrO.sub.2 containing a stabilizer, such as Y.sub.2 O.sub.3, CaO, and MgO, in which the fraction of the tetragonal and cubic ZrO.sub.2 constitutes at least 90% by weight, and the ratio of the tetragonal ZrO.sub.2 to the cubic ZrO.sub.2 is at least 1/3; andComponent B: at least one of Al.sub.2 O.sub.3 and TiN, with impurities being 3% by weight or less of SiO.sub.2, 0.5% by weight or less of Fe.sub.2 O.sub.3, and 0.5% by weight or less of TiO.sub.2, provided that the total amount is 3% by weight or less.
摘要翻译:描述了高韧性烧结体,其基本上由组分A的40至99.5重量%和组分B的0.5至60重量%组成,其中烧结体的平均晶粒尺寸为3微米或更小,并且组分 A和B如下:组分A:含有稳定剂如ZrO 2,CaO和MgO的ZrO 2,其中四方晶和立方ZrO 2的分数占至少90重量%,四方晶ZrO 2与 立方ZrO 2至少为1/3; 和组分B:Al 2 O 3和TiN中的至少一种,杂质为3重量%以下的SiO 2,0.5重量%以下的Fe 2 O 3和0.5重量%以下的TiO 2,前提条件是总量为3 重量%以下。
摘要:
A process for producing silicon carbide heating elements is described comprising:a primary sintering wherein a mixture including SiC powder, boron or a boron compound, and carbon or a carbon compound in specific proportions, is molded and sintered to obtain a sintered product having from 70 to 95% of the theoretical density; anda secondary sintering wherein the sintered product obtained in the primary sintering is further sintered at each temperature from 1,600.degree. C. to 2,200.degree. C. to obtain a sintered product having a density of at least 80% of the theoretical density and a specific resistivity of not more than 1.0 .OMEGA.-cm.
摘要:
A method for manufacture of a high toughness sintered body, characterized by sintering a shaped body of a mixed powder consisting essentially of from 40 to 70% by weight of a first component of powdered ZrO.sub.2 containing at least one stabilizer selected from the group consisting of Y.sub.2 O.sub.3, CaO, and MgO and having an average particle diameter of not more than 1.mu. and from 30 to 60% by weight of a second component of powdered .alpha.-Al.sub.2 O.sub.3 having an average particle diameter of not more than 1 .mu.m, which mixed powder may also contain not more than 3% by weight of SiO.sub.2, not more than 0.5% by weight of Fe.sub.2 O.sub.3, or not more than 0.5% by weight of TiO.sub.2 in a combined proportion of not more than 3% by weight at a temperature in the range of from 1400.degree. C. to 1600.degree. C. under normal pressure thereby producing a sintered body wherein at least 90% by weight of ZrO.sub.2 particles present therein are accounted for by tetragonal and cubic crystals, the ratio of said tetragonal crystals to said cubic crystals is at least 1:3, and the average crystal particle diameter of the entire sintered body is at least 3.mu..
摘要翻译:一种制造高韧性烧结体的方法,其特征在于,烧结混合粉末的成形体,所述混合粉末主要由40至70重量%的含有至少一种选自Y 2 O 3的稳定剂的粉末状ZrO 2的第一组分组成, CaO,MgO,平均粒径为1μm以下,平均粒径为1μm以下的粉末状α-Al2O3粉末的第二成分的平均粒径为1〜30重量%,混合粉末 还可以含有不超过3重量%的SiO 2,不超过0.5重量%的Fe 2 O 3,或不超过0.5重量%的TiO 2,其组合比例不超过3重量% 范围在常压下为1400℃至1600℃,从而生产烧结体,其中存在至少90重量%的存在于其中的ZrO 2颗粒为四方晶体和立方晶体,所述四方晶体与所述立方晶体的比率 结晶 Als至少为1:3,整个烧结体的平均晶粒直径至少为3微米。