摘要:
A positive ceramic semiconductor device having positive temperature coefficient of resistance comprises a pair of electrodes provided on a ceramic semiconductor substrate. One of the paired electrodes which is to serve as the positive pole is basically constituted by at least an electrically conductive layer of silver-palladium series containing silver and palladium at a predetermined ratio. For preventing a localized current concentration from occurring in the current conducting state, improvement is made as the structure of the positive pole electrode ormed of the electrically conductive material of silver-palladium series and/or the structure of the negative pole electrode. Silver-migration phenomenon on the positive ceramic semiconductor substrate as well as degradation of the mechanical strength thereof is positively prevented.
摘要:
Anti-reducing semiconducting porcelain having a positive temperature coefficient of resistance comprises a barium titanate composition, and a flux containing 0.14 to 2.88 parts by weight of TiO.sub.2 0.1 to 1.6 parts by weight of Al.sub.2 O.sub.3 and 0.1 to 1.6 parts by weight of SiO.sub.2 per 100 parts by weight of the barium titanate composition. It has a high positive temperature coefficient of resistance which does not show any appreciable change in the presence of a reducing atmosphere, such as hydrogen gas or gasified gasoline. It need not be isolated from a reducing atmosphere by a plastic or metallic enclosure, but can be exposed thereto. The flux may further contain a zinc, potassium or lithium compound.
摘要:
An alumina sintered body comprises alumina crystals as a main phase and a grain boundary phase made up of crystalline Y2Si2O7 and amorphous SiO2 at grain boundaries of the alumina crystals wherein when the alumina sintered body is taken as 100 wt %, the high melting phase is present in the range of from 0.1 wt % to 15 wt %. There is also provided a method for preparing the alumina sintered body, which method comprising a first mixing step P1 of mixing, at least, a yttria powder having an average particle size of 60 to 100 nm and a silica powder having a given average particle size to provide a mixed slurry and a second mixing step of further mixing an alumina powder having an average particle size of 0.5 to 1.0 μm in the mixed slurry.
摘要:
An alumina sintered body comprises alumina crystals as a main phase and a grain boundary phase made up of crystalline Y2Si2O7 and amorphous SiO2 at grain boundaries of the alumina crystals wherein when the alumina sintered body is taken as 100 wt %, the high melting phase is present in the range of from 0.1 wt % to 15 wt %. There is also provided a method for preparing the alumina sintered body, which method comprising a first mixing step P1 of mixing, at least, a yttria powder having an average particle size of 60 to 100 nm and a silica powder having a given average particle size to provide a mixed slurry and a second mixing step of further mixing an alumina powder having an average particle size of 0.5 to 1.0 μm in the mixed slurry.
摘要:
An alumina compound sintered compact, having a principal component of alumina, a method of manufacturing the same, and a spark plug employing such an alumina compound sintered compact are disclosed. The alumina compound sintered compact contains alumina, mullite, zircon, zirconia and a specified metal oxide composed of an oxide of at least one element selected from Group III elements excepting Mg, Ca, Sr, Ba and actinoid, wherein the alumina compound sintered compact contains 0.5 to 10 total parts by weight of mullite, zircon and zirconia, 0.5 to 10 parts by weight of the specified metal oxide and a balance of substantially alumina based on 100 parts by weight in total. The spark plug for an internal combustion engine includes a porcelain insulator made of the alumina compound sintered compact.
摘要:
An alumina sintered body of the present invention has alumina crystals as a main phase and an amorphous grain boundary glass phase. The amorphous grain boundary glass phase is a grain-boundary glass phase having an amorphous glass component in which at least one of either CaO or MgO is added to SiO2, and at least one type of oxide selected from rare-earth elements and elements in Group IV of the periodic table included in the amorphous glass component as a specific component. When a composition ratio of the main phase and the amorphous grain boundary glass phase is alumina:amorphous glass component:specific component=a:b:c (a+b+c=100% by weight), in a triangular coordinate of which peaks are alumina, the amorphous glass component, and the specific component, a point (a,b,c) is within a range surrounded by four points, A(98.0,1.0,1.0), B(90.0,5.0,5.0), C(93.5,5.0,1.5), and D(97.8,2.0,0.2).
摘要翻译:本发明的氧化铝烧结体具有氧化铝晶体作为主相和无定形晶界玻璃相。 无定形晶界玻璃相是具有非晶玻璃成分的晶界玻璃相,其中,向SiO 2中添加CaO或MgO中的至少一种,并且选自组中的稀土元素和元素中的至少一种氧化物 包括在非晶玻璃组分中的周期表的IV作为特定组分。 当主相和非晶晶界玻璃相的组成比为氧化铝:非晶玻璃组分:特定组分= a:b:c(a + b + c = 100重量%)时,其三角坐标为峰 (a,b,c)在四点A(98.0,1.0,1.0),B(90.0,5.0,5.0),C (93.5,5.0,1.5)和D(97.8,2.0,0.2)。
摘要:
A highly accurate reduction resistant thermistor exhibiting stable resistance characteristics even under conditions where the inside of a metal case of a temperature sensor becomes a reducing atmosphere, wherein when producing the thermistor comprised of a mixed sintered body (M1 M2)O3.AOx, the mean particle size of the thermistor material containing the metal oxide, obtained by heat treating, mixing, and pulverizing the starting materials, is made smaller than 1.0 μm and the sintered particle size of the mixed sintered body, obtained by shaping and firing this thermistor material, is made 3 μm to 20 μm so as to reduce the grain boundaries where migration of oxygen occurs, suppress migration of oxygen, and improve the reduction resistance.
摘要:
The thermistor element of the present invention is composed of a mixed sintered body aM1M2O3bY2O3 of a composition M1M2O3 (wherein M1 is Y, and M2 is at least one element selected from the elements such as Cr, Mn, Ti, etc.) as a perovskite compound and Y2O3, wherein molar fractions a and b satisfy the relations 0.05≦a
摘要翻译:本发明的热敏电阻元件由M 1 M 2 O 3组成的混合烧结体aM 1 M 2 O 3 bY 2 O 3(其中M 1为Y,M 2为 选自Cr,Mn,Ti等的元素中的至少一种元素)和作为钙钛矿型化合物的Y 2 O 3,其中摩尔分数a和b满足0.05 <= a <1.0,0
摘要:
A solid object carrying a catalyzer thereon is placed in a closed reaction chamber into which test gases are supplied and is heated up to a temperature of 1000.degree. C. Adsorbates are formed on the surface of the solid object under the test gas flow in the closed reaction chamber. Infrared radiations radiated from the adsorbates are emitted through an infrared-transmissive window hermetically formed on a wall of the closed reaction chamber, and are analyzed by an infrared radiation spectrometer and observed by a microscope. The infrared-transmissive window is cooled down by a cooling device attached thereto so that the temperature of the window does not exceed a certain level, e.g., 200.degree. C. Thus, the adsorbates formed on the solid object can be detected and analyzed under conditions where the test gas is actually flowing and the temperature of the solid object is elevated up to a high level. Since the infrared-transmissive window is cooled down and prevented from being broken by heat, the detection and analysis of the adsorbates are performed safely.
摘要:
An alumina composite sintered body 1 in which fine particles 2 are dispersed in the crystal grains 4 and/or at the crystal grain boundaries 3 of an alumina sintered body obtained by sintering alumina crystal grains 4; an evaluation method thereof; and a spark plug using the alumina composite sintered body 1. Arbitrary regions in the cross-section of the alumina composite sintered body 1 are taken as analysis surfaces, and when the cross-sectional areas of the fine particles 2 contained in each analysis surface are measured, the ratio of the cross-sectional areas occupying in the area of the analysis surface is from 1 to 20%; when the cross-sectional areas of the fine particles 2 contained in each of analysis surfaces adjacent to each other are measured, and the cross-sectional area is converted into a circle having the same area, the diameter of the circle is from 0.1 to 4 μm; and when the concentration A (wt %) of the fine particles 2 contained in each analysis surface is compared with the concentration B (wt %) of the fine particles 2 used at the production, the difference between the concentration A and the concentration B is within ±20 wt %.