摘要:
[PROBLEMS] To provide a process for recovering, by a simple means, the light transmission properties of an aluminum nitride sintered body which light transmission properties have been lowered by processing after sintering. [MEANS FOR SOLVING PROBLEMS] A process for producing an aluminum nitride sintered body having improved light transmission properties of the present invention comprises subjecting an ordinary aluminum nitride sintered body to thermal treatment in an inert atmosphere at a temperature of from 1300 to 1400°C for at least 1 hr. A cover for light sources of the present invention comprises a hollow aluminum nitride sintered body having a light transmittance in the visible light region of at least 87%, which body is obtainable by thermally treating a hollow aluminum nitride sintered body in an inert atmosphere at a temperature of 1300 to 1400°C for at least 1 hr.
摘要:
A cutting tool insert which can, for example, be used for machining of hardened steel, hot and cold working tool steel, die steel, case hardened steel, high speed steel and ductile grey cast iron and composed of a composite comprising a cBN-phase and a binder phase comprising a titaniumcarbonitride phase and a TiB 2 phase is disclosed. In the XRD pattern from the composite using CuKa-radiation, the peak height ratio of the strongest (101) TiB 2 peak and the strongest cBN (111) peak is less than 0.06, the (220) peak from the titanium carbonitride phase in the XRD-pattern intersects both vertical lines of the PDF-lines of TiC (PDF 32-1383) and TiN (PDF 38-1420) and the lowest intersected point height is at least 0.15 of the maximum (220) peak height of the ceramic binder phase. The insert is made by powder metallurgical methods milling, pressing and sintering, the sintering being performed at lowest possible temperature for shortest possible time necessary to obtain a dense structure.
摘要:
A high-purity rare earth metal oxide material powder of purity of 99.9 % or over, of which Al content is 5 -100 wtppm in metal weight and Si content is 10 wtppm or under in metal weight, and a binder are used to prepare a molding body of which molding density is 58 % or over of the theoretical density. The binder is eliminated by thermal treatment, and then the molding body is sintered in an atmosphere of hydrogen or a rare gas or a mixture of them or in a vacuum at a temperature being not lower than 1450°C and not higher than 1700°C for 0.5 hour or over to prepare A transparent sintered rare earth metal oxide body represented by a general formula R 2 O 3 (R being at least one element of a group comprising Y, Dy, Ho, Er, Tm, Yb and Lu).
摘要翻译:纯度为99.9%以上的高纯度稀土金属氧化物材料粉末,其中Al含量为金属重量为5〜100重量ppm,Si含量为金属重量为10重量ppm以下,粘合剂用于制备 成型体的成型密度为理论密度的58%以上。 通过热处理去除粘合剂,然后将模塑体在氢气或稀有气体或它们的混合物的气氛中或在不低于1450℃且不高于1700℃的真空中进行烧结 0.5小时以上制备由通式R 2 O 3表示的透明烧结稀土金属氧化物体(R为包含Y,Dy,Ho,Er,Tm,Yb和Lu的至少一种元素)。
摘要:
A SiAlON composite according to an embodiment of the present disclosure comprises a SiAlON phase including α-SiAlON phase, β-SiAlON phase and grain boundary phase. The SiAlON composite is prepared from a starting powder mixture including a silicon nitride powder and at least one powder providing aluminum, oxygen, nitrogen, yttrium (Y) and erbium (Er) to the SiAlON composite. The SiAlON composite contains the SiAlON phase of at least 90 vol%, z-value of the β-SiAlON phase ranges between 0.27 and 0.36 and thermal diffusivity of the SiAlON composite is equal to or greater than 2.4 (mm2/sec) and equal to or less than 5.2 (mm2/sec).
摘要:
Disclosed is an aluminum nitride substrate for a circuit board, the substrate having aluminum nitride crystal grains with an average grain size of 2 to 5 µm and a thermal conductivity of at least 170 W/m·K. The aluminum nitride substrate does not include a dendritic grain boundary phase and has a breakdown voltage of at least 30 kV/mm at 400 °C. Also provided is a method for producing the aluminum nitride substrate, including the steps of heating a raw material containing an aluminum nitride powder to 1500 °C at a pressure of at most 150 Pa, then increasing and holding the temperature at 1700 to 1900 °C in a pressurized atmosphere of at least 0.4 MPa using a non-oxidizing gas, then cooling to 1600 °C at a cooling rate of at most 10 °C/min.
摘要:
A polycrystalline sintered ceramic including (A) a garnet phase and (B) a perovskite, monoclinic or silicate phase wherein fine grains of phase (B) are included and dispersed in phase (A) is used as a wavelength converting member. Since the light transmitting through the wavelength converting member is scattered at the interface between the garnet phase and the perovskite, monoclinic or silicate phase, a light emitting device including the wavelength converting member produces light of more uniform color with a minimized loss thereof.
摘要:
A polycrystalline sintered ceramic including (A) a garnet phase and (B) a perovskite, monoclinic or silicate phase wherein fine grains of phase (B) are included and dispersed in phase (A) is used as a wavelength converting member. Since the light transmitting through the wavelength converting member is scattered at the interface between the garnet phase and the perovskite, monoclinic or silicate phase, a light emitting device including the wavelength converting member produces light of more uniform color with a minimized loss thereof.
摘要:
A semiconductor ceramic of the present invention includes a Ba m TiO 3 -based composition, as a main component, having a perovskite structure represented by general formula A m BO 3 . The molar ratio m between an A site and a B site satisfies 1.001 ≤ m ≤ 1.01. Part of Ba constituting the A site is replaced with Bi, Ca, a rare-earth element, and at least one of Li and Na. The content of the Ca when the total number of moles of the elements constituting the A site is 1 mole is 0.05 to 0.20 (preferably 0.125 to 0.175) on a molar ratio basis. A PTC thermistor includes a component body 1 formed of the semiconductor ceramic. Accordingly, there is provided a lead-free semiconductor ceramic that substantially does not contain lead and that has desired PTC characteristics and high reliability,
摘要翻译:本发明的半导体陶瓷包括具有由通式A m BO 3表示的钙钛矿结构作为主要成分的Ba m TiO 3基组合物。 A位点与B点之间的摩尔比m满足1.001‰‰‰1.01。 构成A位点的Ba的一部分被Bi,Ca,稀土元素和Li和Na中的至少一种所取代。 构成A位的元素的总摩尔数为1摩尔时,Ca的含量为摩尔比为0.05〜0.20(优选为0.125〜0.175)。 PTC热敏电阻包括由半导体陶瓷形成的部件主体1。 因此,提供了一种基本上不含铅并且具有期望的PTC特性和高可靠性的无铅半导体陶瓷,