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ホットプレスLaB₆セラミックスの機械的及び電気的特性
No full textIn this study, pure LaB6 ceramic powder was hot-pressed to prepare a sintered compact when the press pressure was changed from 7.05 to 28.17 MPa, and the mechanical and electrical properties were revealed.The relative density improved in proportion to the press pressure, and 82.9-95.3% was obtained. When the hot-press pressure is 28.17MPa, the sintered compact has a relative density of 95.3%, Vickers hardness 15.2GPa, flexural strength 216MPa, fracture toughness 2.06MPa・m1 / 2, Young's modulus 204GPa, shear modulus 84.8 GPa, surface roughness Ra 297nm and electric conductivity 7.67MS/m. It is characterized by having high electrical conductivity.application/pdfdepartmental bulletin pape
CrB,CrB₂,Cr₂N,CrSi₂セラミックスのホットプレス焼結とその機械的・電気的特性
No full textIn order to investigate the mechanical and electrical properties of CrB, CrB₂, Cr₂N, and CrSi₂ of Cr-based ceramics with good oxidation resistance, hot press (HP) sintering was performed under the condition of pressure of 28.2 MPa for 3.6 ks at a temperature of 85% of the melting point [℃] in a Ar atmosphere using each pure powder. As a result, CrSi2 has good mechanical properties as a whole, with a flexural strength of 343 MPa, a fracture toughness value of 3.44 MPa∙m1/2, and a surface roughness (Ra) of 70.0 nm. On the other hand, as for the electrical characteristics, CrB₂ had a high electrical conductivity of 2.44 MS/m, and CrSi₂ had a low one of 0.072 MS/m. The oxidation temperature of these ceramics is 1000°C or higher. Therefore, Cr-based ceramics are suitable for materials in fields where oxidation resistance is required.application/pdfdepartmental bulletin pape
超音波加振型加圧焼結法によるNi粉末の焼結促進と高強度化
No full textIn this research, focusing on the vibrational energy (acoustic energy) of ultrasonic waves that can be generated with a relatively simple device, hot-press sintering of Ni metal powder under assisting this energy is examined to improve sintering promotion and the strength by an experiment. A pure Ni metal powder is packed in a cylindrical mold, then, heated to a hot-press temperature in inert Ar gas. The hot pressing at 40 MPa under ultrasonic vibration (using ultrasonic transducer with inherent frequency of 20 kHz and 28 kHz) was applied to the metal powder for a predetermined sintering time. The relative density, tensile strength and electrical conductivity of the sintered compact were investigated. As a result, it is able to promote sintering and increase the strength by the aid of the ultrasonic waves.application/pdfdepartmental bulletin pape
純B₄Cセラミックスホットプレス焼結体の機械的・電気的特性‐ホットプレス圧と雰囲気圧の影響‐
No full textIn order to understand the characteristics of B₄C monopoly, the effects of hot-press (HP) pressure and Ar inert atmospheric pressure on the mechanical / electrical properties of pure B4C powder compact were investigated using the HP method. The sintering temperature was constant at 1950 ° C, and the sintering time was 3.6 ks. When the press pressure was increased, the densification occurred rapidly and the relative density reached 99.3% even at a low HP pressure of about 23.4 MPa. Furthermore, when the press pressure was 31.2 MPa, a relative density of 99.9%, a flexural strength of 502 MPa, and a hardness of 38.5 GPa were obtained. By using the HP method, B4C is able to obtain high properties and a smooth surface (mirror surface) by the HP sintering without adding a sintering aid.application/pdfdepartmental bulletin pape
来街目的施設および回遊トリップ数が駐車場選択に与える影響‐長野市中心市街地を対象として‐
No full textThe purpose of this study is to find the right place for a parking lot that does not pair the mobility of central Nagano． This is to control the location of the parking lot ithout impairing the movement behavior of car users， eliminate the congestion of cars on the roads in the city， and promote the movement behavior of pedestrians． The purpose of this study is to collect the questionnaire surveys conducted for parking lot users in the city area and use it as a material for creating guidelines for the maintenance of parking lots and streets in the central city area of Nagano City．application/pdfdepartmental bulletin pape