| Co-Investigator(Kenkyū-buntansha) |
JIANG Weihua Extreme Energy-Density Research Institute, Nagaoka University of Technology, Associate Professor, 極限エネルギー密度工学研究センター, 助教授 (90234682)
HARADA Nobuhiro Engineering Department, Nagaoka University of Technology, Associate Professor, 工学部, 助教授 (80134849)
SAITOH Hidetoshi Engineering Department, Nagaoka University of Technology, Associate Professor, 工学部, 助教授 (80250984)
IMADA Go Engineering Department, Nagaoka University of Technology, Assistant, 工学部, 助手 (60262466)
SUEMATSU Hisayuki Extreme Energy-Density Research Institute, Nagaoka University of Technology, Associate Professor, 極限エネルギー密度工学研究センター, 助教授 (30222045)
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| Research Abstract |
Technique to deposit thin films by pulsed ion-beam ablation plasma has been proposed and demonstrated in Extreme Energy-Density Research Institute (EDI) for the first time, which was called intense pulsed ion-beam evaporation (IBE). Until now, we revealed that a density of the ablation plasma generated by IBE method is approximately 10^<18> cm^<-3>, and a high pressure above approximately 10 GPa is applied in a target due to the reaction of the ablation plasma. In general, high hardness materials such as diamond are known to have stable phase under the conditions of high temperature and pressure. Therefore, this investigation was done to synthesize high hardness materials by using the ablation plasma, which was generated by the IBE method.
Boron carbide (B_4C) having the highest hardness next to diamond is one of difficult materials to be crystallized. Accordingly, by using the IBE method, we undertaken to prepare crystallized B_4C thin films without heat-treatment. As a result, the B_4
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C thin films, which were crystallized without heat-treatment before and after deposition, had high hardness (Vickers hardness of 2,300). Such result is the first example in the world. Additionally, in the measurements of thermoelectric properties, the power factor of the B_4C thin films synthesized by the IBE method was observed to be approximately 3 times higher than that of B_4C samples in previous papers.
Carbon, which has many allotropes as graphite, diamond and diamond-like-carbon (DLC), is known to change structure in dependence on temperature or pressure. Accordingly, we researched on the surface modification of highly oriented pyrolytic graphite (HOPG) targets, when ion-beam was irradiated on the HOPG targets. From the results of surface observation, spherical or columnar graphite approximately 1 μm in diameter was found to exist on the irradiated HOPG targets. Since carbon is known to melt at ~5000 K and ~11 MPa, the surface of the HOPG targets can be stated to be the conditions of high temperature and pressure by irradiating ion-beam. Additionally, in the surface of the HOPG targets, disorder structure was clarified to increase with increasing in ion-beam energy density. Less
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