1986 Fiscal Year Final Research Report Summary
Production of silicon carbide whiskers via silicon sulfide intermediate
| Project/Area Number |
60550558
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
無機工業化学
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| Research Institution | Nagasaki University |
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Principal Investigator |
MAKOTO Egashira Nagasaki University, Faculty of Engineering, 工学部, 助教授 (60037934)
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| Co-Investigator(Kenkyū-buntansha) |
HIROAKI Katsuki Nagasaki University, Faculty of Engineering, 工学部, 助手 (10124827)
岩永 浩 長崎大学, 教養部, 教授 (40039772)
HIROSHI Iwanaga Nagasaki University, Faculty of Liberal Arts
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| Project Period (FY) |
1985 – 1986
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| Keywords | Silicon carbide whisker / Metallic silicon / Silicon sulfied intermediate / Hydrocarbons / Vapor phase growth / Stacking faults / Tensile strength / 成長機構 |
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| Research Abstract |
A new process of silicon carbide whisker production was developed by reactions via gaseous silicon sulfide intermediates (Si <S_2> or SiS). The following results were obtained on optimum conditions for the whisker production, structure and mechanical properties of the whisker, and the growth mechanism ;
1. Optimum Conditions : In the reaction of metallic silicon and propylene at 1200-1350゜c, the whiskers well produced when hydrogen sulfide was mixed in the reaction system. The yield was maximum under the conditions of reaction temperature 1300゜c, concentration of propylene ca. 6% (in <H^2> ), and concentration of hydrogen sulfide 4-5%. Conversion of carbon atoms fed as propylene into SiC was about 16%. The whiskers also well produced by thermal decomposition of sulfur-containing silicone oils at 1300゜c, the yield being larger for the oils containing a larger amount of sulfur.
2. Structure and Properties : The products were white and woolly whiskers having high aspect ratios ; the width 0.1-3 <mu> m and the length 0.2-10cm. The growth axis was <111> of the <beta> -form. Many stacking faults was observed obliquely against the whisker axis by electron transmission microscope, but there were no dislocations responsible for lowing the mechanical strength. Tensile strength was 170-1460kg/ <mm^2> for the whiskers of 1.8-2.9 <mu> m in width, the values being approximately the same as those obtained by other reactions. The existence of stacking faults exerted no influence on the mechanical properties.
3. Growth Mechanism ; Scanning and transmission electron microscopic observations revealed that the whiskers carried no particles characteristic of the VLS growth. Taking account of this observation as well as thermodynamic consideration, it was suggested that the present <beta> -SiC whiskers grew by a VS mechanism via volatile <SiS_2> or SiS intermediates.
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