서지주요정보
질화규소 결합 탄화규소의 고온 부식 및 열충격 거동 = Hot-corrosion and thermal shock behavior of $Si_3N_4$-bonded SiC
서명 / 저자 질화규소 결합 탄화규소의 고온 부식 및 열충격 거동 = Hot-corrosion and thermal shock behavior of $Si_3N_4$-bonded SiC / 이경근.
저자명 이경근 ; Lee, Gyeong-Geun
발행사항 [대전 : 한국과학기술원, 1999].
Online Access 원문보기 원문인쇄

소장정보

등록번호

8009374

소장위치/청구기호

학술문화관(문화관) 보존서고

MMS 99033

SMS전송

도서상태

이용가능

대출가능

반납예정일

초록정보

In this work, the hot-corrosion behavior of silicon nitride-bonded silicon carbide composite(SCN) in aluminum melt are studied especially on the similar environment to the actual working condition. The thermal shock resistance and cyclic thermal shock behavior of this composite are also studied. The mass decrease of pre-oxidized SCN in the aluminum melt at 750℃ for 120 hr was greater than that of unoxidized one. Si$O_2$ formed during the pre-oxidizing step was corroded in aluminum melt. In case of pre-oxidized SCN, the hot-corrosion of Si$O_2$ was faster as the temperature of melt increased, but the amount of hot-corrosion of Si$O_2$ was same, because the amount of Si$O_2$ degraded was determined by the pre-oxidizing step. By the hot-corrosion in the aluminum melt at 750℃ and 850℃, the compressive strength of unoxidized SCN was decreased to 4 % and 6 %, respectively. However, in case of pre-oxidized SCN, the compressive strength was decreased to 37 % and 53 %, respectively. The hot-corrosion of Si$O_2$ formed during the pre-oxidizing step caused the decrease of the compressive strength of SCN. The change of mass increase showed parabolic behavior as time. The pore neck of porous silicon nitride was blocked by the Si$O_2$ in the oxidizing step at 1200℃, and the effective area of silicon nitride was decreased by the blocking. The activation energy of the oxidation of SCN was determined to be 223 kJ/mol, and this activation energy was thought to be that of the diffusion of oxygen through $SiO_2$, which was formed at the surface of silicon nitride during oxidation. In the experiments of water quenching test of SCN composite, the initial four-point flexural strength was found to be 24.6 MPa, the critical thermal shock temperature difference was about 425℃, and remained four-point flexural strength was 18.5 MPa. In case of reaction bonded silicon nitride(RBSN), the critical thermal shock temperature difference was determined to 253℃ by the calculation of theoretical equation. Due to presence of silicon carbide particles in SCN composite, the theoretical critical thermal shock temperature difference was increased to 336℃, because the thermal stress in the specimen was decreased by fast heat transfer through silicon carbide. Experimental results obtained from cyclic thermal shock test of SCN composite show that the four-point flexural strength of composite was decreased as the number of cycle between 750℃ of aluminum melt and room temperature air was increased. However, after 100 cycles of thermal shock test, the four-point flexural strength was decreased to 13.7 MPa, which was 57 % of initial four-point flexural strength. The repeated thermal stress by the cyclic heating and cooling caused the decrease in strength.

서지기타정보

서지기타정보
청구기호 {MMS 99033
형태사항 iv, 81 p. : 삽도 ; 26 cm
언어 한국어
일반주기 부록 : 1, Calculation data of scn composite
저자명의 영문표기 : Gyeong-Geun Lee
지도교수의 한글표기 : 조건
지도교수의 영문표기 : Kurn Cho
학위논문 학위논문(석사) - 한국과학기술원 : 재료공학과,
서지주기 참고문헌 : p. 76-80
주제 질화규소 결합 탄화규소
알루미늄 용탕
고온 부식
산화
열충격
Silicon nitride-bonded silicon carbide
Aluminum melt
Hot-corrosion
Oxidation
Thermal shock
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