서지주요정보
대기압 가압소결에 의한 T-15 고속도강 분말의 소결에 미치는 붕산첨가의 영향 = Effect of boric acid addition on the sintering of T-15 high speed steel powder by cap process
서명 / 저자 대기압 가압소결에 의한 T-15 고속도강 분말의 소결에 미치는 붕산첨가의 영향 = Effect of boric acid addition on the sintering of T-15 high speed steel powder by cap process / 이욱성.
저자명 이욱성 ; Lee, Wook-Seong
발행사항 [서울 : 한국과학기술원, 1985].
Online Access 제한공개(로그인 후 원문보기 가능)원문

소장정보

등록번호

4103296

소장위치/청구기호

학술문화관(문화관) 보존서고

MMS 8533

SMS전송

도서상태

이용가능

대출가능

반납예정일

초록정보

Gas atomized T-15 high speed steel powder was blended with solution of 0-1% boric acid dissolved in methanol and dried at 50℃. The powder mixture was filled into pyrex glass mould, vacuum-degassed at 450℃ and sealed. The sealed specimen was embedded in alumina boat tightly filled with graphite powder. The boat with specimen was put into the tube furnace heated to a constant temperature between 1175℃ and 1225℃, and sintered for 16 hours in air. And the microstructures of the sintered specimens were studied. For densifying above 94% of theoretical density by CAP process, the T-15 high speed steel powder was required to be fine below 325 mesh size and to be added more than 0.05% of boric acid, and the sintering temperature should be 1200℃. Densification of the high speed steel powder, sintered at 1200℃ for 16 hours, was considerably accelerated with increase of boric acid content up to 1%. The saturation of densification and the growth of austenite grains and primary carbides appeared with increase of boric acid at the same sintering condition. Boric acid was transformed into liquid boron oxide, $B_2O_3$, after vacuum degassing and the packing density of the spherical high speed steel powder was considered to increase with increase of liquid boron oxide because the softened pyrex mould pressed the powder compact by the atmospheric pressure. During sintering at high temperature, liquid boron oxide was considered to be reduced to metallic boron by saturated carbon in the high speed steel and to form a liquid phase. This liquid phase seemed to accelerate the densification. Model experiment to confirm the liquid formation was performed by superposing a T-15 high speed steel powder compact with 10\% boric acid on the fully densified body and sintering at 1200℃ for 1 hour. It was confirmed that liquid phase of low dihedral angle was formed by the addition of excess boric acid and penetrated along the grain boundaries of the sintered high speed steel body. Composition analysis of the liquid phase by EDAX showed that this liquid phase had high content of carbide forming elements such as tungsten, chromium, vanadium, and iron. Therefore the liquid phase was considered to be the iron-carbide-boride eutectic liquid.

서지기타정보

서지기타정보
청구기호 {MMS 8533
형태사항 iii, 39 p. : 삽도 ; 26 cm
언어 한국어
일반주기 저자명의 영문표기 : Wook-Seong Lee
지도교수의 한글표기 : 은광용
지도교수의 영문표기 : Kwang-Yong Eun
학위논문 학위논문(석사) - 한국과학기술원 : 재료공학과,
서지주기 참고문헌 : p. 38-39
주제 Sintering.
Tool-steel.
Microstructure.
Boric acid.
가압 소결. --과학기술용어시소러스
고속도강. --과학기술용어시소러스
첨가물 효과. --과학기술용어시소러스
미세 구조. --과학기술용어시소러스
Densification.
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