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규조토를 주원료로 사용한 서로 다른 조성비의 세라믹 슬러리를 압출성형하여 내열보호관을 제조하고, 기계적 강도, 미세구조, 탄소분석을 하였다. 입도가 50~100 ㎛인 다공성 규조토를 60 wt%로 고정하고, 조성물 변수로써 유무기바인더로 silica sol(4.3~7.3 wt%), CMC(Sodium CarboxyMethyl Cellulose 6~9 wt%) 및 paper powder(4.7~7.7 wt%)를 1 wt%씩 변화시켜 최적의 배합비를 얻었다. 시편의 특성을 조사한 결과, 규조토 60 wt%에 silica sol 5.3 wt%, CMC 7 wt%를 첨가하였을 경우, 꺾임강도 7.12 MPa, 탄성율 1090 MPa, 압축강도 7.47 MPa, 탄소 2.3 wt% 이하로 철강산업에서의 온도성분 측정 및 시료 채취를 할 수 있는 용융금속 프로브용 규조토 내열보호관을 제조할 수 있었다.


A heat-resisting diatomite protection tube, using diatomite as a main component, was manufactured through an extrusion molding of ceramic slurry in different component ratios. And its mechanical strength, carbon analysis and microstructural non-homogeneity were investigated. After fixing 60 wt% of porous diatomite whose particle size was 50~100 ㎛, the optimum mixture ratio with composition variables by changing 1 wt% of each component that was silica sol (4.3~7.3 wt%) as an inorganic binder, CMC (Sodium CarboxyMethyl Cellulose 6~9 wt%) as an organic binder and paper powder(4.7~7.7 wt%) was obtained. As a result of the investigation on a composition containing 60 wt% diatomite, 5.3 wt% silica sol, and 7 wt% CMC, a heat-resisting protection tube that could be used as a molten steel probe for measuring the temperature and components of molten steel was developed. The bending strength, compressive strength, and elastic modulus of the protection tube developed, that contained ≤ 2.3 wt% carbon, were 7.1 MPa, 7.5 MPa, and 1090 MPa, respectively.