• 보존과학연구
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• 통권21호
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• pp.101-118
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• 2000

Stone cultural properties(pagoda, Buddhist statue etc.) is moved in original place for many reasons and restored after taking to pieces for structural safety. With the movement and restoration after taking to pieces, the cast iron is used for the sake of a fixation and horizontality. The stone cultural properties are spoiled the beauty and accelerated the weathering because of the corrosion product of cast iron. So we need to substitute for the improved property in all aspects. We are executed the corrosion test and inquired the property of material on the usable material for the shim of stone cultural properties. That is the Cast iron, Stainless steel, Titanium and Fiber Reinforced Plastics. In the result of the physical property and strength, the Stainless steel and Titanium was superior to the Cast iron. And the Stainless steel and Titanium was slower than the Cast iron in the corrosion velocity for the acid, salt and rain. If the shim is substitute the Stainless steel or Titanium for the Cast iron, the stone cultural properties are able to reduce the pollution of stone cultural properties by corrosion product and should not happen in the matter of stone pagoda.

• Nuclear Engineering and Technology
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• 제56권3호
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• pp.941-948
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• 2024

The effects of radiation on the corrosion of canister materials were investigated for the reliable disposal of high-level radioactive waste. The test specimens were gamma-irradiated at a very low dose rate of approximately 0.1 Gy/h for six and twelve months. The copper and cast iron species were less corroded when irradiated. It is hypothesized that gamma rays suppress the formation of lower-enthalpy species like metal oxides and activate reductive reactions. In contrast, it was difficult to evaluate the effect of radiation on the corrosion of titanium and stainless steel.

• 한국주조공학회지
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• 제18권6호
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• pp.563-569
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• 1998

A Study on microstructure and elevated temperature strength of 18Cr-2Mo ferritic stainless steel castings strengthened by alloying small amounts of titanium and carbon, has been conducted. The morphology of titanium carbides showed spherical in shape and their distribution depended on the amount of alloying elements. Maximum density ($7{\times}10^5/cm^2$) of titanium carbides has been formed in the alloy containing 2.0 wt.% titanium and 0.5 wt.% carbon as alloying elements and the size of carbide particles is in the range of 0.5 to $3.0\;{\mu}m$. High temperature tensile and fatigue strength of this alloy were the highest among the alloys tested in this research. The fracture mode of the alloys containing alloying elements less that 2.0 wt.% titanium and 0.5 wt.% carbon showed intercrystalline fracture at room temperature, while the alloys containing higher amounts of alloying elements showed transcrystalline fracture. All of the alloys showed creep or ductile rupture mode at elevated temperature.

• 한국주조공학회지
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• 제44권1호
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• pp.9-15
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• 2024

본 연구에서는 망간강을 소재로 하는 부품의 수명향상을 위해 망간강에 Ti의 첨가량을 변화하여 망간강을 주조하였으며, 주조한 소재의 특성을 확인하기 위하여 인장 및 표면 특성 그리고 베어링률 등 가공특성에 대해 조사하였다. 고망간강에 Ti 첨가 시 0.5%를 초과 시 결정립 미세화로 인한 합금의 강도가 향상되었으며 내부에 미세 탄화물이 형성시킴으로써 Mn만 첨가된 합금에 비해 표면의 마모에 대한 저항성을 높이는 결과를 나타냄을 확인하였다. 망간강에서 Ti의 함유량이 증가함으로 인해 인장강도가 증가함에는 큰 차이가 없었으나 마모성의 부분에서는 Ti이 Mn에 비해 마모성에는 미량이지만 더 큰 영향을 끼치며 Ti의 함량에 따라 탄화물의 크기 및 분포가 조대하고 균일하게 분포하였다. 망간강을 소재로 하는 부품의 수명향상을 위해 망간강에 Ti 첨가함으로써 강도 및 표면특성을 향상시킬수 있음을 확인하였다. Ti이 수지상정 결정립의 미세화로 인한 내마모성이 우수한 재질을 개발하는데 효과있음을 알 수 있었다. Ti가 첨가된 샘플에서 탄화물은 표면 거칠기에 대한 내성을 증가시키는 것으로 나타났으며 Mn강의 특성상 표면경화가 일어나기 시작하여 수명이 연장되는 것으로 보인다.

• 한국재료학회지
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• 제9권2호
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• pp.199-204
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• 1999

As the engine design change to get high efficiency and performance of commercial diesel engine, surface wear of the cam follower becomes an important issues as applied load increasing at the contact face between cam follower and cam. Purpose of this study is the developing of the ceramic cam follower made of silicon nitride ceramic which is more wear resistant than the cast iron and sintered cam follower. Ceramic cam follower was made by direct brazing of thin ceramic disk to steel can follower body using active bracing alloy. Effect of joining condition on the interfacial phases and joining strength wer examined at bvarious joining temperatures, times, and cooling rates. Crowning resulted from the difference of thermal expansion coefficient after direct brazing without using any stress-relieving inter layer was measured. Interfacial phases are mainly titanium silicide and titanium nitride which are the products between active metal(Ti) in brazing alloy and silicon nitiride. Maximum joining strength of the ceramic metal joint, measured by DBS method, was 334MPa. Crowning(R) of the prototype ceramic cam follower was 1595mm. As machining for crowning is not necessary, production cost can be reduced.

• Composites Research
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• 제33권5호
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• pp.251-255
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• 2020

본 연구에서는 용융가압함침공정을 이용하여 제조된 TiC 세라믹 입자강화 철강복합재를 제조하고 상용구상흑연주철과 비교를 위하여 미세조직 분석 및 경도 등 기초물성과 선박 해양 분야등의 적용가능성 검토를 위하여 염수환경에서의 부식 특성에 관한 연구를 진행하였다. 염수환경에서의 부식특성 비교 결과 구상흑연주철 대비 부식전위와 부식전류밀도 모두 낮은 값을 나타내었고, 낮은 연간부식률을 통하여 TiC-Fe 금속복합재의 내식성이 더 뛰어난 것을 확인하였다.

• 한국분말재료학회지
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• 제5권4호
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• pp.340-344
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• 1998

Along with the growth of conventional ferrous powder metallurgy (PM), PM of aluminum alloys has been intensively investigated in Japan. Although rapidly solidified aluminum alloy powder was first used in the USA,/sup 1)/ commercialization for consumer market was first realized in Japan./sup 2)/ In order to achieve the viable cost-performance including Near Net Shape (NNS) formability, we developed three processes, powder extrusion, powder forging and sintering. The new powder extrusion process does not use either capsulation or vacuum degassing. The new powder forging does not need lateral flow. The new sintering process does not use liquid phase. The performance achieved by the processes is outstanding mechanical or physical properties that has potential to substitute cast iron, steel, titanium Metal Matrix Composite (MMC) or Ingot Metallurgy (IM) aluminum alloys. Cooperation with customers, powder suppliers and research associations contributed to the advancement of PM aluminum alloys in Japan.

• 대한치과교정학회지
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• 제35권5호
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• pp.381-387
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• 2005

본 연구의 목적은 교정치료 초기에 사용되는 스테인레스스틸, 다가닥철선. 초탄성 NiTi, 열활동성 NiTi재료로 이루어진 총 4가지 호선의 초기 치료효과를 비교하기 위하여 시행되었으며, 실험의 설계는 전향적 임상 실험(prospective randomized clinical trial)으로서 브라질 리오데자네이로 주립 치과대대학에 내원한 45명의 고정식 교정장치 환자를 대상으로 시행되었다. 각 호선의 재료는 환자의 치열에 무작위로 배당되었는데 스테인레스스틸은 20명, 다가닥철선은 22명, 초탄성 NiTi는 22명, 열활동성 NiTi는 20명에게 할당되었고. 8주 후에 모형을 다시 제작한 후 3차원 디지털영상 장비를 이용하여 모형의 치관에 설정된 해부학적 지표의 변화를 측정하였는데 치료전 및 치료후 치열불규칙지수(Dental Irregularity Index)의 차이로 초기 교정치료 효과를 비교하였다. 분산분석을 시행하여 불규칙지수의 변화를 살펴본 결과 호선의 재료에 따른 초기 치료 효과는 유의한 차이가 나타나지 않았다