• 소성∙가공
• /
• 제26권6호
• /
• pp.365-371
• /
• 2017

During sling wear of a ferrous metal, a surface layer is formed. Its microstructure, constituting phases, and mechanical property are different from those of the original wearing material. Since wear occurs at the layer, it is important to characterize the layer and understand how wear rate changes with different layers. Various layers are formed depending on external wear conditions such as load, sliding speed, counterpart material, and environmental conditions. In this research, sliding wear tests of pure iron were carried out against two different counterparts (AISI 52100 bearing steel and $Al_2O_3$) in the air and in an inert Ar gas atmosphere. Pure iron was employed to exclude other effects from secondary phases in steel on the wear. Wear tests were performed at room temperature. Worn surfaces, wear debris, and cross-sections were analyzed after the test. It was found that these two different counterparts and environments produced diverse layers, resulting in significant changes in wear rate. Against the bearing steel, pure iron showed higher wear rate in an Ar atmosphere due to severe adhesion than that in the air. On the contrary, the iron showed much higher wear rate in the air against $Al_2O_3$. Different layers and wear rates were analyzed and discussed by oxidation, severe plastic deformation, and adhesion at wearing surfaces.

• 전기화학회지
• /
• 제10권3호
• /
• pp.175-178
• /
• 2007

Pure iron, Fe-0.4, and 1.2 wt.%Cu alloys were examined by conducting the electrochemical techniques in the weakly alkaline solution, pH9, controlled by $Ca(OH)_2$, solution added with 0.02M NaCl. The $R_P$ measured from ac impedance, selected 10 kHz and 10mHz, in weakly alkaline solutions containing chloride ions indicated that the addition of copper up to 1.2wt.% into the pure iron significantly improved the pitting resistance of iron. In contrast to alloy, the pure iron showed the rapid pitting occurrences in drying period. During the drying period, the corrosion potential of pure iron was shifted to less noble value, pitting initiation.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2005년도 추계학술대회 논문집
• /
• pp.149-153
• /
• 2005

The electron beam machining provides very high resolution up to nanometer scale, hence the E-beam writing technology is rapidly growing in MEMS and nano-engineering areas. In the optical column of the e-beam writer, there are several lenses condensing and focusing electron beams from electron gun with fringing magnetic fields. The polepieces of these lenses are usually made with high purity iron which is hard to fabricate and very expensive. In this paper, the possibility of using polepiece of object lens composed with pure iron and low carbon steel was examined to reduce cost. The magnetic field at object lens was calculated with finite element method, and practical focusing qualities of SEM pictures were observed comparing for the object lens polepieces with pure iron and two type of composed with low carbon steel.

• 헤리티지:역사와 과학
• /
• 제52권3호
• /
• pp.240-251
• /
• 2019

울산 하대고분에서 출토된 판상철부의 미세조직을 금속학적 방법으로 분석하여 제작기술을 살펴보았다. 또한 기존의 판상철부 연구자료와 비교 및 검토하여 판상철부에 적용된 다양한 제작기술을 파악하였다. 울산 하대고분 44호 목곽묘에서 나란히 배열된 상태로 출토된 판상철부 10점을 과학적으로 분석한 결과, 판상철부의 제작기술 체계를 '(1) 순철-형태 가공, (2) 순철-형태 가공-침탄, (3) 순철-형태 가공-침탄-탈탄' 세 가지 유형으로 분류할 수 있었다. 판상철부는 모두 단조에 의해 제작되었고, 순철을 소재로 두드려 형태를 만들었다. 특히 다수의 판상철부는 형태 가공 후 침탄 처리를 통해 재질을 강화시켰는데, 이는 중간 소재 또는 화폐로 통용됨으로써 당시 제철산업의 근간을 이루었던 철강 제품인 것으로 보인다. 한편 형태 가공이나 침탄 이후에는 담금질이 실시되지 않았다는 공통점을 가진다. 순철을 소재로 제작한 판상철부의 미세조직에는 불순 개재물이 다량 포함되어 있고, 비금속 개재물을 성분 분석한 결과, 유리상과 뷔스타이트가 함께 혼재한 철재(鐵滓)의 특징을 보여주므로 제련 공정에서 저온환원법이 적용되었을 가능성이 크다.

• 한국주조공학회지
• /
• 제8권3호
• /
• pp.287-295
• /
• 1988

The experiment was carried out for the purpose of studying the carburization of pure iron ingot and sintered iron powder by solid carbon in the atmosphere of CO gas. The volocity of carburization was estimaed by the diffusion coefficient D calculated by carburization equation. The results obtained were as follow: 1. The higher the carburization temperature, carburization depth and carbon concentration were increased, and the melting zone which had $2.8{\sim}3.4%C$ at the $3{\sim}4mm$ from interface of carburization was formed at $1300^{\circ}C$. 2. The main carburization mechanism of pure iron ingot and the sintered iron powder were proceeded by CO gas up to $1100^{\circ}C$, solid carbon over than $1300^{\circ}C$, respectively. 3. The main carburization mechanism of pure iron ingot at $1200^{\circ}C$ was proceeded by solid carbon, and sintered iron powder was proceeded bs CO gas, however, in case the reaction time, the carburization was proceeded by solid carbon over than 5hrs. 4. The diffusion coefficient D of carbon were $0.559{\times}10^{-6}cm^2.sec^{-1}$ at $1100^{\circ}C$, $0.237{\times}10^{-6}cm^2.sec^{-1}$ at $1200^{\circ}C$, $0.087{\times}10^{-6}cm^2.sec^{-1}$ at $1300^{\circ}C$, in case of pure iron ingot carburized. 5. The diffusion coefficient D of carbon were $0.124\;cm^2.sec^{-1}$ at $1100^{\circ}C$, $0.102\;cm^2.sec^{-1}$ at $1200^{\circ}C$, $0.480\;{\times}10^{-6}cm^2.sec^{-1}$ at $1300^{\circ}C$, in the case of sintered iron carburized at the pressuring $4ton\;/\;cm^2$.

• 기술사
• /
• 제20권4호
• /
• pp.5-11
• /
• 1987

The experiment was carried out for the purpose of studying the carburization of pure iron ingot and sintered iron powder by solid carbon in the atmosphere of $N_2$ gas. The velocity of carburization was estimated by the diffusion coefficient D calculated by carburization equation. The results obtained were as follows ; 1. The briqueted sample of iron fine powder which made by higher pressure, carburization depth and carbon concentration were increased as much, and pure iron shelved the maximum value. 2, The higher the carburization temperature, carburization depth and carbon concentration were increased, and the melting zone which had 3.0~3.3%C at the interface of carburization was formed at 130$0^{\circ}C$. As the pure iron ingot was carburized, the diffusion coefficient D of carbon were 0.211$\times$$10^{-6}$$\textrm{cm}^2$ㆍsec$^{-1}$ at 120$0^{\circ}C$ and 0.391$\times$$10^{-6}$$\textrm{cm}^2$ㆍsec$^{-1}$ at 130$0^{\circ}C$, respectively. 4. As the sintered iron powder was carburized at the pressure of 4 ton/$\textrm{cm}^2$, the diffusion coefficient of carbon were 0.157$\times$$10^{-6}$$\textrm{cm}^2$ㆍsec$^{-1}$ at 120$0^{\circ}C$ and 0.103$\times$$10^{-5}$$\textrm{cm}^2$ㆍsec$^{-1}$ at 130$0^{\circ}C$, respectively.

• 대한화학회지
• /
• 제8권2호
• /
• pp.57-61
• /
• 1964

It was verified at Part Ⅰ of this investigation that there is a minimum wettability between molten iron and graphite, which was preliminarily coated with magnesium, and thus the spheroidization of graphite might have resulted from the lack of wettability between magnesium-adsorbed graphite and iron matrix. Being continued from the last work, the wettability between pure iron and graphite, coated with the various thickness of cerium, are measured at melting point of pure iron in vacuum and 200 mmHg argon gas atmosphere. The result indicates the presence of a minimum wettability at a critical thickness of cerium film as was proved in the case of magnesium. The experimental analysis shows that, the minimum wettability could be attributed entirely to a minimum work of adhesion between liquid iron and graphite at a critical concentration of cerium in the iron-graphite interface.

• 한국분말재료학회지
• /
• 제28권6호
• /
• pp.518-526
• /
• 2021

This review summarizes the recent progress in iron-oxide-based heat generators. Cancer treatment using magnetic nanoparticles as a heat generator, termed magnetic fluid hyperthermia, is a promising noninvasive approach that has gained significant interest. Most previous studies on improving the hyperthermia effect have focused on the construction of dopant-containing iron oxides. However, their applications in a clinical application can be limited due to extra dopants, and pure iron oxide is the only inorganic material approved by the Food and Drug Administration (FDA). Several factors that influence the heat generation capability of iron-oxide-based nanoparticles are summarized by reviewing recent studies on hyperthermia agents. Thus, our paper will provide the guideline for developing pure iron oxide-based heat generators with high heat dissipation capabilities.

• 한국해양공학회지
• /
• 제17권5호
• /
• pp.76-81
• /
• 2003

Friction welding of GCD45 spheroidal graphite cast iron and 2024 aluminum alloy has been studied, especially in terms of the joint faces and strength of friction welding. For appropriate results of the friction welding of GCD45 graphite cast iron and 2024 aluminum alloy, an insert of A1050 pure aluminum metal was used. The joint strength of the A1050 pure aluminum insert approached the maximum strength of 165.7Mpa, compared to 128MPa for the joint between GCD45 graphite cast iron and A1050 pure aluminum without the insert metal. Maximum strength, 165.7Mpa, was possible for the following optimum conditions: 20MPa for the friction pressure, P1, 60MPa for the upsetting pressure, P2, 1 second for the friction time, t1, 3000rpm for the rotation, N, and 0.3 seconds for the brake time, tB.

• 보존과학연구
• /
• 통권14호
• /
• pp.1-34
• /
• 1993

1. Metallurgical Properties of Iron artifacts excavated from Yangju-Mountain fortress were studied for the scientific conservation and metallurgical history of ancient Iron artifacts.2. Iron artifacts form Yangju-Mountain fortress were found to be the products of having well-established Carburizing and remelting technique in that period.3. These artifacts seem to be manufactured from very pure ores, because very pure ferrite structure and low impurity.4. Especially evidence of very suitable carburizing technic well-established and usealloying method of Fe-C system on purpose were found.5. Cast iron artifacts were found to be eutectic composition (4.31%) having lowestmelting point in Fe-C system.