• 제목/요약/키워드: high corrosion resistance

검색결과 1,065건 처리시간 0.023초

Surface hardening and enhancement of Corrosion Resistance of AISI 310S Austenitic Stainless Steel by Low Temperature Plasma Nitrocarburizing treatment.

  • Lee, Insup
    • 한국표면공학회:학술대회논문집
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    • 한국표면공학회 2012년도 추계총회 및 학술대회 논문집
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    • pp.175-177
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    • 2012
  • A corrosion resistance and hard nitrocarburized layer was distinctly formed on 310 austenitic stainless steel substrate by DC plasma nitrocarburizing. Basically, 310L austenitic stainless steel has high chromium and nickel content which is applicable for high temperature applications. In this experiment, plasma nitrocarburizing was performed in a D.C. pulsed plasma ion nitriding system at different temperatures in $H_2-N_2-CH_4$ gas mixtures. After the experiment structural phases, micro-hardness and corrosion resistance were investigated by the optical microscopy, X-ray diffraction, scanning electron microscopy, micro-hardness testing and Potentiodynamic polarization tests. The hardness of the samples was measured by using a Vickers micro hardness tester with the load of 100 g. XRD indicated a single expanded austenite phase was formed at all treatment temperatures. Such a nitrogen and carbon supersaturated layer is precipitation free and possesses a high hardness and good corrosion resistance.

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Improvement of the Corrosion Resistance of PVD Hard Coating/Substrate Systems - Recent Developments -

  • Jehn, Hermann A.;Kang, Sung-Goon
    • 한국표면공학회지
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    • 제32권3호
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    • pp.472-483
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    • 1999
  • Hard coatings playa continuously increasing role in the field of tribology as well as for decorative applications. In both areas they are often also exposed to corrosive media. While especially hard nitride coatings show a high corrosion resistance for themselves, hard $coating_strate systems may suffer from a severe corrosion attack due to the defects in the coating structure (pores, pinholes) resulting from the PVD-typical film morphology. While a huge number of investigations cover the tribological properties, only limited studies deal with the corrosion behavjour of coating substrate systems and attempts are made to improve their corrosion resistance. The present paper shortly describes the corrosion mechanisms and repots characteristic examples of the system behaviour. Special emphasis is laid on recent investigations to improve the corrosion resistance by alloying, interlayers or multilayered coating structures.es.

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가스 질화를 통한 316L스테인리스강의 내식성 개선 (Improvement of Corrosion Resistance of 316L Stainless Steel by Gas Nitriding)

  • 조현빈;박세림;김지수;이정훈
    • 전기화학회지
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    • 제27권1호
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    • pp.8-14
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    • 2024
  • 오스테나이트계 스테인리스강은 내식성 및 성형성이 양호하여 다양한 분야에 적용되며, 구리계의 합금을 용가재로 하는 브레이징을 통하여 다양한 형상의 제품으로 가공되어 활용되고 있다. 이때, 구리 기반의 용가재와 스테인리스강의 계면에서 갈바닉 셀을 형성하여 부식을 촉진할 수 있으며, 확산을 통해 스테인리스강에 고용 시 형성되는 구리 과다 영역(Cu-rich region)은 공식 발생의 기점이 되어 내식성을 저하시킨다. 본 연구에서는 브레이징이 적용된 스테인리스강의 내식성을 개선하고자, AISI 316L 스테인리스강에 암모니아 가스를 이용한 질화처리를 적용하였다. 질화처리한 시편은 처리 온도가 증가함에 따라 두께가 증가하고 표면 경도가 높아졌다. 동전위분극시험을 통해 내식성을 평가한 결과 질화층 내 고용된 질소의 용출 및 부동태 거동으로 모재대비 내식성이 개선되었지만 처리온도가 높아 크롬질화물(CrN) 분율이 증가하는 경우 내식성이 감소하였다.

분극저항에 의한 온라인 부식속도 측정 시스템에 관한 연구 (Study on an On-line Measurement System of Corrosion Rate by Linear Polarization Resistance)

  • 문전수;이재근;이재봉;박필양
    • Corrosion Science and Technology
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    • 제11권4호
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    • pp.135-140
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    • 2012
  • The linear polarization resistance method is one of the widely used techniques for the corrosion rate monitoring in the water circulating systems of plants. The measurement is simple and rapid, so that a continuous on-line monitoring is possible without any shutdown of plants. A 2-electrode polarization corrosion rate measurement system was installed in a laboratory using a data acquisition board and PC. The signal processing parameters were optimized for the accurate corrosion rate measurement, and the polarization resistance was compensated with the solution resistance measured by the high frequency sine wave signal of an output channel. The precision of corrosion rate data was greatly improved by removing the initial noise signals on measuring the polarization resistance.

Evaluation on the Corrosion Resistance of Three Types of Galvanizing Steels in 1% H2SO4 Solution

  • Moon, Kyung-Man;Lee, Sung-Yul;Lee, Myeong-Hoon;Jeong, Jae-Hyun;Baek, Tae-Sil
    • 한국표면공학회지
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    • 제49권3호
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    • pp.245-251
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    • 2016
  • Galvanizing method has been extensively used to the numerous constructional steels such as a guard rail of high way, various types of structural steel for ship building and various types of steels for the industrial fields etc.. However, the galvanized structures would be inevitably corroded rapidly with increasing exposed time because an acid rain due to environmental contamination has been much dropped more and more. Therefore, it has been made an effort to improve the corrosion resistance of the galvanizing film through various methods. In this study, comparison evaluation on the corrosion resistance of three types of the samples, that is, the hot dip galvanizing with pure zinc(GI), the hot dip galvanizing of alloy bath with zinc and aluminum(GL) and the pure zinc galvanizing steel immersed again to chromate treatment bath(Chro.)were investigated using electrochemical methods in 1% $H_2SO_4$ solution. The Chro. and GI samples exhibited the highest and lowest corrosion resistance respectively in 1% $H_2SO_4$ solution, however, the GI sample revealed the highest impedance at 0.01 Hz due to its high resistance polarization caused by corrosion products deposited on the surface, while Chro. sample exhibited the lowest impedance at 0.01 Hz because of little corrosion products on the surface. Consequently, it is suggested that the chromate treated steel has a better corrosion resistance in acid environment compared to pure galvanizing(GI) or galvalume(GL) steels.

Enhancement of Surface Hardness and Corrosion Resistance of AISI 310 Austenitic Stainless Steel by Low Temperature Plasma Carburizing Treatment

  • Lee, Insup
    • 한국표면공학회지
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    • 제50권4호
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    • pp.272-276
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    • 2017
  • The response of AISI 310 type austenitic stainless steel to the novel low temperature plasma carburizing process has been investigated in this work. This grade of stainless steel shows better corrosion resistance and high temperature oxidation resistance due to its high chromium and nickel content. In this experiment, plasma carburizing was performed on AISI 310 stainless steel in a D.C. pulsed plasma ion nitriding system at different temperatures in $H_2-Ar-CH_4$ gas mixtures. The working pressure was 4 Torr (533Pa approx.) and the applied voltage was 600 V during the plasma carburizing treatment. The hardness of the samples was measured by using a Vickers micro hardness tester with the load of 100 g. The phase of carburized layer formed on the surface was confirmed by X-ray diffraction. The resultant carburized layer was found to be precipitation free and resulted in significantly improved hardness and corrosion resistance.

NEW RESULTS CONCERNING THE INFLUENCE OF HEAT TINGS DURING WELDING ON THE CORROSION RESISTANCE OF STAINLESS STEELS

  • Wohlfahrt, H.;Pries, H.;Saggau, R.
    • 대한용접접합학회:학술대회논문집
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    • 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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    • pp.29-37
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    • 2002
  • High alloyed stainless steels stand out for a high corrosion resistance due to a protective passive layer which is formed when the content of chromium exceeds 13%. When welding these steels, heat tints arise in the area of the weldment. They may occur from flint yellow to intensive blue in the spectrum depending on the applied welding process and the quality of the backing gas used. Due to their structures, they partly drastically reduce the corrosion resistance of stainless steels so that they may lead to damages of the technical application of welded components. In the following the pitting resistance by different backing gases and the chemical composition of the stainless steel itself are described.

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인발가공된 스테인리스강선의 표면특성에 미치는 Ni코팅의 영향 (Effects of Ni Coating on the Surface Characteristics of Drawed Stainless Steel Wire)

  • 최한철
    • 한국표면공학회지
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    • 제36권5호
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    • pp.398-405
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    • 2003
  • The stainless steel wire requires good corrosion resistance and mechanical properties, such as drawing ability, combined with a high resistance to corrosion. For increasing drawing ability of stainless steel, Ni coating methods have been used in this study. However, there is no information on the electrochemical corrosion behavior of drawed wires after Ni coating. To investigate corrosion resistance and mechanical property of drawed wire, the characteristics of Ni coated wires have been determined by tensile strength tester, hardness tester, field emission scanning microscope, energy dispersive x-ray analysis and potentiodynamic method in 0.1 M HCl. The drawed stainless steel wires showed the strain-induced martensitic structure, whereas non-drawed stainless steel wire showed annealing twin in the matrix of austenitic structure. The hardness and tensile strength of drawed stainless steel wire were higer than that of non-drawed stainless steel wire. Electrochemical measurements showed that, in the case of drawed stainless steel o ire after Ni coating, the corrosion resistance and pitting potential increased compared with non-coated and drawed stainless steel wire due to decrease in the surface roughness.

A study on zinc phosphate conversion coatings on Mg alloys

  • Phuong, Nguyen Van;Lee, Kyuhwan;Chang, Doyon;Kim, Man;Lee, Sangyeoul;Moon, Sungmo
    • 한국표면공학회:학술대회논문집
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    • 한국표면공학회 2012년도 추계총회 및 학술대회 논문집
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    • pp.17-17
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    • 2012
  • Magnesium alloys exhibit many attractive properties such as low density, high strength/weight ratio, high thermal conductivity, very good electromagnetic features and good recyclability. However, most commercial magnesium alloys require protective coatings because of their poor corrosion resistance. Attempts have been made to improve the corrosion resistance of the Mg alloys by surface treatments, such as chemical conversion coatings, anodizing, plating and metal coatings, are commonly applied to magnesium alloys in order to increase the corrosion resistance. Among them, chemical conversion coatings are regarded as one of the most effective and cheapest ways to prevent corrosion resistance. In this study, zinc phosphate conversion coatings on various Mg alloys have been developed by selecting proper phosphating bath composition and concentration and by optimizing phosphating time, temperature. Morphology, coatings composition, corrosion resistance, adhesion and its formation and growth mechanism of the zinc phosphate conversion coatings were studied. Results have shown some attractive properties such as simplicity in operation, significantly increased corrosion protective property. However, adhesions between coatings and substrate and also between coatings and paint are still not satisfied. Resolving the problems and understanding the mechanism of phosphating process are targets of our study.

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용융알루미늄 도금 강판 상에 스퍼터링법으로 형성된 마그네슘 코팅막에 의한 내식성 향상 (Improvement of Corrosion Resistance by Mg Films Deposited on Hot Dip Aluminized Steel using a Sputtering Method)

  • 박재혁;김순호;정재인;양지훈;이경황;이명훈
    • 한국표면공학회지
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    • 제51권4호
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    • pp.224-230
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    • 2018
  • In this study, Mg films were prepared on hot dip aluminized steel (HDA) by using a sputtering method as a high corrosion resistance coating. The corrosion resistance of the Mg films was improved by controlling the morphology and the crystal structure of films by adjusting the Ar gas pressure during the coating process. Anodic polarization measurement results confirm that the corrosion resistance of the Mg films was affected by surface morphology and crystal structure. The corrosion resistance of the Mg coated HDA specimen increased with decreasing crystal size of the Mg coating and it was also improved by forming a film with denser morphology. The crystal structure oriented at Mg(101) plane showed the best corrosion resistance among crystal planes of the Mg metals, which is attributed to its relatively low surface energy. Neutral salt spray test confirmed that corrosion resistance of HDA can be greatly improved by Mg coating, which is superior to that of HDG (hot dip galvanized steel). The reason for the improvement of the corrosion resistance of Mg films on hot dip aluminized steel was due to the barrier effect by the Mg corrosion products formed by the corrosion of the Mg coating layer.