• 제목/요약/키워드: Ni-P/Cr

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Effects of Film Formation Conditions on the Chemical Composition and the Semiconducting Properties of the Passive Film on Alloy 690

  • Jang, HeeJin;Kwon, HyukSang
    • Corrosion Science and Technology
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    • 제5권4호
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    • pp.141-148
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    • 2006
  • The chemical composition and the semiconducting properties of the passive films formed on Alloy 690 in various film formation conditions were investigated by XPS, photocurrent measurement, and Mott-Schottky analysis. The XPS and photocurrent spectra showed that the passive films formed on Alloy 690 in pH 8.5 buffer solution at ambient temperature, in air at $400^{\circ}C$, and in PWR condition comprise $Cr_2O_3$, $Cr(OH)_3$, ${\gamma}-Fe_2O_3$, NiO, and $Ni(OH)_2$. The thermally grown oxide in air and the passive film formed at high potential (0.3 $V_{SCE}$) in pH 8.5 buffer solution were highly Cr-enriched, whereas the films formed in PWR condition and that formed at low potential (-0.3 $V_{SCE}$) in pH 8.5 buffer solution showed relatively high Ni content and low Cr content. The Mott-Schottky plots exhibited n-type semiconductivity, inferring that the semiconducting properties of the passive films formed on Alloy 690 in various film formation conditions are dominated by Cr-substituted ${\gamma}-Fe_2O_3$. The donor density, i.e., concentration of oxygen vacancy, was measured to be $1.2{\times}10^{21}{\sim}4.6{\times}10^{21}cm^{-3}$ and lowered with increase in the Cr content in the passive film.

동위원소희석 유도결합플라스마질량분석법에 의한 저 합금강 표준시료중의 Ni, Cr, Mo의 분석 (Determination of Ni, Cr, Mo in Low Alloy Steel Reference Materials by Isotope Dilution Inductively Coupled Plasma Mass Spectrometry)

  • 서정기;우진춘;민형식;임명철
    • 분석과학
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    • 제16권1호
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    • pp.82-89
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    • 2003
  • Isotope dilution mass spectrometry (IDMS) was applied to the determination of Ni, Cr, Mo in low alloy steel reference materials. The Mo isotope ratio measurement was performed by dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP/MS) using ammonia as a reaction cell gas. In the case of Ni and Cr measurement, all data were obtained at medium resolution mode (m/${\Delta}m=3000$) of double focusing sector field high resolution inductively coupled plasma mass spectrometry (HR-ICP/MS). For the method validation of the technique was assessed using the certified reference materials such as NIST SRM 361, NIST SRM 362, NIST SRM 363, NIST SRM 364, NIST SRM 36b. This method was applied to the determination of Ni, Cr and Mo in low alloy steel sample (CCQM-P25) provided by NMIJ for international comparison study.

아말감과 이종(異種)금속의 거리에 따른 부식에 대한 고찰 (A Study on Corrosion according to Distance between Amalgam and Dissimilar Metals)

  • 김주원;정은경
    • 치위생과학회지
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    • 제4권3호
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    • pp.103-109
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    • 2004
  • 본 실험은 제조회사 매뉴얼과 통법에 의해서 Amalgam 합금, Ni-Cr alloy의 Crown용 Verabond, Denture용 Talladium $^{TM}alloy$로 각각 24개의 총 72의 시편을 하악 제1대구치근 원심 치관 폭경과 임상에서의 MOD cavity를 고려하여 제작하였고 인공 타액 80ml를 담은 200ml 용 비이커에 시편을 넣어 0mm, 7mm, 40mm 거리에서 7일 후 갈바닉 부식을 측정하였다. 유리금속은 유도 플라즈마 방출 분광기(Inductively Coupled Plasma - Atomic Emission Spectrometer(ICP-AES, JY-50P, VG Elemental Co. France)로 전해액내의 Cu, Ag, Ni, Cr, Sn, Zn, Hg를 정량 분석했으며 그 결과 다음과 같은 결론을 얻었다. 첫째, Cu, Sn, Ag, Hg, Zn은 아말감이 금 합금과 접촉했을 때가 크라운용 Ni-Cr alloy와 덴쳐용 Talladium alloy 보다 아주 많이 유리 했으며 금 합금이 구강조직과 생체 적합성이 가장 좋다지만 아말감과 함께 있을 때 가장 불리 했슴을 알 수 있었다. 둘째, 아말감이 금 합금과 접촉했을 때, 금 합금의 조성에서 Ni, Cr 같은 중금속이 함유되지 않았기 때문인지 전혀 유리되지 않았으나 Sn은 조성에는 없었지만 $227.1{\pm}18.0035{\mu}g/cm^2$나 유리 되었고 Hg도 유리되었는데 이는 아말감 자체의 유리 물질임을 추측할 수 있었다. 셋째, 아말감 합금과 금 합금 사이에서의 0mm, 7mm, 40mm 거리에서는 Cu, Ag는 유의성이 있었으며 Hg는 유의성이 없었다. 이는 금합금은 절대 아말감과 같이 사용해서 안되며 이종 보철물 사이의 거리에 관계없이 사용을 금해야 하는 것으로 사료된다. 넷째, 아말감합금이 Crown용 Ni-Cr 합금과 접촉했을 때 아말감의 Ag이 유리 되지 않았으며 Zn, Ni, Sn, Hg, Cu의 순으로 유리되었다. 0mm, 7mm, 40mm 거리에 따라서 유의성이 있었다. Hg는 유리 되지 않았지만 중금속인 Ni, Cr은 유리되었고 반대 악궁이나 거리가 떨어져 있으면 접촉보다 Hg의 유리가 적었다. 다섯째, 아말감합금이 Denture용 Talladium alloy 합금과 접촉했을 때 0mm, 7mm, 40mm 거리에서도 유의성이 있었다. 0mm, 7mm, 40mm 거리에 따라서 유의성이 있었다. Hg는 유리 되지 않았지만 중금속인 Ni, Cr은 유리되었고 반대 악궁이나 거리가 떨어져 있으면 접촉보다 Hg의 유리가 적었다. 여섯째, 인공 타액에서 접촉 시 Amalgam alloy와 Gold, Verabond, Talladium alloy의 Cu, Sn, Ag, Hg, Zn, Ni, Cr의 ICPES 검사 결과 Cu, Hg가 유의성을 있었다. 일곱째, 인공타액에서 아말감합금과 두 비귀금속인 Ni-Cr alloy(crown용), Denture용 Talladium alloy가 접촉한 경우 거리에 따른 Hg, Ni, Cr의 유리 부산물에서 유의성을 확인했다.

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전북지방 치과기공실 공기중 및 치과기공사의 뇨중중금속 함량에 관한 연구 (Study on Heavy Metal Contents in Air of Den Tal Laboratories and Urine of Dental Laboratory Technicians in CHONBUK Area)

  • 이정오;이종섭;유인수
    • 한국환경보건학회지
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    • 제16권2호
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    • pp.97-103
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    • 1990
  • For this study, I used the urine of 100 dental laboratroy technicians and 24 students in Chonbuk region. The purposes of this study were to investigate concentrations of cadmium (Cd), nickel (Ni) and chromium (Cr) in the air of dental laboratories. The results were as follows: 1. The concentrations of Cd is 0.0115mg/m$^{3}$ in the porcelain part, 0.0090mg/m$^{3}$ in the polishing part, that of Ni is 0.2864mg/m$^{3}$ in the porcelain part, 0.3188mg/m$^{3}$ in the polishing part, that of Cr is 0.0448mg/m$^{3}$ in the porcelain part, 0.1032mg/m$^{3}$ in the polishing part. 2. The concentrations of Cd, Ni and Cr in the technicians urine are 3.06 $\mu$g/l, 44.55 $\mu$g/l and 14.58 $\mu$g/l. Those of students, urine as the control group are 1.93 $\mu$g/l, 19.05 $\mu$g/l and 7.48 $\mu$g/l. There is significant difference between experimental group and control group (P < 0.01). 3. Watching for age and working place, 31-40 years age group reveals the highest group in the concentrations of Cd. Over 41 year age group represents the highest group in the concentrations of Ni and Cr (P < 0.01) The concentration of Cd turns up the highest in the partial part and that of Ni and Cr appears the highest in the polishing part (P < 0.01). Looking into working age, over 7 year group is the highest group in the concentrations of all investigated (P < 0.05).

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HVOF 용사법에 의해 제조된 WC계 합금 코팅층의 방식특성(II) - 알칼리 용액에서의 분극특성 - (Anti-Corrosion Characteristics of WC-based Alloy Coatings Fabricated by HVOF Process - Polarization Characteristics in Alkaline Solution -)

  • 김태용;김영식;김재동
    • 동력기계공학회지
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    • 제18권6호
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    • pp.40-44
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    • 2014
  • The purpose of this paper is to investigate polarization characteristics of WC-based alloy coatings in alkaline solution. The coatings were fabricated with WC-CrC-Ni, WC-Co-Cr and WC-Co composite powders by HVOF process. Corrosion tests of coatings and substrate were carried out using potentiostat/galvanostat at solution with pH 8 and pH 13. Corrosion potential(Ecorr) and corrosion current density(Icorr) could be studied from polarization curve, and corrosion behavior was analyzed by SEM and EDS. WC-Co-Cr coating and WC-CrC-Ni coating showed more favorable anti-corrosion characteristics than WC-Co coating and substrate at solution with pH 8 and pH 13.

HVOF 용사법에 의해 제조된 WC계 합금 코팅층의 방식특성(I) - 산성용액에서의 분극특성 - (Anti-Corrosion Characteristics of WC-based Alloy Coatings Fabricated by HVOF Process - Polarization Characteristics in Acid Solution -)

  • 김태용;김영식
    • 동력기계공학회지
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    • 제18권4호
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    • pp.72-77
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    • 2014
  • The aim of this study to investigate polarization characteristics of WC-based alloy coatings fabricated by high velocity oxygen fuel(HVOF) process. The coatings were fabricated by HVOF process with WC-CrC-Ni, WC-Co-Cr, WC-Co composite powders. Corrosion tests were carried out using potentiostat/galvanostat at solution with pH 2 and pH 6. Corrosion potential(Ecorr) and corrosion current density(Icorr) could be analyzed from polarization curve. WC-Co-Cr coating showed more incorrodible characteristics than other coatings at solution pH 2. WC-CrC-Ni coating was more favorable anti-corrosion characteristics than other coatings at solution with pH 6.

Ni-Cr-Mo-V강의 전기화학적 방법에 의한 내식성 평가 (Evaluation of corrosion resistance by electrochemical method for Ni-Cr-Mo-V steel)

  • 권재도;문윤배
    • 대한기계학회논문집A
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    • 제21권9호
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    • pp.1422-1431
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    • 1997
  • When the structures are exposed to their own an application for a long period, a number of variables such as strength properties and corrosion resistance, so on are expected to change. In the present investigation the corrosion behavior and resistance for the original and degraded materials of Ni-Cr-Mo-V steel were evaluated under the conditions of pH 3, 6, 9 and 12 in a distilled water environment. The electrochemical polarization technique was employed in this investigation. Based upon the experimental results obtained, the following conclusions were drawn. A severe and uniform corrosion was observed for both original and degraded materials under the condition of pH 3. At pH 6 and pH 9, these materials showed the degradation by a pitting corrosion. The materials under pH 12 environment were degraded by a uniform corrosion. The corrosion rate per year were the highest in the pH 3 environment, followed by pH 12, pH 6 and pH 9 environment in order. The corrosion resistance was decreased from the original material, slow cooled material (10.deg. C/hr) and step cooled material in order.

압력용기용 Ni-Mo-Cr계 고강도 저합금강의 P, Mn 함량에 따른 템퍼 취화거동 및 입계편석거동 평가 (Evaluation of Temper Embrittlement Effect and Segregation Behaviors on Ni-Mo-Cr High Strength Low Alloy RPV Steels with Changing P and Mn Contents)

  • 박상규;김민철;이봉상;위당문
    • 대한금속재료학회지
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    • 제48권2호
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    • pp.122-132
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    • 2010
  • Higher strength and fracture toughness of reactor pressure vessel steels can be obtained by changing the material specification from that of Mn-Mo-Ni low alloy steel (SA508 Gr.3) to Ni-Mo-Cr low alloy steel (SA508 Gr.4N). However, the operation temperature of the reactor pressure vessel is more than $300^{\circ}C$ and the reactor operates for over 40 years. Therefore, we need to have phase stability in the high temperature range in order to apply the SA508 Gr.4N low alloy steel for a reactor pressure vessel. It is very important to evaluate the temper embrittlement phenomena of SA508 Gr.4N for an RPV application. In this study, we have performed a Charpy impact test and tensile test of SA508 Gr.4N low alloy steel with changing impurity element contents such as Mn and P. And also, the mechanical properties of these low alloy steels after longterm heat treatment ($450^{\circ}C$, 2000hr) are evaluated. Further, evaluation of the temper embrittlement by fracture analysis was carried out. Temper embrittlement occurs in KL4-Ref and KL4-P, which show a decrease of the elongation and a shifting of the transition curve toward high temperature. The reason for the temper embrittlement is the grain boundary segregation of the impurity element P and the alloying element Ni. However, KL4-Ref shows temper embrittlement phenomena despite the same contents of P and Ni compared with SC-KL4. This result may be caused by the Mn contents. In addition, the behavior of embrittlement is not largely affected by the formation of $M_3P$ phosphide or the coarsening of Cr carbides.

Ni-Cr-Fe 및 Ni-Fe-Cr-Mo계 합금의 용접부 균열특성에 관한 연구 Part I : 용착금속의 응고균열 (A Study on the Cracking Behavior in the Welds of Ni-Cr-Fe and Ni-Fe-Cr-Mo Alloys Part I : Solidification Cracking in the Fusion Zone)

  • 김희봉;이창희
    • Journal of Welding and Joining
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    • 제15권4호
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    • pp.78-89
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    • 1997
  • This study has evaluated the weld metal solidification cracking behavior of several Ni base superalloys (Incoloy 825, Inconel 718 and Inconel 600). Austenitic stainless steels(304, 310S) were also included for comparison. In addition, a possible mechanism of solidification cracking in the fusion zone was suggested based on the extensive microstructural examinations with SEM, EDAX, TEM, SADP and AEM. The solidification cracking resistance of Ni base superalloys was found to be far inferior to that of austenitic stainless steels. The solidification cracking of Incoloy 825 and Inconel 718 was believel to be closely related with the Laves-austenite (Ti rich in 825 and Nb rich in 718) and MC-austenite eutectic phases formed along the grain boundaries during solidification. Cracking in Inconel 600 was always found along the grain boundaries which were enriched with Ti and P. Further, solidifidcation cracking resistance was dependent not only upon the type of love melting phases but also on the amount of the phases along the solidification grain boundaries.

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서울시 가로수의 연륜층 및 식재주변 토양의 증금속 농도와 연륜 생장 (Heavy Metal Concentrations in Tree Ring Layer and Soil and Tree Ring Growth of Roadside Trees in Seoul)

  • 유재윤;손요환
    • 한국환경농학회지
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    • 제22권2호
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    • pp.118-123
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    • 2003
  • 본 연구는 서울 도심에 위치한 가로수 중에서 수령이 30년 이상 된 양버즘나무(Platanus occidentalis L.)와 은행나무(Ginkgo biloba L.)를 대상으로 토양 및 가로수의 연륜층별로 중금속 농도를 분석하여 이들 중금속이 가로수의 연륜 생장에 미치는 영향 정도를 비교 검토하였다. 가로수가 식재되어 있는 토양의 pH는 $6.62{\sim}8.01$이었으며, 중금속 평균농도는 Cr 0.63, Zn 109.03, Pb 26.49, Ni 1.98, Cu 44.98 mg/kg으로써 이 중 Zn, Pb, Cu의 농도는 일반 산림토양보다 높은 것으로 나타났다. 특히 금속 및 철물을 취급하는 상가가 밀집해 있고 차량통행이 많은 청계 2가 지역의 중금속 농토가 가장 높게 나타났다. 가로수의 연륜폭을 1979년부터 2000년까지 측정하여 회귀식으로 나타낸 결과, 두 수종 모두 감소하는 경향을 보였다. 또한, 토양 내 Cr, Pb, Cu의 농도는 양버즘나무의 최근 5년간 연륜층 내 Cr, Pb, Cu 농도와 양의 상관관계를 보였으며, 토양 내 Ni 농도는 은행나무의 연륜층 내 Ni 농도와 양의 상관관계를 보였다. 양버즘나무의 5년 단위 연륜층별 Cr 농도와 은행나무의 5년 단위 연륜층별 Ni, Cu 농도는 각각 연륜생장에 음의 상관관계를 나타냈다. 한편 서울지역의 연평균 기온, 강수량, 강수일수와 연륜폭의 연도별 변화 경향은 유사하였으나 통계적으로 유의성은 인정되지 않았다.