• 제목/요약/키워드: NiCr alloy

검색결과 449건 처리시간 0.035초

$\textrm{Fe}_{80-x}\textrm{P}_{10}\textrm{C}_{6}\textrm{B}_{4}\textrm{M}_{x}$(M=Transition Metal) 비정질합금의 열적안정성 (Thermal Stability of $\textrm{Fe}_{80-x}\textrm{P}_{10}\textrm{C}_{6}\textrm{B}_{4}\textrm{M}_{x}$(M=Transition Metal) Amorphous Alloys)

  • 국진선;전우용;진영철;김상협
    • 한국재료학회지
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    • 제7권3호
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    • pp.218-223
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    • 1997
  • 과냉각액체구역(${\Delta}T_{x}=T_{x}-T_{g}$)을 갖는 $Fe_{80}P_{10}C_{6}B_{4}$ 조성에 천이금속(Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Co, Ni, Pd, Pt및 Cu)를 첨가하여 이들 원소가 유리화온도($T_{g}$), 결정화온도($T_{x}$) 및 과냉액체구역 (${\Delta}T_{x}$)에 미치는 영향에 \ulcorner여 조사하였다. $Fe_{80}P_{10}C_{6}B_{4}$ 합금의 ${\Delta}T_{x}$ 값은 27K였으나 이 합금에 Hf, Ta 및 Mo을 각각 4at%첨가하면 그 값이 40k 이상으로 증가하였다. 이같은 ${\Delta}T_{x}$ 값의 증가는 유리화온도($T_{g}$의 상승보다 결정화온도($T_{x}$)의 상승폭이 크기 때문이다. $T_{g}$$T_{x}$는 외각전자밀도(e/a)가 약 7.38에서 7.05로 감소할수록 상승하였다. e/a의 감소는 천이금속과 다른 구성원소(반금속)사이의 상호결합상태를 의미한다. 즉 $T_{g}$$T_{x}$의 상승은 강한 상호결합력에 기인하는 것으로 사료된다.

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도재용착용 Non beryllium 합금의 degassing과 opaque의 소성술식에 따른 결합강도 분석 (Shear bond strength analysis of non beryllium PFM metal with degassing and opaque firing techniques)

  • 임중재;이상혁
    • 한국산학기술학회논문지
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    • 제16권7호
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    • pp.4357-4363
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    • 2015
  • 본 연구는 베릴륨 함유하지 않은 Ni-Cr계 도재용 금속에 전용도재를 도포, 소성된 시편을 3점 굴곡 시험으로 결합강도를 측정하고, SAM/EDS로 표면성분관찰 실험한 AVOVA와 Tukey HSAD 사후검정을 실시한 결과는 다음과 같은 결론을 얻었다. 첫째. 모든 군에서 ISO 9693의 치과용 금속-도재 시편의 최소 결합강도의 최소치인 25 MPa의 전단결합강도를 상위하며 안정적인 결과값을 나타냈다. 둘째. 결합 강도는 대조군 V1은 $32.37{\pm}1.91MPa$으로 나타났고, 실험군 V2 $38.25{\pm}1.38MPa$, 실험군 V3 $46.43{\pm}2.14MPa$, 그리고 실험군 V4 $47.21{\pm}1.72MPa$, 순으로 나타났으며 통계적으로 유의한 차이를 보였다. 사후 검정 (Tukey's HSD test) 결과, 결합강도 실험결과 실험군 V4는, 대조군 V1보다 높게 나타났다. 셋째. 금속-도재의 결합에서 산화처리를 시행한 군보다 시행하지 않고 불투명 도재를 도포하고 소성한 군이 높게 나타났으며, paste불투명 도재보다 분말 불투명도재의 사용에 따른 결합강도가 더 높게 나타났다. 넷째. 실험군 V4는 금속과 도재의 결합강도 비교에서 가장 높게 나타났다.

수종의 post와 IPS-Empress Ingot 두께가 전부 도재 수복물 최종색조에 미치는 영향 (INFLUENCE OF SEVERAL POSTS AND IPS-EMPRESS INGOT THICKNESS ON THE FINAL SHADE OF ALL-CERAMIC CROWNS)

  • 복원미;최근배;박찬운;안승근
    • 대한치과보철학회지
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    • 제42권5호
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    • pp.514-523
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    • 2004
  • Statement of problem: All-ceramic restorations have been advocated for superior esthetics. Various post and core systems have been used to improve the strength of damaged teeth, but it is unclear whether they affect the final shade of finished all-ceramic restorations. Purpose: The influence of different types of post and core systems on light transmission through all-ceramic crowns was assessed by spectrophotometric analysis. Also the masking effect of different thickness of ceramic ingot was evaluated. Material and Methods : Forty-five sample disks (15mm in diameter) at several thickness(1.0, 1.5, 2.0mm) and value(shade 100, 200, 300) were made in heat pressed ceramic(IPS-Empress). Background specimens simulating gold-alloy cast posts(Type III casting gold alloy), metal posts(Ni-Cr casting alloy) and ceramic posts(CosmoPost) were fabrica-ted. Resin composite(Z250, A3 shade) was used as a tooth substrate reference. For each combination, the change in color was measured with a spectrophotometer. Readings were performed for 2 conditions (1) ability of ceramic to mask the core in relation to its thickness(1.0, 1.5, or 2.0mm) ; (2) influence of post and core types on the final color of the ceramic. Data were recorded according to the CIE $L^*a^*b^*$ systems and color difference($\Delta$E) was calculated. Results: 100 shade ingot: when ceramic thickness was 1.0mm, $\Delta$E value for ceramic post larger than 1 but $\Delta$E value for metal and gold post was larger than 2. For ceramic thickness of 1.5mm, only $\Delta$E value for metal was larger than 2, and the other samples' $\Delta$E value was smaller than 2. For ceramic thickness of 2.0mm, $\Delta$E values for all specimens was smaller than 2. 200 shade ingot: when ceramic thickness was 1.0mm, $\Delta$E value for ceramic post was smaller than 1 but $\Delta$E value for metal and gold post was larger than 2. For ceramic thickness of 1.5 mm, only the $\Delta$E value for metal was larger than 2, and the other samples' $\Delta$E value was smaller than 2. For ceramic thickness of 2.0mm, $\Delta$E values for all specimens was smaller than 1. 300 shade ingot: when ceramic thickness was 1.0mm, only $\Delta$E value for metal was larger than 2 and the other samples' $\Delta$E value was smaller than 2. For ceramic thickness of 1.5mm, $\Delta$E values for all specimens was smaller than 1. For ceramic thickness of 2.0mm, $\Delta$E values for all specimens was smaller than 1. Conclusion: The final esthetic result of the IPS-Empress glass-ceramic restoration was not affected by the presence of different core materials when the thickness was more than 2.0 mm. When ceramic thickness decreases to 1.5mm, it is advised to take the substrate aspects into consideration. If the ceramic thickness is less than 1.0mm, using the tooth color matched substrate is strongly recommended.

염산(鹽酸)에 의한 CMSX-4 초내열합금(超耐熱合金)의 침출(浸出) (Leaching of CMSX-4 Superalloy in Hydrochloric Acid Solutions)

  • 김민석;이재천;김은영;유영수
    • 자원리싸이클링
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    • 제19권5호
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    • pp.25-30
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    • 2010
  • CMSX-4 초내열합금의 순환활용을 위한 습식제련기술 개발의 일환으로 영신에서의 니켈, 코벨트, 크롬, 알루미늄 등 주요 구성 금속성분들의 침출 특성을 조사하였다. 염산농도에 따른 합금시료 내 주요 금속성분들의 침출율은 염산농도가 높아짐에 따라 증가하였으나, 3 M 이상에서는 둔화되었다 염산농도 4 M, 고액비 10 g/L, 침출시간 60 분 조건에서 침출온도가 높아짐에 따라 침출율은 급격히 증가하였으며, $90^{\circ}C$에서 니켈 93.2%, 알루미늄 89.9%, 코발트 80.4%, 크롬 79.1%의 침출율을 나타내었다. 한편 침출 초기에는 니켈과 알루미늄의 침출속도가 빠르고 60 분 이후 급격히 둔화되는 형태를 보인 반면 코발트와 크롬은 침출이 느리고 60 분 이후의 감소율만 상대적으로 적었다. 120 분 경과 시 주요 금속원소들의 침출율은 모두 99% 수준에 도달하였다. 고액비가 높아지면 침출율은 서서히 감소하였으며, 니켈과 알루미늄이 코발트와 크롬에 비하여 침출율 감소가 적었다. 염산농도 4 M, 침출온도 $90^{\circ}C$, 침출시간 120 분의 조건에서 고액비 125 g/L 이하의 조건이 주요 금속 성분의 침출에 효과적임을 확인하였으며, 이는 CMSX-4 합금의 금속학적 조직구조와 관련이 있는 것으로 생각된다.

강화형 글라스 아이오노머 합착용 시멘트의 접합강도 및 변연누출에 대한 연구 (COMPARISON OF SHEAR BOND STRENGTH AND MARGINAL LEAKAGE OF RESIN MODIFIED GLASS IONOMER CEMENTS)

  • 박혜양;오남식;이근우;이호용
    • 대한치과보철학회지
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    • 제35권4호
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    • pp.647-661
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    • 1997
  • The resin modified glass ionomer cements(RMGICs) have been used for years since 1989. Recently it has been developed for luting of fixed restorations. To evaluate the bond strength and marginal leakage of RMGICs for luting usage, the 80 extracted human molars which had uniform area of exposed dentin were cemented with 3 types of RMGICs(Fuji Duet, Advance, Vitremer), a conventional Glass Ionomer Cement(GIC-Fuji I), and a resin cement (Panavia 21) to base metal alloy(Ni-Cr-Be). After thermocycling the specimens were immersed in basic fuschin dye for measuring marginal leakage. The shear bond strength was measured with Instron and the maximum dye penetration was measured to 0.1mm. The types of fractured patterns were determined with stereoscope(${\times}7.5$). The results are as follows. 1. The difference between 3 RMGICs and a conventional GIC in shear bond strength was not statistically significant. It seemed that RMGICs had lower shear bond strength than resin cement. (p<0.01) 2. The mean scores of marginal leakage had no significant difference between the resin cement and 3 RMGICs but it was much higher in conventional GIC than the RMGICs (p<0.05) 3. It was determined that the manufacturer and the methods of dentin pretreatment determined the pattern of fracture surfaces and the frequency of adhesive failure between teeth and 3 RMGICs standed as in following order - Vitremer, Advance, Fuji Duet. (p<0. 01) When the fracture pattern was analyzed, it could be said that the materials and the method of dentin pretreatment have much effect on bonding states. This means that the dentin bonding agents should be improved. But the limited products in this experiment can not evaluate the physical properties of the entire RMGICs. Therefore a further study which can evaluate various RMGICs should be in progress to develope better cements.

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레진전장관의 금속면 처리방법 레진과 금속간 접착강도에 미치는 영향 (THE EFFECTS OF METAL SURFACE TREATMENT ON BOND STRENGTH BETWEEN RESIN AND METAL INTERFACE OF RESIN VENEERED CROWN)

  • 최낙준;방몽숙
    • 대한치과보철학회지
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    • 제32권4호
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    • pp.471-483
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    • 1994
  • The purpose of this experiment was to determine the effects of various surface treatments on veneering resin to metal bond for Ni-Cr alloy. The metal surfaces were treated as follows, Group 1 : Ground with carborudum point and followed by silicoating Group 2 : Sandblasted with $50{\mu}m$ aluminum oxide and followed by silicoating Group 3. Sandblasted with $250{\mu}m$ aluminum oxide and followed by silicoating Group 4 : Beaded with $200{\mu}m$ retention structures and followed by silicoating Group 5 : Silicoated in as cast condition Group 6. Beaded with $200{\mu}m$ retention structures only All specimens were veneered with resin. Each group was consisted of 20 specimens. 10 specimens were storaged in $37^{\circ}C$ water for 3 days and the rest 10 specimens were thermocycled 1000 times at temperature of $5^{\circ}C\;to\;55^{\circ}C$. The effects of various surface treatments on the bond strength between resin and metal interface were studied by means of four-point flexure test. The specimens which bad been ground with carborundum point. sandblasted with $50{\mu}m$ and $250{\mu}m$ aluminum oxide. beaded with $200{\mu}m$ retention structures and not been treated were observed with SEM. The following results were obtained 1. The bond strength of groups 2, 3, 4 and 6 were higher than the that of groups 1 and 5 (p<0.05) in the case of being storaged in $37^{\circ}C$ water for 3 day and there was no statistically significant difference in bond strength among groups 2, 3, 4 and 6. and between groups 1 and 5 (p>0.05). 2. The bond strength of the case of being thermocycled decreased in the following orders : groups 2, group 4, group 3, group 6, group 1, group 5 and there was no statistically significant difference in bond strength among groups 2, 3 and 4, between groups 1 and 5 (p>0.05). 3. A statistical difference in bond strength of each group between storaged and being thermocycled was demonstrated for group 5 (p<0.05). 4. The treated surfaces of groups 2, 3 and 4 had more fine undercut than that of groups 1 and 5 with SEM.

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Evaluations of Si based ternary anode materials by using RF/DC magnetron sputtering for lithium ion batteries

  • 황창묵;박종완
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2010년도 제39회 하계학술대회 초록집
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    • pp.302-303
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    • 2010
  • Generally, the high energy lithium ion batteries depend intimately on the high capacity of electrode materials. For anode materials, the capacity of commercial graphite is unlike to increase much further due to its lower theoretical capacity of 372 mAhg-1. To improve upon graphite-based negative electrode materials for Li-ion rechargeable batteries, alternative anode materials with higher capacity are needed. Therefore, some metal anodes with high theoretic capacity, such as Si, Sn, Ge, Al, and Sb have been studied extensively. This work focuses on ternary Si-M1-M2 composite system, where M1 is Ge that alloys with Li, which has good cyclability and high specific capacity and M2 is Mo that does not alloy with Li. The Si shows the highest gravimetric capacity (up to 4000mAhg-1 for Li21Si5). Although Si is the most promising of the next generation anodes, it undergoes a large volume change during lithium insertion and extraction. It results in pulverization of the Si and loss of electrical contact between the Si and the current collector during the lithiation and delithiation. Thus, its capacity fades rapidly during cycling. Si thin film is more resistant to fracture than bulk Si because the film is firmly attached to the substrate. Thus, Si film could achieve good cycleability as well as high capacity. To improve the cycle performance of Si, Suzuki et al. prepared two components active (Si)-active(Sn, like Ge) elements film by vacuum deposition, where Sn particles dispersed homogeneously in the Si matrix. This film showed excellent rate capability than pure Si thin film. In this work, second element, Ge shows also high capacity (about 2500mAhg-1 for Li21Ge5) and has good cyclability although it undergoes a large volume change likewise Si. But only Ge does not use the anode due to its costs. Therefore, the electrode should be consisted of moderately Ge contents. Third element, Mo is an element that does not alloys with Li such as Co, Cr, Fe, Mn, Ni, V, Zr. In our previous research work, we have fabricated Si-Mo (active-inactive elements) composite negative electrodes by using RF/DC magnetron sputtering method. The electrodes showed excellent cycle characteristics. The Mo-silicide (inert matrix) dispersed homogeneously in the Si matrix and prevents the active material from aggregating. However, the thicker film than $3\;{\mu}m$ with high Mo contents showed poor cycling performance, which was attributed to the internal stress related to thickness. In order to deal with the large volume expansion of Si anode, great efforts were paid on material design. One of the effective ways is to find suitably three-elements (Si-Ge-Mo) contents. In this study, the Si based composites of 45~65 Si at.% and 23~43 Ge at.%, and 12~32 Mo at.% are evaluated the electrochemical characteristics and cycle performances as an anode. Results from six different compositions of Si-Ge-Mo are presented compared to only the Si and Ge negative electrodes.

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에칭 폐액으로부터 용매추출과 가수분해를 이용한 니켈분말제조에 관한 연구 (Recovery of Nickel from Waste Iron-Nickel Alloy Etchant and Fabrication of Nickel Powder)

  • 이석환;채병만;이상우;이승환
    • 청정기술
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    • 제25권1호
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    • pp.14-18
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    • 2019
  • 여러 금속 부품을 가공하기 위하여 사용된 염화제이철 에칭 폐액은 유가금속인 니켈 등을 함유하고 있다. 본 연구에서는 식각공정을 완료한 에칭폐액을 재생하고 부산물로 나온 니켈 함유 폐액으로부터 정제하여 니켈 금속분말로 제조하는 공정을 개발하였다. 부산물인 니켈함유용액을 철 등의 불순물을 침전 제거하기 위하여 수산화나트륨 수용액을 실험을 통하여 가수분해 중화제로서 선정하였고, 이를 통하여 철 등의 불순물을 pH = 4 조건하에 침전 제거하였다. 그 후, 불순물로 잔류하는 망간 및 아연과 같은 금속이온들을 D2EHPA (Di-(2-ethylhexyl) phosphoric acid)를 사용하여 용매추출 하였다. 정제된 염화니켈은 99% 이상의 순도를 가지고 있으며, 그 후 환원제로 하이드라진을 이용하여 99% 이상의 순도와 약 150 nm의 크기를 가지는 니켈 금속분말로 제조하였다. 염화니켈 및 니켈 금속분말의 성분은 EDTA 적정법과 유도결합 플라즈마 방출분광법(inductively coupled plasma optical emission spectrometer, ICP-OES)을 이용하여 확인하였으며, 전계방사 주사전자현미경(field emission scanning electron microscope, FE-SEM), X-선 회절분석기(X-ray diffraction, XRD) 및 투과전자현미경(transmission electron microscopy, TEM)을 통하여 금속분말의 형태, 입자 크기 및 결정성과 같은 물리적 특성을 확인하였다.

지르코니아, 유리침투알루미나 및 PFM 전부관 시스템의 파절 경향에 관한 비교연구 (A comparative study on the fracture behavior of zironia, glass infiltrated alumina and PFM full crown system)

  • 이상혁;안진수;김명호;임범순
    • 대한치과보철학회지
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    • 제50권4호
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    • pp.235-242
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    • 2012
  • 연구 목적: 본 연구는 지르코니아, 유리침투알루미나 및 금속도재소부용치관의 파절강도를 비교하고자 하였다. 연구 재료 및 방법: 지르코니아, 유리침투알루미나 및 금속도재소부용합금으로 각각 15개의 치관을 제작한 후, 제작된 치관을 장축에 $30^{\circ}$ 경사지게 제작된 지그에 장착하여 만능시험기로 파절강도를 측정하였으며, 전단결합강도 시험을 위하여 지르코니아, 유리침투알루미나 및 금속도재소부용합금을 $5.5({\phi}){\times}2.5mm$ 크기로 제작하고 포세린 분말을 $3.5({\phi}){\times}2.5mm$ 크기로 축성한 후 제조사의 설명서에 따라 전기로(Ceramco 7, Dentsply, USA)에서 소결하여 총10개의 시편을 제작하였다. 결과: 전부관 형태로 제작한 시편의 파절강도는 금속-도재 시스템이 $569.1{\pm}61.8N$, 알루미나-도재 시스템이 $551.0{\pm}76.5N$ 및 지르코니아-도재 시스템이 $588.3{\pm}49.6N$으로 측정되었으며, 각 실험군간 유의한 차이는 없었다(P>.05). 전단결합강도는 금속-도재 시스템이 $38.9{\pm}5.0MPa$, 알루미나-도재 시스템이 $39.4{\pm}5.1MPa$, 지르코니아-도재 시스템이 $25.5{\pm}5.6MPa$로 지르코니아-도재 시스템이 다른 두 시스템 보다 유의하게 낮은 값을 보였다(P<.05). 금속-도재 시스템, 알루미나-도재 시스템 및 지르코니아-도재 시스템의 각 결합계면을 SEM/EDS로 분석한 결과 각 시스템에서 상이한 결합 양상이 관찰되었다. 결론: 본 연구 결과 지르코니아-도재 시스템의 파절강도가 제일 높았으며, 금속-도재 시스템, 알루미나-도재 시스템 순서로 나타났으며, 전단결합강도는 알루미나-도재 시스템이 제일 높았고 금속-도재 시스템, 지르코니아-도재 시스템 순서으로 나타났다.