• Title, Summary, Keyword: Co-base alloy

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Study on Base metal Alloy (Base metal Alloy에 관한 고찰(考察))

  • Sung, Hwan-Kyung
    • Journal of Technologic Dentistry
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    • v.7 no.1
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    • pp.53-59
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    • 1985
  • This paper aims to examine baes metal alloy in all its aspects - the roles of elements, the content of every element according to uses, characters, laboratory technique methods and the kind of artificial base metal alloy registered in A.D.A. Specification. The results are as follows; 1. Base metal alloy is used widely bacaues it is rather cheap, but it should be handled appropriately in operating because its quality is bad. 2. Classifying base metal alloy, it is classified into Co-Cr alloy, Ni-Cr alloy, and Ni-Cr-Co alloy according to element, it is classified into partial denture alloy, surgical alloy and crown & bridge alloy according to use. 3. Among elements of base metal alloy, Bellium lowers the melting point of the alloy and increases the strength, but the amount should be limited when it is used because it destroys the organization of a living body. 4. The investments for base metal alloy are ethyl silcate bonded investment and phosphate bonded investment which endure well at high burn out temperature. 5. A.D.A specification No.14 in Kore contains Niranium, Nobilium, regalloy, Ticonium and Vitallium.

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Effects of Alpha Phase on the Fatigue Properties of Fe-29%Ni-17%Co Low Thermal Expansion Alloy (Fe-29%Ni-17%Co 저열팽창 합금의 피로 특성에 미치는 알파상의 영향)

  • Kim, Min-Jong;Gwon, Jin-Han;Cho, Kyu-Sang;Lee, Kee-Ahn
    • Korean Journal of Materials Research
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    • v.24 no.9
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    • pp.481-487
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    • 2014
  • The effect of alpha phase on the fatigue properties of Fe-29%Ni-17%Co low thermal expansion alloy was investigated. Two kinds of alloys (Base alloy and Alpha alloy) were prepared by controlling the minimal alloy composition. Microstructure observation, tensile, high-cycle fatigue, and low-cycle fatigue results were measured in this study. The Base alloy microstructure showed typical austenite ${\gamma}$ phase. Alpha alloy represented the dispersed phase in the austenite ${\gamma}$ matrix. As a result of tensile testing, Alpha alloy was found to have higher strengths (Y.S. & T.S.) and lower elongation compared to those of the Base alloy. High cycle fatigue results showed that Alpha alloy had a higher fatigue limit (360MPa) than that (330MPa) of the Base alloy. The Alpha alloy exhibited the superior high cycle fatigue property in all of the fatigue stress conditions. SEM fractography results showed that the alpha phase could act to effectively retard both fatigue crack initiation and crack propagation. In the case of low-cycle fatigue, the Base alloy had longer fatigue life in the high plastic strain amplitude region and the Alpha alloy showed better fatigue property only in the low plastic strain amplitude region. The fatigue deformation behavior of the Fe-29%Ni-17%Co alloy was also discussed as related with its microstructure.

THE EFFECTS OF THERMOCYCLING ON THE BOND STRENGTH BETWEEN COBALT-CHROMIUM ALLOY AND DENTURE BASE RESIN (Thermocycling이 Cobalt-Chromium 합금과 의치상 레진의 결합강도에 미치는 영향)

  • Lee, Su-Yeon;Vang, Mong-Sook
    • The Journal of Korean Academy of Prosthodontics
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    • v.38 no.1
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    • pp.38-49
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    • 2000
  • The purpose of this study was to evaluate the effects of thermocycling on the shear bond strength of Co-Cr alloy to denture base resin. PMMA denture base resin such as heat-cured $Vertex-RS^{(R)}$, self-cured $Vertex-SC^{(R)}$ and 4-META denture base resin such as heat-cured $Meta-Dent^{(R)}$, self-cured $Meta-Fast^{(R)}$ was bonded to Co-Cr alloy. Samples were divided into 3 groups : no thermocycling group as control, thermocycling between $5^{\circ}C\;and\;55^{\circ}C$ with 15 second dwell time as group 1, thermocycling with 1 minute dwell time as group 2. The shear bond strength was measured and the interface between metal and resin was observed by SEM. The results were as follows. 1. The shear bond strength decreased significantly according to thermocycling and dwell time(P<0.001). 2. The bond strength of Co-Cr alloy and 4-META denture base resin was significantly higher than that of Co-Cr alloy and PMMA denture base resin(P<0.001) 3. In SEM, there was no gap in control group, but there was much and large gap in group 1, 2. The longer dwell times, the lower bond strength. PMMA denture base resin had more gap than 4-META denture base resin in the interface. These results revealed that thermocycling decreased the bond strength between Co-Cr alloy and denture base resin and dwell time of thermocycling changed the effect of thermocycling. The results suggested that oral temperature change affect the bond strength of prosthesis.

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A Study on the Surface Modification of the Super Alloy by Plasma Transferred Arc Overlay Welding Method

  • Kim, Young-Sik;Lim, Chang-Hoon;Hwang, Won-Seok;Choi, Young-Gook
    • Journal of Advanced Marine Engineering and Technology
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    • v.31 no.7
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    • pp.852-856
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    • 2007
  • The Plasma Transferred Arc(PTA) overlay welding method is lately introduced as one of the most useful surface overlay method of the engine component. In this paper, the overlay welding method on the Nimonic super alloy was established by the PTA overlay welding process using the same super alloy powder. The characteristics of the Co-base and Ni-base super alloy overlay layers were investigated through the metallurgical, abrasive and cavitation erosion test. The abrasive and cavitation characteristics were investigated at room and high temperature.

A Study on the Characteristics of the Ni base Super Alloy Overlay Layer by Plasma Transferred Arc (PTA) Method (Ni 계 초내열합금의 PTA 오버레이 층 특성에 관한 연구)

  • Kim Young-Sik;Choi Young-Goog;Lee Kwang-Ryeol
    • Journal of Welding and Joining
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    • v.24 no.3
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    • pp.49-54
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    • 2006
  • The Plasma Transferred Arc (PTA) overlaying method is lately introduced as one of the most useful surface modification method of the engine component. In this paper, the characteristics of the Co-base and Ni-base super alloy overlay layers by PTA method were investigated through the metallurgical, abrasive and cavitation erosion test. Experimental results showed that the abrasive wear resistance of the Co-base Stellite 6 overlayer was the most superior and followed in order of Nimonic 80A, Inconel 625 and Inconel 718. However, the cavitation erosion characteristic of the Stellite 6 overlayer was the most inferior and it was better in order of Inconel 625, Inconel 718 and Nimonic 80A.

Comparison of the marginal and internal fit of cores fabricated by Ni-Cr alloy(non-beryllium) and Co-Cr alloy (베릴륨이 함유되지 않은 니켈-크롬 합금 코어와 코발트-크롬 합금 코어의 적합도 비교평가)

  • Kim, Ki-Baek;Kim, Jae-Hong;Kim, Woong-Chul;Kim, Ji-Hwan
    • Journal of Technologic Dentistry
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    • v.34 no.4
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    • pp.353-359
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    • 2012
  • Purpose: The aim of this study measured and compared the marginal and internal fit of metal cores with two base metal alloy (Ni-Cr alloy(non-beryllium), Co-Cr alloy). Methods: Maxillary right first molar abutment fabricated by titanium was prepared for this study. Impressions(10ea) were made from titanium model, and study models were poured with improved dental stone. Wax cores of twenty were prepared for burn-out and casting. Ten wax cores cast Ni-Cr alloy(non-Be), and finally ten cast Co-Cr alloy. Marginal and internal fit of cores was evaluated using silicone replica technique and digital microscope(x160). The data were statistically analyzed with the independent samples t-test (${\alpha}$ <.05). Results: Mean(standard deviation, SD) marginal and internal fit total size of Ni-Cr alloy(non-Be) group was $73.3(14.4){\mu}m$ and of Co-Cr alloy group $65.6(17.4){\mu}m$. The marginal and internal fit total size of Ni-Cr alloy group(non-Be) was statistically significantly greater than that of Co-Cr alloy group (P=.004). Conclusion: Co-Cr alloy cores in this study had a better marginal fit than Ni-Cr alloy(non-Be) cores.

The effect of Zirconium Nitride coating on shear bond strength with denture base resin in Co-Cr alloy and titanium alloy (질화 지르코늄 코팅이 코발트 크롬 합금과 타이타늄 합금에서 의치상 레진과의 전단결합강도에 미치는 영향)

  • Park, Chan;Lee, Kyoung-Hun;Lim, Hyun-Pil
    • Journal of Dental Rehabilitation and Applied Science
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    • v.32 no.3
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    • pp.194-201
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    • 2016
  • Purpose: The purpose of this study was to evaluate of Zirconium Nitride (ZrN) coating on shear bond strength with denture base resin in Co-Cr and Ti-6Al-4V alloy. Materials and Methods: Co-Cr and Ti-6Al-4V alloy disks (10 mm in diameter, 2.5 mm in thickness; each other: n = 14) were prepared and divided with 2 groups each other by ZrN coating. After primer was applied to disks surface, denture base resin with diameter 6 mm, height 5 mm was bonded on metal disk surface. After surface roughness was measured by Profiler, shear bond strength was determined with Universal testing machine and analyzed with two-way ANOVA. The specimen surfaces and failure mode were examined using a scanning electron microscope. Results: ZrN coated groups showed significantly higher rough surface than non-coated groups (P < 0.05). Irrespective of alloy materials, shear bond strength of ZrN coated groups were lower than non-coated groups (P < 0.001). The scanning electron microscope (SEM) of ZrN coated groups showed mixed and adhesive fractures. Conclusion: ZrN coating weakened bonding strength between denture base resin and Co-Cr, Ti-6Al-4V alloy.

Co-Re-based alloys a new class of material for gas turbine applications at very high temperatures

  • Mukherji, D.;Rosler, J.;Wehrs, J.;Eckerlebe, H.;Gilles, R.
    • Advances in materials Research
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    • v.1 no.3
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    • pp.205-219
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    • 2012
  • Co-Re alloy development is prompted by the search for new materials for future gas turbines which can be used at temperatures considerably higher than the present day single crystal Ni-based superalloys. The Co-Re based alloys are designed to have very high melting range. Although Co-alloys are used in gas turbine applications today, the Co-Re system was never exploited for structural applications and basic knowledge on the system is lacking. The alloy development strategy therefore is based on studying alloying additions on simple model alloy compositions of ternary and quaternary base. Various strengthening possibilities have been explored and precipitation hardening through fine dispersion of MC type carbides was found to be a promising route. In the early stages of the development we are mainly dealing with polycrystalline alloys and therefore the grain boundary embrittlement needed to be addressed and boron addition was considered for improving the ductility. In this paper recent results on the effect of boron on the strength and ductility and the stability of the fine structure of the strengthening TaC precipitates are presented. In the beginning the alloy development strategy is briefly discussed.

Effect of Heat Treatment on the Microstuctures and Mechanical Properties of TiC Dispersed Ni-base Alloy (TiC 분산된 니켈기 합금의 미세조직 및 기계적 특성에 미치는 열처리 영향)

  • Hong, Seong-Hyeon;Hwang, Keum-Chul;Rhee, Won-Hyuk;Chin, Eog-Yong
    • Journal of Korean Powder Metallurgy Institute
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    • v.9 no.6
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    • pp.455-462
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    • 2002
  • The microstructures and properties of TiC dispersed nickel-base alloy were studied in this work. The alloy prepared by powder metallurgical processing was solution treated, 1st-aged at $880^{\circ}C$ for 16 hours, and then 2nd-aged at $760^{\circ}C$ for 4 hours. Microstucture of sintered specimen showed that TiC particles are uniformly dispersed in Ni base alloy. In the specimen aged at $880^{\circ}C$ for 8 hours, the fine $\gammaNi_3$(Al,Ti) precipitates with round shape are observed and the very fine $\gammaNi_3$(Al,Ti) particles with round shape are precipitated in the specimen aged at $760^{\circ}C$ for 4 hours. The presence of ${\gamma}$precipitates in TiC/Ni base alloy increased the hardness and wear resistance of the specimen. The hardness and wear resistance of the Ni-base with TiC are higher than those of conventional Ni-base superalloy X-750 because of dispersion strengthening of TiC particles. The hardness, transverse rupture strength and resistance of the specimen 2nd-aged at $760^{\circ}C$ for 4 hours are higher than those of 1st-aged specimen due to ultrafine $\gammaNi_3$(Al,Ti) precipitates.

A Study on the Abrasive Wear Properties of the PTA Overlay Layers using the Super Alloy Powder (초내열합금분말에 의한 PTA 오버레이부의 연삭 마모 특성 연구)

  • Kim, Young-Sik;Choi, Young-Gook;Lim, Chang-Hoon;Kim, Jong-Do
    • Journal of Welding and Joining
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    • v.27 no.3
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    • pp.80-84
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    • 2009
  • The Plasma Transferred Arc (PTA) overlay welding method is lately introduced as one of the most useful surface overlay method of the engine component. In this paper, the overlay welding on the SNCrW heat resisting alloy was conducted by the PTA overlay welding process using the super alloy powder. The characteristics of the overlay layers were investigated through the metallurgical and abrasive test. Experimental results showed that the overlay on the SNCrW heat resisting alloy surface was successfully made without hot cracking. The friction wear characteristics of the Co-base Stellite 6 overlayer were most superior. However the abrasive wear characteristics were most inferior in the Co-base Stellite 6 overlayer.