• 동력기계공학회지
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• 제9권1호
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• pp.70-75
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• 2005

The damping property of Fe-12Cr-22Mn-X alloys has been investigated to develop high damping and high strength alloy. Particularly, the effect of the phase of austenite, alpha and epsilon martensite, which constitute the structure of the alloys Fe-12Cr-22Mn-X alloys, on the damping capacity at room temperature has been investigated. Various fraction of these phases were formed depending on the alloy element and cold work degree. The damping capacity is strongly affected by ${\varepsilon}$ martensite while the other phase, such as ${\alpha}'$ martensite, actually exhibit little effect on damping capacity. In case of Fe-12Cr-22Mn-3Co alloy, the large volume fraction of ${\varepsilon}$ martensite formed at about 30% cold rolling, and in case of Fe-12Cr-22Mn-1Ti alloy, formed at about 20% cold rolling and showed the highest damping capacity. Damping capacity showed higher value in Fe-12Cr-22Mn-1Ti alloy than one in Fe-12Cr-22Mn-3Co alloy.

• 한국자기학회지
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• 제3권1호
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• pp.7-12
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• 1993

저열팽창재료인 Fe-36%Ni 인바합금을 기본조성으로 하여 제3원소인 Mn, Cr, Co를 0-5wt% 범위에서 소량 첨가하고 자기적성질의 변화를 조사였다. 상온에서 $300^{\circ}C$까지의 온도에 따른 비자화의 변화는 조성에 따라 약간의 차이는 있지만 5wt%Co를 제외하고 상온으로 부터 큐리온도 직 하인 $250^{\circ}C$까지 온도상승에 따라 지바화가 매우 빠르게 감소하고, 첨가원소에 따른 비자화의 온도의존성이 온도의 3/2승항과 2승항을 혼합한 형태로 나타나는 인바합금 특유의 형상을 보인다. 상온에서 첨가원소에 따른 비자화, 큐리온도 및 보자력은 동일 함량으로 치환할 경우에 Co > Cr > Mn 의 순서로 높게 나타나지만, 5wt%Co의 경우에 급증하는 현상은 강자성 $\gamma$상과 반강자성 $\gamma$상이 혼재하는 인바효과가 강자성 $\alpha$ 상이 생성됨에 따라 사라지기 때문이었다.

• 대한치과보철학회지
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• 제36권2호
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• pp.336-354
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• 1998

Traditionally, many kinds of mechanical bonding techniques were used for bonding resins to the surface of the metal alloys. If there is a seperation between resin and metal junction by stress accumulation and temperature change of oral cavity, the cracks or crazing may occur, accompanied by failure of resin bonding to metal. This study was designed to compare the shear bond strength of the type IV gold alloy and Cr-Co alloy surfaces treated with various methods and thermocycling. Universal Instron (Model 1000) and scanning electron microscope (JEOL, Japan) was used to record the shear bond strength of 5 groups. Forty specimens were made for each group ; group 1 was treated with sandblasting only, group 2 was coated with V-primer after sandblasting, group 3 was coated with Metal primer, group 4 wase coated with MR Bond and group 5 was coated with silane. After treated with various methods, thermocycling was done for half of the each group. The surfaces of failed pattern were observed with SEM. The results were as follows : 1. Shear bond strength of the group 1 was lower than that of another groups in type IV gold alloys and bond strength of the group 1, 2 were lower than that of group 3, 4, 5 in Cr-Co alloys. 2. Shear bond strength of the gold alloy with resin was higher than that of Cr-Co alloy when specimens were coated with V-primer. 3. Shear bond strength of the Co-Cr alloys with resin was higher than that of gold alloys when specimens were coated with Metal primer. 4. The bond strength of all specimens did not decreased significantly after thermocycling. 5. Adhesive failures were found in group 1 and Cr-Co alloy in group 2, but adhesive and cohesive failures were found in another groups.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.708-709
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• 2006

New Al-based alloys with very high ultimate tensile strength were developed in high Al concentration range of 91-95 at.% for Al-Fe-Cr-Ti-M (M: Co and Mo) systems and Al-Fe-Cr-Mo-Ti-Co system by the dispersion of nanoscale quasicrystalline particles in Al phase. The effect of adding elements, M was discussed in the viewpoint of stability of super-cooled liquid state and formation ability of quasicrystalline phase. The P/M Al-Fe-Cr-Ti-M alloys with dispersed nanoscale quasicrystalline particles exhibited ultimate tensile strength of 350MPa at 573K and 200MPa at 673K.

• 대한치과기공학회지
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• 제28권2호
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• pp.321-329
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• 2006

The popularity of Ni-Cr-Mo based metal alloys for metal-ceramic crown have increased recently because of low price, superior yield strength and rigidity. the use of these alloys give them the potential advantage of thinner copping with the required rigidity for long span bridges. The purpose of this study was to assess the microstructures and mechanical properties of Ni-Cr-Mo-(Si,Al,Nb,Zr,Ti.Cu,Mm) based Alloys not containing beryllium(Be) related toxic effects. The abtained results indicated that as-cast these specimen alloys showed compositional and microstructural differences, and mechanical properties values of Ni69Cr20Mo5Si2Al4 alloy among these specimen alloys was found to be superior to those of commercial Ni-Cr based alloy using in market place today.

• 한국분말재료학회지
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• 제3권2호
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• pp.86-90
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• 1996

The effects of added VC, Cr$_3$C$_2$ and TaC on the microstructures and properties of submicron WC-10%Co cemented carbides. The relative sintered density of compact was increased by addition of Cr$_3$C$_2$ but decreased oppositely by addition of VC or TaC. The growth of WC grains was significantly suppressed by addition of these carbides. The hardness of these alloys was increased by addition of other carbides and showed a maximum value by simultaneously added VC and Cr$_3$C$_2$. The transverse rupture strength(T.R.S.) was in- creased by addition of Cr$_3$C$_2$, while it was decreased by addition of VC or TaC. The relative sintered density and T.R.S. of these alloys were improved by HIP-treatment. The maximum T.R.S. was 328kg/mm$^2$ in the Wc-10%Co cemented carbide with addition of 0.5%VC.

• 한국표면공학회지
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• 제43권4호
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• pp.199-204
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• 2010

The Co-Cr alloys have clinical histories as dental and orthopaedic implants, and recently as cardiovascular stent applications because they exhibit a high elastic modulus and radiopacity. In order to improve their mechanical and corrosion resistance, electropolishing is employed as the final process. Electropolishing, an anodic dissolution process in the transpassive state, is sensitively affected by process conditions such as current density, machining time, and electrode gap. In this study, the effect of the electropolishing conditions on surface roughness and corrosion resistance is investigated for Co-Cr alloys (L605). The most smooth surface is obtained when electropolishing is performed at 15-20 V for 15-30 sec with a electrode gap of 3.5 mm. It is found out that electropolishing reduces corrosion rate about one-tenth as much.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 1993년도 추계연구발표회 논문개요집
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• pp.76-77
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• 1993

• The Journal of Advanced Prosthodontics
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• 제13권3호
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• pp.127-135
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• 2021

Purpose. The aim of this study is to compare the hardness according to the conditions of metal alloys. Moreover, the correlation between the cast crown hardness before and after wear testing and the degree of wear for each dental alloy was assessed. Materials and Methods. Cast crowns of three metal alloys (Co-Cr, gold, and Ni-Cr alloys) opposing smooth-surface monolithic zirconia were used. The Vickers microhardness of the ingot (which did not undergo wear testing) and the cast crown before and after wear testing were measured for each alloy. Two-way ANOVA and Scheffé tests were used to compare the measured hardness values. Moreover, the Pearson correlation coefficient was used to evaluate the relationship between the surface hardness and the wear of the cast crown (α=.05). Results. There was no significant difference in the hardness before and after wear testing for the gold alloy (P>.05); however, the hardness of the worn surface of the cast crown increased compared to that of the cast crown before the wear tests of Ni-Cr and Co-Cr alloys (P<.05). Furthermore, there was no correlation between the wear and hardness of the cast crown before and after wear testing for all three metal alloys (P>.05). Conclusion. There was a significant difference in hardness between dental alloys under the same conditions. No correlation existed between the surface hardness of the cast crown before and after wear testing and the wear of the cast crown.

• 대한치과기공학회지
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• 제35권2호
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• pp.105-112
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• 2013

Purpose: This study was to analyze the castability, surface oxide characteristic of Co-Cr alloy for porcelain fused to metal crown and the bonding strength of porcelain fused to metal crown. Co-Cr and Ni-Cr alloy for porcelain fused to metal crown was used for tests of the castability and surface oxide state and shear bonding strength by various porcelain. The aim of this study was to suggest the differences of result according to Co-Cr and Ni-Cr alloy. Methods: The kinds of alloy as test specimen was Co-Cr and Ni-Cr alloy. The castability index on the alloy specimens. The surfaces of two alloys were analyzed by SEM and EDX in order to observe oxide characteristic. And the shear test was performed by MTS. Results: The castability index of Co-Cr alloy was 96.8% and Ni-Cr alloy was 94.4%. The strongest bonding strength of Co-Cr alloy was shown 67.37 MPa. Conclusion: The shear bonding strength between Co-Cr alloy and EX3 porcelain was the strongest comparing with others. And all of each alloy was indicated as same level about the castability.