• 대한치과기공학회지
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• 제28권1호
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• pp.19-26
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• 2006

The effect of Nb on interfacial bonding characteristics of Ni-Cr alloy for porcelain fused to metal crown (PFM) has been studied in order to investigate oxide layer. A specimens of Ni-Cr alloy, which is 0.8mm in thickness, within the porcelain furnace of 1,000$^{\circ}C$ with four tests such as air, vacuum, air for 5 minutes and vacuum for 5 minutes in order to examine an oxide behavior of alloy surface generated by the adding of Nb to be controlled at a rate of 0, 1, 3 and 5. Oxide film was observed form of the fired specimens with scanning electron microscope (SEM), and at the same time it measured Electron Probe Micro Analyzer (EPMA). The result of this study were as follows: 1. Cr oxide film and Nb oxide film were observed from the surface of specimen to be controlled at a rate of Nb 1%. 2. Nb oxide film was observed from the interface of specimens to be controlled at a rate of Nb 1% and 3%. 3. The stability of oxide films that treated in air were more stable than treated under vacuum.

• 한국주조공학회지
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• 제27권3호
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• pp.120-125
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• 2007

The microstructure, mechanical properties and melting range of Ni-Cr-Mo based alloys were investigated to develop Be-free Ni-Cr-Mo base dental alloys for Porcelain-Fused-to-Metal Firing(PFM). All as-cast alloys showed dendritic structure. Rockwell hardness of 20Cr7Mo was increased with addition of Si and Ti. On the contrary, it was decreased with addition of Co. The duplex alloying elemental addition such as 3Co + xTi, 2Si + xCo and 2Si + xTi to 20Cr7Mo resulted in much increase of hardness. Rockwell hardness and compressive strength for 20Cr3CoSiTi or 17Cr6CoSiTi alloy that add Si-Ti had similar values compared to the commercial alloys. Melting range for 20Cr3CoSiTi and 17Cr6CoSiTi alloy that add Si-Ti showed similar or lower than commercial alloys. In conclusion, 20Cr3CoSiTi and 17Cr6CoSiTi alloys can be applied for commercial use.

• 대한치과기공학회지
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• 제27권1호
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• pp.97-104
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• 2005

The effect of Nb on interfacial bonding characteristics of Ni-Cr alloy for porcelain fused to metal crown (PFM) has been studied in order to investigate oxide layer. A specimens, which is 0.8mm in thickness, were fired at 1,000$^{\circ}C$ with four tests such as air, vacuum, air for 5 minutes and vacuum for 5 minutes in order to examine an oxide behavior of alloy surface generated by the adding of Nb to be controlled at a rate of 0, 1, 3 and 5. It observed oxide film form of the fired specimens with optical microscope and scanning electron microscope (SEM), and chemical formation of them with energy disperse X-ray spectroscopy (EDX). The other specimens, which is 2mm in thickness, were fired at 1,000$^{\circ}C$ with air and vacuum in order to analyze the diffusion behaviors of alloy-porcelain interface by X-ray dot mapping. The results of this study were as follows: 1. The observation of microstructure of specimens by SEM showed that the more Nb content is high, the more much intermediate compound of rich Nb is observed. 2. The surface morphology of oxide film is most dense in 3% Nb. The heat treatment in air constitutes denser oxide film than heat treatment under vacuum. 3. The diffusion behavior of oxide layer by X-ray dot mapping showed that Si, Al of porcelain diffuse toward metal.

• 치위생과학회지
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• 제9권4호
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• pp.405-412
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• 2009

본 연구는 도재소부용 비귀금속에 Au 코팅 층을 형성하고, Au 코팅 층이 금속-도재의 결합력에 미치는 영향을 알아보고자 2출 굴곡 시험 후에 SEM/EDS 방법으로 조사하여 비교하였다. 1. Ni-Cr ally 군과 Co-Cr alloy 군, 그리고 Ti 군의 절단면 시편의 전자현미경 사진에서 Au 코팅 층은 산화층의 확산을 제어하는 것으로 관찰되었다. 2. 2축 굴곡 시험 후에 EDS 분석 결과 Ni-Cr alloy 군과 Co-Cr alloy 군에서 Si 함량은 Au 코팅 층을 형성한 시편에서 약간 감소하였고, 결합실패의 형태는 cohesive failure와 adhesive failure가 혼재된 양상으로 관찰되었다. 3. Ni-Cr alloy 군과 Co-Cr alloy 군에서 Au 코팅 층은 도재-금속 결합력에 미치는 영향은 미미하였다. 4. Ti 군의 결합실패 형태는 Ni-Cr alloy 군과 Co-Cr alloy 군에 비해서 adhesive failure 양상이 두드러지게 관찰되었고, Au 코팅 층은 도재-금속 결합력에 영향을 미치지 않았다. 이상의 결과 비귀금속에 적용한 Au 코팅은 산화층의 확산을 제어 하는 것으로 관찰 되었으나, 금속-도재 간의 결합력 증징에 미치는 효과는 미미하였다. Au 코팅을 이용하여 금속-도재 간의 결합력 증진을 위해서는 많은 연구가 지속되어야 할 것으로 사료된다.

• 대한치과기공학회지
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• 제41권2호
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• pp.71-80
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• 2019

Purpose: In this study, to evaluate the effect of oxide changes on the shear bond strength according to the composition of Ni-Cr alloys for porcelain fused matal crown, T-4 alloys, Zeroy alloys and Zeroy-X alloys were selected. Methods: 20 specimens were fabricated using selected Ni-Cr alloys and porcelain powders. A Ni-Cr alloy having a diameter of 5 mm and a height of 25 mm was produced and the metal surface was polished. Porcelain powder was fired on the polished metal surface to a diameter of 5 mm and a height of 3 mm. The experiment group consisted of three groups, T-4(TNA), Zeroy(ZNA) and Zeroy-X(ZXA). The fabricated specimens were mounted on a jig of a universal testing machine(UTM) and fracture strength was measured by applying a shear force at a UTM crosshead speed of 0.5 mm/min. The fracture strength was calculated as the bond strength between the porcelain and the alloy. The surface of the fractured alloy was analyzed by X-ray diffraction(XRD) and scanning electron microscopy(SEM), and the components of the oxide were measured by energy dispersive X-ray spectroscopy(EDX) line profile method. Results: In SEM, XRD and EDX analysis, yttrium tended to increase the mechanical and chemical bonding forces. The shear bond strength of ZXA group containing yttrium showed the highest value at 27.53 MPa. Conclusion: Based on the results of this study, it is considered that the yttrium-added Ni-Cr alloy is clinically acceptable in porcelain shear bond strength.

• 구강회복응용과학지
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• 제22권3호
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• pp.203-210
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• 2006

Although porcelain fused to metal crowns made from non-precious metal have good mechanical properties, they also have disadvantages such as the poor biological acceptability and the low corrosional resistance. Titanium is used as the alternative metal for porcelain fused to metal crowns, in spite of difficulties in casting. For that reason non-precious alloy including titanium which is easy to cast is currently used. This study evaluated the bond strength between non-precious alloy including titanium and Ni-Cr alloy. $Tilite^{(R)}V$ as non-precious alloy including titanium, $Rexilium^{(R)}V$ as Ni-Cr alloy and $Omega900^{(R)}$ and $Vintage(Regular)^{(R)}$ as porcelain powders were used. The results were as follows. 1. In comparison with the kind of alloy, the bond strength of $Tilite^{(R)}V$ was lower than that of $Rexilium^{(R)}V$. There was no significant difference between two groups. 2. In comparison with the kind of porcelain powder, the bond strength of $Omega900^{(R)}$ was higher than that of $Vintage(Regular)^{(R)}$ in $Tilite^{(R)}V$. There was significant difference between two groups(p < 0.05).

• 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.

• 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.