• 대한치과기공학회지
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• 제8권1호
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• pp.37-43
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• 1986

The purpose of this study is to evalute the effects of melting and casting procedures on the castability of some N-Cr and Ag-Pd alloys. One Ag-Pd alloy and two Ni-Cr alloys were chosen for study, and the first casting group of these alloys were used as the control, and with which the castability of the first recase group and the mixture group of the first recast and as much amount of the first casting alloy was compared. The results of this study were as follows: 1. The castability of the first recast alloys veried significantly depending upon the presence or abscence of the first casting alloy and the kind of alloys. 2. When the first recast alloy was mixed with as much amount of the first casting alloy, there was no significant difference in castabilityh between the first recast group and the first casting group. 3. When the first recast alloy was used alone, the castability veried significantly depending upon the kind of alloys, i.e., the castability of Rexillium III and Palliag M was decreased significantly when compared with that of the first casting groups, while that of C & B Alloy was not.

• 대한치과기공학회지
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• 제43권4호
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• pp.168-174
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• 2021

Purpose: This study was conducted to investigate alloys spectrophotometrically including yttrium of nickel-chromium (Ni-Cr) alloys, which are used as substitutes for the regulation of beryllium and provide helpful improvements in Ni-Cr alloys. Methods: Four groups of specimens (ZN, ZY, SN and EM) were prepared for analysis. Color parameters were measured with a spectrophotometer, and color difference (∆E^*) was calculated. The t-test and one-way analysis of variance test were used to determine significant difference, and the Tukey test was used to identify where the differences were. To measure the spectroscopic reflectivity, the spectroscopic reflectance was measured and converted into CIE L^*, a^*, b^* color system. Results: The ∆E^* value of each metal ceramic group after opaque firing of Ni-Cr alloy with and without yttrium was <2, and the total group color difference (∆E^*) was below 1 in the dentin ceramic all experimental group. However, the a^* and b^* values of the metal ceramic groups were higher than that in the lithium disilicate all ceramic group, and the chroma was higher than the natural tooth. The brightness of all experimental groups was similar to that of the shade guide sample. Conclusion: Yttrium added to Ni-Cr alloys showed similar CIE L^*, a^*, b^* values to Ni-Cr alloys that did not contain yttrium, indicating that yttrium had no effect on color in metallic ceramic systems.

• 한국수소및신에너지학회논문집
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• 제19권1호
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• pp.35-40
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• 2008

Ni-based amorphous alloy ribbon was prepared by a single-roller melt-spinning technique. Palladium coating was found to enhance significantly the absorption/desorption behavior of hydrogen in amorphous alloy. The hydrogen permeability of a Pd-coated $(Ni_{60}Nb_{40}){_{100-X}}$TaX(x=5, 10) amorphous alloy was examined in the temperature range of $623{\sim}773K$, comparable with those of $Pd_{60}-Cu_{40}$ alloys. The permeated hydrogen flux was increased with increasing the temperature and the difference of hydrogen pressure between the feed side and permeates side of the membrane. The Ni-based amorphous alloys were characterized by X-ray diffractometry(XRD) and differential scanning calorimetry(DSC). The morphology of surface and roughness was observed by using scanning electron microscopy(SEM) and atomic force microscopy(AFM).

• Transactions on Electrical and Electronic Materials
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• 제4권1호
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• pp.15-20
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• 2003

NiCr alloys are prepared onto poly-Si/ $SiO_2$/Si substrates to replace Pt bottom electrode with a new one for integration of high dielectric constant materials. Alloys deposited at Ni and Cr power of 40 and 40 W showed optimum properties in the composition of N $i_{1.6}$C $r_{1.0}$. The grain size of films increases with increasing deposition temperature. The films deposited at 50$0^{\circ}C$ showed a severe agglomeration due to homogeneous nucleation. The NiCr alloys from the rms roughness and resistivity data showed a thermal stability independent of increasing annealing temperature. The 80 nm thick BST films deposited onto N $i_{1.6}$C $r_{1.0}$/poly-Si showed a dielectric constant of 280 and a dissipation factor of about 5 % at 100 kHz. The leakage current density of as-deposited BST films was about 5$\times$10$^{-7}$ A/$\textrm{cm}^2$ at an applied voltage of 1 V. The NiCr alloys are possible to replace Pt bottom electrode with new one to integrate f3r high dielectric constant materials.terials.

• International Journal of Precision Engineering and Manufacturing
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• 제5권1호
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• pp.19-26
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• 2004

The growth of solid particles in TiC-XC-2vo1.% and TiC-XC-30vo1.% Ni alloys, (where X=Zr, W or Mo) was fitted to the equation of the form $d^3$-${do}^3$=Kt during the liquid phase sintering at 1,673K. Also, the grain growth behavior decreased markedly with the addition of ${MO}_2$C or WC and increased with the addition of zrC. The contiguity was greater in the alloys with a smaller growth rate constant and especially, decreased by increasing the Ni content in the TiC-${MO}_2$C-Ni alloy. In addition, the effect of the addition of carbide on the grain growth of 2 vo1.% Ni alloys was found to be similar to that of 30vo1.% Ni alloys. Consequently, the grain growth mechanism cannot be explained by the usual solution / reprecipitation process, but can be explained in terms of a new growth velocity equation, which includes the effects of contiguous carbide grain boundaries in restricting the overall grain growth, as well as the area of the solid / liquid interface in the alloy.

• 한국수소및신에너지학회논문집
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• 제21권2호
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• pp.123-128
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• 2010

Hydriding combustion synthesis (HCS) can produce full hydrides of alloys and in a short time. The conventional process based on ingot metallurgy cannot produce Mg-based alloy easily with the desired composition and the cast product needs a ling activation process for the practical use of hydrogen storage. In this study, the hydriding properties of Mg-xNi (x=5, 13.5, 54.7wt.%) alloys prepared by hydriding combustion synthesis were evaluated. The hydrogen storage capacity and kinetics of HCS Mg-xNi alloys were strongly dependent on the content of Ni. The HCS Mg-13.5wt.%Ni alloy shows the hydriding behavior to reach the maximum capacity within 30 min. and the reversible $H_2$ storage of 5.3wt.% at 623 K.

• 한국재료학회지
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• 제14권4호
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• pp.251-259
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• 2004

In the development of the advanced spent fuel management process based on the molten salt technology, it is essential to choose the optimum material for the process equipment handling molten salt. Corrosion behavior of Ni 200 and Ni-base alloys in molten salt of LiCl-$Li_2$O under oxidation atmosphere was investigated in the temperature range of $650～800^{\circ}C$ for 24～312 hrs. The order of corrosion rate was Ni 200 > Inconel 690 > Inconel 601 > Inconel 600. Inconel 600 alloy showed the highest corrosion resistance among the examined alloys, but Ni 200 exhibited the highest corrosion rate. Corrosion products of Inconel 600 and Inconel 601 were $Cr_2$$O_3$ and $NiFe_2$$O_4$. In case of Inconel 690, a single layer of $CrO_2$$O_3$ was formed in the early stage of corrosion and an outer layer of $NiFe_2$O$_4$ and inner layer of $Cr_2$$O_3$ were formed with increase of corrosion time. Inconel 600 showed local corrosion behavior and Inconel 601, 690 showed uniform corrosion behavior.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.962-963
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• 2006

The precipitation behaviors of ${\gamma}"(Ni_3Nb)$ in four Ni-base alloys were investigated. The four alloys were forged Ni20Cr20Fe5Nb alloy, mechanically alloyed Ni20Cr20Fe5Nb alloy, IN 718 alloy and ECAPed(equal channel angular pressing) IN 718 alloy. Aging treatment was employed at either $600^{\circ}C$ or $720^{\circ}C$ for 20 hrs. The TEM observation and hardness test were performed to identify the formation of ${\gamma}"$. The precipitation of ${\gamma}"$ was noticed after aging at $600^{\circ}C$ for 20 hrs in the mechanically alloyed Ni20Cr20Fe5Nb alloy and ECAPed IN 718 alloy, while it was observed after aging at $720^{\circ}C$ for 20 hrs in the forged Ni20Cr20Fe5Nb alloy and IN 718 alloy before ECAP. The lower aging temperature for ${\gamma}"$ precipitation in the mechanically alloyed Ni20Cr20Fe5Nb alloy and ECAPed IN 718 alloy than in the forged Ni20Cr20Fe5Nb alloy and IN 718 alloy before ECAP appeared to be due to the severe plastic deformation which occurred during mechanical alloying or ECAP.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.953-954
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• 2006

Ti-Cu-Ni-Sn quaternary amorphous alloys of $Ti_{50}Cu_{32}Ni_{15}Sn_3$, $Ti_{50}Cu_{25}Ni_{20}Sn_5$, and $Ti_{50}Cu_{23}Ni_{20}Sn_7$ composition were prepared by mechanical alloying in a planetary high-energy ball-mill (AGO-2). The amorphization of all three alloys was found to set in after milling at 300rpm speed for 2h. A complete amorphization was observed for $Ti_{50}Cu_{32}Ni_{15}Sn_3$ and $Ti_{50}Cu_{25}Ni_{20}Sn_5$ after 30h and 20h of milling, respectively. Differential scanning calorimetry analyses revealed that the thermal stability increased in the order of $Ti_{50}Cu_{32}Ni_{15}Sn_3$, $Ti_{50}Cu_{25}Ni_{20}Sn_5$, and $Ti_{50}Cu_{23}Ni_{20}Sn_7$.

• 한국주조공학회지
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• 제21권2호
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• pp.127-134
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• 2001

Misch metal (rare earth element, Ce, La, Nd, Pr) which has large influence on high-temperature stability and toughness was added to the Al-5%Ni-5%Mg alloy, and squeeze casting was used for Al-5%Ni-5%Mg-(Mm) alloys. The effect of applied pressure and misch metal additions on mechanical properties in Al-5%Ni-5%Mg alloy by direct squeeze casting has been investigated. The applied pressure were 0 MPa(gravity casting), 25, 50 and 75 MPa. Squeeze-cast Al-5%Ni-5%Mg-(Mm) alloys had better mechanical properties than those of non-pressurized cast alloys because of the increased cooling rate by the application of pressure during solidification. By the addition of misch metal in Al-5%Ni-5%Mg alloy, better combination of strength and elongation was obtained. The addition of 0.3%Mm in Al-5%Ni-5%Mg alloy improved the heat resistant property due to the formation of fine eutectic phases.