• 한국표면공학회지
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• 제36권6호
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• pp.461-465
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• 2003

The microstructures and magnetic properties of electrodeposited Fe-45 wt%Ni-P alloys have been investigated. The structures of electrodeposited Fe-45 wt%Ni alloy was FCC i.e. ${\gamma}$ phase and the size of crystallite was 10 nm. The structure of electrodeposited Fe-45 wt%Ni-1 wt%P alloy showed ${\gamma}$ phase and 7 nm sized nanocrystalline. The electrodeposited Fe-45 wt%Ni-P alloys containing 2∼3 wt% of P exhibited ${\gamma}$ ＋ $\alpha$ dual phases. The electrodeposited Fe-45 wt%Ni-P alloys above 3.5 wt% showed an amorphous structure. P in the alloys acted grain refining and phase changing element. The resistivity of the electrodeposited alloys increased with P contents. Effective permeability at high frequency (above 1 MHz) increased with P contents up to 2 wt% and this was ascribed to the easier magnetization rotation owing to the reduction of eddy current. Effective permeability decreased with P contents above 3 wt% and this was ascribed to the transformation of the ferromagnetism of Fe-45 wt%Ni alloy gradually into paramagnetism with the introduction of P into the electrodeposited alloy matrix.

• 한국주조공학회지
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• 제29권4호
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• pp.169-175
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• 2009

Effect of iron and manganese contents on die soldering reaction has been studied in Al-9wt.%Si-0.3wt.%Mg alloy. Ternary ${\alpha}_{hcp}-Al_8Fe_2Si$ and ${\alpha}_{bcc}-Al_8Fe_2Si$ intermetallic compounds formed by interaction diffusion between Al-Si-Mg system alloy melt and SKD61 die steel surface. Thickness of soldering reaction layer in die steel surface decreased as Fe and Mn contents of the melts increased : When Fe content of Al-9wt.%Si-0.3wt.%Mg melts at constant 0.5wt%Mn content was 0.15wt.%, 0.45wt.% and 0.6wt.%, thickness of soldered layer of each alloy was $64.5{\mu}m,\;57.3{\mu}m$ and $46.9{\mu}m$ respectively. For Mn content of the alloy melts at constant 0.45wt.%Fe content was 0.30wt.%, 0.50wt.% and 0.70wt.%, thickness of soldered layer of each alloy was $66.1{\mu}m,\;57.3{\mu}m$ and $48.3{\mu}m$ respectively.

• 멤브레인
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• 제24권6호
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• pp.491-497
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• 2014

PTMSP[Poly(1-trimethylsilyl-1-propyne)]에 TEOS (tetraethoxysilane), TMOS (tetramethoxysilane), MTMOS(methyltrimethoxysilane), 그리고 PTMOS (phenyltrimethoxysilane)의 함량을 0, 15, 20, 30 wt%로 달리하여 졸-겔법을 이용하여 PTMSP-silica 복합막을 제조하였다. PTMSP-silica 복합막의 알콕시실란 함량에 따른 $H_2$, $N_2$의 기체투과도와 $N_2$에 대한 $H_2$의 이상 선택도를 조사하였다. $H_2$와 $N_2$의 투과도는 알콕시실란 함량이 0~20 wt% 범위에서는 증가하다가 알콕시실란 함량이 20~30 wt% 범위에서는 감소하였다. $N_2$에 대한 $H_2$의 이상 선택도는 TEOS와 PTMOS의 함량이 0~15 wt% 범위에서는 감소하였으며, 15~30 wt% 범위에서는 다시 증가하였다. Robeson upper bound와 비교할 때, PTMSP-silica 복합막은 TEOS 함량이 30 wt%, MTMOS 함량이 20 wt% 그리고 PTMOS 함량이 30 wt%에서 투과도와 이상 선택도가 동시에 향상된 것으로 나타났다.

• 한국재료학회지
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• 제7권11호
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• pp.1012-1017
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• 1997

Mg-Zn-Ca합금의 잉곳트는 BN을 내벽에 바른 4x$10^{-5}$Torr의 진공의 석영관내에서 제조하였다. Mg-Zn합금계의 입자미세화를 위하여 0.5-5wt.%조성범위의 Ca를 첨가하였다. 제조된 합금을 용체화처리한 후 결정립크기와 경도를 측정하였다. Mg-6wt.%Zn합금의 입자미세화효과는 Ca가 1.5wt%첨가 될 때 최적의 조건이었다. Mg-6wt.% Zn과 Mg-6wt.% Zn-2wt.% Ca및 Mg-6wt.% Zn-1.5wt.% Si합금을 시효처리하여 시효거동을 조사하였다. 입자미세화에 의한 경도증가효과는 Mg-Zn-Ca합금계에서 크게 나타났으며 시효에 의한 경도증가효과는 Mg-Zn-Si합금계에서 크게 나타났다. Mg-6wt.%Zn합금의 부식전류밀도는 0.5wt.% Ca의 조성에서 감소되었다.

• 한국세라믹학회지
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• 제39권3호
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• pp.217-221
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• 2002

Si and ${\alpha}-Si_3N_4$ powder mixtures added with 3 wt% $Y_2O_3$ were reacted under 5 MPa nitrogen pressure. The reaction products contained ${\alpha}-Si_3N_4$ particles with elongated shapes. Length and width of the elongated grains were the maximum when the starting powder mixture of 50 wt% Si - 47 wt% ${\alpha}-Si_3N_4$ and 3 wt% $Y_2O_3$ was used. Aspect ratio of the elongated grains were between 4.4 and 5. When the starting powder mixture contained 70 wt% Si, large particles with irregular shapes appeared. Meanwhile, the reaction did not proceed when the starting powder mixture contained 30 wt% Si and less. The SHS product was easy to crush and the elongated particles obtained from the starting powder mixtures of 40 wt% Si - 57 wt% ${\alpha}-Si_3N_4$ - 3 wt% $Y_2O_3$ and 50 wt% Si - 47 wt% ${\alpha}-Si_3N_4$ - 3 wt% $Y_2O_3$ were good candidates for the seeds.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1991년도 추계학술대회 논문집
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• pp.37-39
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• 1991

This paper is studies the effects of additives on the magnetic properties of Sr-ferrite. The specimens have been composed of SrO and Fe$_2$O$_3$with ratio of 1:5.9. As 1st additives, it is mixed to 0.2wt%, 0.7wt% and 1wt% of CaCo$_3$with 0.3wt% SiO$_2$. As 2nd addition, it is mixed to 0.5wt%, 1wt% of Na$_2$SiO$_3$, 0.5wt%, 1wt% of Cr$_2$O$_3$and 0.5wt%, 1wt% of Al$_2$O$_3$and sintering conditions was carried out at 1210$^{\circ}C$, 1230$^{\circ}C$ and 1250$^{\circ}C$. From experiments on the magnetic properties of specimen, the results were shown follows; (1) In case of additive SiO$_2$and CaO, it is stable magnetoplumbite structure for liquid phase grown, enhances mignetic propertics. (2) In case of basic compositions + 0.5wt% Al$_2$O$_3$, it is confirmed better properties by increasing of the coercivity than 0.5wt% Cr$_2$O$_3$additives. (3) In case of mixed additives of Cr$_2$O$_3$and Al$_2$O$_3$, magnetic propeties decrease with sintering density.

• 한국세라믹학회지
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• 제23권5호
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• pp.9-16
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• 1986

The effect of $TiO_2$ addition to the 90wt% Cordierite-10wt% Enstatite base glass was investi-gated to understand the crystallization behavior of the glass. Glasses with addition of $TiO_2$ less than 7, 5wt% had a tendency of surface crystallization and were cracked when heat treated and in this case the crystalline phase formed was indialite. glasses with addition of $TiO_2$ more than 10wt% to 15wt% were crystallized in bulk when heat treated and were suitable for glass-ceramics. The highest microhardness 1640kg/$mm^2$ was obtained when the glass of 12.5wt% $TiO_2$ addition was heat treated at 762$^{\circ}C$ for 60 minutes for nucleation and at 1135$^{\circ}C$ for 20 minutes for crystal growth and in general higher microhardness was obtained when crystalline phase of magnesium aluminum titanate and $\mu$-cordierite were developed. Avrami equation for crystal growth kinetics was applicable in glasses of less than 7.5 wt% $TiO_2$ addition and in case of glasses of more than 10wt% $TiO_2$ addition it was not applicable because of too fast crystal growth.

• 한국주조공학회지
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• 제31권1호
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• pp.18-25
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• 2011

Effect of Fe and Mn contents on the tensile properties has been studied in Al-9wt%Si-0.3wt%Mg alloy. As Fe content of Al-9wt%Si-0.3wt%Mg-0.5wt%Mn alloy increased from 0.15wt% to 0.45wt%, tensile strength of as-cast alloy decreased from 192 MPa to 174 MPa, and elongation of the alloy also decreased from 4.8% to 4.2%. Decrease of these properties can be explained as the formation of plate shape, ${\beta}-Al_5FeSi$ phase with high Fe/Mn ratio of the alloy. However when Mn content of Al-9wt%Si-0.3wt%Mg-0.45wt%Fe alloy increased from 0.3wt% to 0.5wt%, tensile strength of T6 aged alloy increased from 265 MPa to 275 MPa, and elongation of the alloy increased from 2.3% to 3.6%. These improvements attribute to chinese script, ${\alpha}-Al_{15}(Mn,Fe)_3Si_2$ phase shape-modified from ${\beta}-Al_5FeSi$ phase with low Fe/Mn ratio of the alloy.

• 마이크로전자및패키징학회지
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• 제6권4호
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• pp.55-59
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• 1999

전자 패키징에 적용 가능한 납성분이 포함되어 있지 않는 Bi계저융점유리의 연구를 행하였다. Bi계유리중, 70wt% $Bi_2O_3$+ l5wt% $B_2O_3$ + 8wt% $SiO_2$+ 2wt% $P_2O_5$ + 4wt% $A1_2O_3$ + lwt%ZnO 성분의 유리는 융점이 약 $550^{\circ}C$ 였으며, $P_2O_5$의 함량에 따라서 그 융점이 변화하였다. 10wt%이상의 $P_2O_5$ 첨가에서는 $450^{\circ}C$의 열처리로 결정화가 진행되었다. $B_2O_3$가 많이 함유된 조성의 유리에서는 그 융점이 상승하였다.

• 대한금속재료학회지
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• 제50권10호
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• pp.769-774
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• 2012

Mg-x wt% $Fe_2O_3-y$ wt% Ni samples were prepared by reactive mechanical grinding in a planetary ball mill, and their hydrogen-storage properties were investigated and compared. Activations of $Mg-5Fe_2O_3-5Ni$ was completed after one hydriding (under 12 bar $H_2$) - dehydriding (in vacuum) cycle at 593 K. At n = 2, $Mg-5Fe_2O_3-5Ni$ absorbed 3.43 wt% H for 5 min, 3.57 wt% H for 10 min, 3.76 wt% H for 20 min, and 3.98 wt% H for 60 min. Activated $Mg-10Fe_2O_3$ had the highest hydriding rate, absorbing 2.99 wt% H for 2.5 min, 4.86 wt% H for 10 min, and 5.54 wt% H for 60 min at 593 K under 12 bar $H_2$. Activated $Mg-10Fe_2O_3-5Ni$ had the highest dehydriding rate, desorbing 1.31 wt% H for 10 min, 2.91 wt% H for 30 min, and 3.83 wt% H for 60 min at 593 K under 1.0 bar $H_2$.