• 한국결정성장학회지
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• 제16권2호
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• pp.59-65
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• 2006

Al이 첨가된 ZnO(ZnO : Al) 박막과 F이 첨가된 ZnO(ZnO : F) 박막을 sol-gel 법을 이용하여 glass 기판위에 코팅하였다. 공통적으로 (002)면의 c-축 배향성을 보였지만 I(002)/[I(002) + I(101)]와 FWHM(full width at half-maximum) 값은 차이를 보였다. 특히 입자크기에 있어서는 ZnO : Al 박막에서 첨가농도가 증가함에 따라 입자크기가 감소한 반면 ZnO : F 박막에서는 F 3 at%까지 입자크기가 증가하다가 그 이후로 다시 감소하는 경향을 보였다. 진기적 성질의 측정을 위해서 Hall effect measurement를 이용하였는데 ZnO : Al 박막의 경우 Al 1 at%에서 비저항이 $2.9{\times}10^{-2}{\Omega}cm$ 이었고 ZnO : F에서는 F 3 at%에서 $3.3{\times}10^{-1}{\Omega}cm$의 값을 보였다. 또한 ZnO : F 박막은 ZnO : Al 박막에 비해서 캐리어 농도는 낮았지만(ZnO : Al $4.8{\times}10^{18}cm^{-3}$, ZnO : F $3.9{\times}10^{16}cm^{-3}$) 이동도에 있어서 상당히 큰 값(ZnO : Al $45cm^2/Vs$ ZnO:F $495cm^2/Vs$)을 보였다. 가시광선 영역에서의 평균 광투과도에 있어서는 ZnO : Al 박막에서 $86{\sim}90%$의 값을 보였지만 ZnO : F에서는 $77{\sim}85%$로 상대적으로 낮은 광투과도를 나타내었다.

• 한국세라믹학회지
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• 제39권3호
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• pp.315-320
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• 2002

저농도로 희석된 HF 수용액(6 wt%)을 사용하여 $Al(OH)_3$의 표면을 F/Al의 몰비 0.15에서 처리하고, 처리 전후 표면특성을 관찰하였다. 반응계의 온도 및 pH 변화로부터 $Al(OH)_3$에 대한 HF의 표면반응은 HF와 접촉한 $Al(OH)_3$ 표면부에서 metastable한 ${\alpha}$형의 불화알루미늄$({\alpha}-AlF_3{\cdot}3H_2O)$이 안정한 ${\beta}$형의 불화알루미늄$({\beta}-AlF_3{\cdot}3H_2O)$으로 전이되는 과정으로 진행되며, 다량의 발열을 수반하면서 반응계의 온도상승을 유발하였다. 이러한 ${\beta}-AlF_3{\cdot}3H_2O$의 생성은 표면처리된 분말의 FT-IR 및 X-선 회절분석결과를 통해 확인되었다. ${\beta}-AlF_3{\cdot}3H_2O$의 morphology와 분포상태를 SEM을 통해 관찰한 결과 $Al(OH)_3$ 표면에 $1{\mu}m$ 이하의 미세분말 형태로 피복층을 형성하며 균일하게 분포된 것으로 확인되었다. HF로 처리된 시료의 표면 백색도는 미처리에 비해 약 6.6% 증가되었으며, 이는 $Al(OH)_3$보다 높은 백색도를 지닌 ${\beta}-AlF_3{\cdot}3H_2O$ 피복 효과 때문인 것으로 나타났다.

• 한국전기전자재료학회논문지
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• 제21권7호
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• pp.665-668
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• 2008

Multi-layered thin films of $Fe_2O_3/Na_3AlF_6/Fe_2O_3/Cu$, Cr, Al were deposited on glass substrate by evaporation process. As high and low refractive index material, $Fe_2O_3$ and $Na_3AlF_6$ were selected and additionally Cu, Al and Cr were chosen as mid reflective layer respectively. Optical properties including reflectance were systematically studied depending on optical thickness of $Na_3AlF_6$ especially $0.25{\lambda}$ and $0.5{\lambda}$. In order to expect the experimental result, the simulation program, the Essential Macleod Program(EMP) was adopted and compared with the experimental data. Based on the results taken by spectrophotometer at viewing angle $45^{\circ}C$, the $Fe_2O_3/Na_3AlF_6/Fe_2O_3/Cu$ show the colour rage between red and orange in $0.25{\lambda}$ and green and pupple in $0.5{\lambda}$ respectively. When the Al was used as mid reflective layers in $Fe_2O_3/Na_3AlF_6/Fe_2O_3$ system, typical yellow colour and mixed colour between green and pupple were appeared in $0.25{\lambda}$ and $0.5{\lambda}$ of $Na_3AlF_6$ respectively. As compared the experimental result to simulation data, it was found out that the experimental data is relatively well matched with the EMP simulation data.

• 한국세라믹학회지
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• 제43권10호
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• pp.595-600
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• 2006

The preparation of $\beta$-SiAlON powder by SHS in the system of $Si-Al-SiO_2-NH_4F(\beta-Si_3N_4)$ was investigated in this study. In the preparation of SiAlON powder, the effect of gas pressure, compositions such as Si, $NH_4F$, \beta-Si_3N_4$ and additive in mixture on the reactivity were investigated. At 50 atm of the initial inert gas pressure in reactor, the optimum composition for the preparation of pure $\beta$-SiAlON was $3Si+Al+2SiO_2+NH_4F$. The $\beta$-SiAlON powder synthesized in this condition was a single phase $\beta$-SiAlON with a rod like morphology.

• 한국세라믹학회지
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• 제28권8호
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• pp.647-653
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• 1991

In order to synthesize fine AlN powder by the direct nitridation of Aluminum metal power added LiF and BaF2 as additives was heated at 150$0^{\circ}C$ for 3 hrs. in nitrogen gas with flow rate of 20 mι/sec. Additives are promoted the nitridation by prevented the aggromerate of powders when 3% LiF and 2% BaF2 were added to Al metal powder. Rate of nitridation was about 100% and average size of AlN powders were very fine such as 0.3 ${\mu}{\textrm}{m}$. Specific surface area of synthesized AlN powder was 3.95$m^2$/g and also O2 and N2 contents were 2.595% and 33.25%, respectively.

• 한국재료학회지
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• 제9권6호
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• pp.630-634
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• 1999

$Al(OH)_3$와 비정질 $SiO_2$를 출발원료로 사용하여 반응소결을 통한 다공성 뮬라이트를 제조하였다. $Al(OH)_3$와 $SiO_2$의 몰비를 뮬라이트의 화학양론적 조성과 실리카와 얄루미나가 많은 조성으로 변화시키고, 각 조성에 $AlF_3$를 0, 1, 5, 10wt% 첨가하여 뮬라이트의 생성에 미치는 조성과 첨가제의 영향을 살펴보았다. 첨가한 $AlF_3$의 양이 많아질수록 낮은 온도에서 뮬라이트가 생성됨을 보였고, 첨가된 $AlF_3$의 양이 5wt%인 경우, 화학량론적 뮬라이트 조성에서 율라이트가 $1250^{\circ}C$에서부터 생성되기 시작하였으 며 $1300^{\circ}C$ 이상 열처리한 경우 충분히 발달한 침상형의 다공성 뮬라이트가 합성되었다. $AlF_3$의 양이 5wt% 이상 첨가한 경우 열 처리 온도의 영향은 크게 나타나지 않았으며, 소성체의 수축도 거의 일어냐지 않았다.

• 공업화학
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• 제9권3호
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• pp.372-376
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• 1998

Pd를 지지체에 담지시킨 촉매($Pd/AlF_3$, $Pd/{\gamma}-Al_2O_3$)와 고체산촉매(${\gamma}-Al_2O_3$, ${\alpha}-Al_2O_3$, $AlF_3$)를 제조한 후 수소분위기에서 HCFC-142b(1-chloro-1,1-difluoroethane)의 탈염소반응을 수행하여 반응온도, 수소/HCFC-142b의 공급비(r) 및 Pd담지량 변화가 HFC-143a(1,1,1-trifluoroethane)와 HFC-152a(1,1-difluoroethane)로의 선택도에 미치는 영향을 조사하였다. 실험결과 $Pd/AlF_3$와 $Pd/{\gamma}-Al_2O_3$촉매에 의한 전환율은 각각 60%와 92%였고, 생성가스 중에서 HFC-143a로의 선택도는 각각 58%와 64%였다. 이때 최적반응조건은 반응온도, $200^{\circ}C$, 공간시간 1.05s, 수소/HCFC-142b의 공급비가 3이었다. 한편, 동일 조건하에서 ${\gamma}-Al_2O_3$와 ${\alpha}-Al_2O_3$, 그리고 $AlF_3$촉매에 의한 HCFC-142b의 생성가스로의 전환율은 각각 12%, 8%와 7%였고, 생성가스중 HFC-152a로의 선택도는 각각 94%, 92%와 90%였다.

• 한국재료학회지
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• 제21권12호
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• pp.644-649
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• 2011

[ $A_{3-2x/3}Al_{1-z}In_{z}O_4F:Eu_x^{3+}$ ](A = Ca, Sr, Ba, x = -0.15, z = 0, 0.1) oxyfluoride phosphors were simply prepared by the solid-state method at $1050^{\circ}C$ in air. The phosphors had the bright red photoluminescence (PL) spectra of an $A_{3-2x/3}Al_{1-z}In_{z}O_4F$ for $Eu^{3+}$ activator. X-ray diffraction (XRD) patterns of the obtained red phosphors were exhibited for indexing peak positions and calculating unit-cell parameters. Dynamic excitation and emission spectra of $Eu^{3+}$ activated red oxyfluoride phosphors were clearly monitored. Red and blue shifts gradually occurred in the emission spectra of $Eu^{3+}$ activated $A_3AlO_4F$ oxyfluoride phosphors when $Sr^{2+}$ by $Ca^{2+}$ and $Ba^{2+}$ ions were substituted, respectively. The concentration quenching as a function of $Eu^{3+}$ contents in $A_{3-2x/3}AlO_4F:Eu^{3+}$ (A = Ca, Sr, Ba) was measured. The interesting behaviors of defect-induced $A_{3-2x/3}Al_{1-z}In_{z}O_{4-{\alpha}}F_{1-{\delta}}$ phosphors with $Eu^{3+}$ activator are discussed based on PL spectra and CIE coordinates. Substituting $In^{3+}$ into the $Al^{3+}$ position in the $A_{3-2x/3}AlO_4F:Eu^{3+}$ oxyfluorides resulted in the relative intensity of the red emitted phosphors noticeably increasing by seven times.

• Toxicological Research
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• 제14권2호
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• pp.163-169
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• 1998

Fluoride (F), over a narrow concentration range, increases bone formation. Aluminum (Ai) too is biphasic in its action on bone, being mitogenic at very low levels and inhibitory at higher levels. Both F and Al are present in finished drinking water where the chemical interaction of these two agents is well characterized. F and AI, given individually, accumulate preferentially in bone. In addition. in vivo studies have shown that F causes the co-accumulation of Al in bone. Thus, it was necessary to determine the interactive effect of these two agents on bone mitogenesis. Calvaria were obtained from neonatal CD-1 mice and cultured with various concentrations of F (0.05~19 ppm) as NaF, Al (2 ppb~2 ppm) as $AlCl_3$ , or F and Al for 3 days at $37^{\circ}C$ on a rotating roller drum. Alkaline phosphatase activity in calvaria and $\beta$-glucuronidase activity in culture medium were determined as a measures of bone turnover. Alkaline phosphatase activity in calvaria was significantly increased by F (0.05~2 ppm) treatment and $\beta$-glucuronidase activity was slightly increased in the culture medium of calvaria treated with 0.3 ppm Al. The combination of 19 ppm F and 0.3 ppm Al increased alkaline phosphatase activity in calvaria, but did not affect $\beta$-glucuronidase activity, suggesting the interactive effect of fluoride and aluminum on bone turnover.

• 한국재료학회지
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• 제21권11호
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• pp.604-610
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• 2011

The effect of $BaF_2$ flux in $Y_3Al_5O_{12}:Ce^{3+}$(YAG:Ce) formation was investigated. Phase transformation of $Y_3Al_5O_{12}$(YAG) was characterized by using XRD, SEM, and TEM-EDS, and it was revealed that the sequential formation of the $Y_4Al_2O_9$(YAM), $YAlO_3$(YAP) and $Y_3Al_5O_{12}$(YAG) in the temperature range of 1000-1500$^{\circ}C$. Single phase of YAG was revealed from 1300$^{\circ}C$. In order to find out the effect of $BaF_2$ flux, three modeling experiments between starting materials (1.5$Al_2O_3$-2.5$Y_2O_3$, $Y_2O_3$-$BaF_2$, and $Al_2O_3$-$BaF_2$) were done. These modeling experiments showed that the nucleation process occurs via the dissolution-precipitation mechanism, whereas the grain growth process is controlled via the liquid-phase diffusion route. YAG:Ce phosphor particles prepared using a proposed technique exhibit a spherical shape, high crystallinity, and an emission intensity. According to the experimental results conducted in this investigation, 5% of $BaF_2$ was the best concentration for physical, chemical and optical properties of $Y_3Al_5O_{12}:Ce^{3+}$(YAG:Ce) that is approximately 10-15% greater than that of commercial phosphor powder.