• 전기학회논문지
• /
• 제61권2호
• /
• pp.243-250
• /
• 2012

In this study, we attempted to reduce firing voltage of AC-PDP by alloying MgO protective Layer with CaO. Also, spray coating of single crystal MgO powder has been used to improving Exo-electron emission characteristics and reducing the statistical discharge delay in plasma displays. The properties of discharge depending upon the single crystal MgO powder are investigated. Plasma display having powder coated MgCaO Protective Layer shows lower driving voltage and higher efficacy than of uncoated, conventional panel.

• Transactions on Electrical and Electronic Materials
• /
• 제1권4호
• /
• pp.11-15
• /
• 2000

This paper presents a process optimization of antireflection (AR) coating on crystalline Si solar cells. Theoretical and experimental investigations were performed on a double-layer AR(DLAR) coating of MgFe$_2$/GeO$_2$. We investigated GeO$_2$ films as an AR layer because they have a proper refractive index of 2.46 and demonstrate the same lattice constant as Si substrate. RF sputter grown GeO$_2$ film showed deposition temperature strong dependence. The GeO$_2$ at 400$\^{C}$ exhibited a strong (111) preferred orientation and the lowest surface roughness of 6.87 $\AA$. Refractive index of MgFe$_2$film was measured as 1.386 for the most of growth temperature. An optimized DLAR coating showed a reflectance as low as 2.04% in the wavelengths ranged from 0.4 ㎛ to 1.1 ㎛. Solar cells with a structure of MgFe$_2$/GeO$_2$/Ag/N$\^$+//p-type Si/P$\^$+//Al were investigated with the without DLAR coatings. We achieved the efficiency of solar cells greater than 15% with 3.12% improvement with DLAR coatings. Further details about MgFe$_2$,GeO$_2$ films, and cell fabrication parameters are presented in this paper.

• 한국수소및신에너지학회논문집
• /
• 제21권6호
• /
• pp.500-506
• /
• 2010

The metal monolith catalyst coated with 15wt% Ni/$MgAl_2O_4$ is applied to the natural gas steam reforming for hydrogen production. To address the improvement of adherence between metal monolith and catalyst coating layer, the pre-calcination temperature as well as the coating conditions of $Al_2O_3$ sol are optimized. When the Fe-Cr alloy monolith is pre-calcined at $900^{\circ}C$ for 6 h, $Al_2O_3$ layer was formed uniformly on the entire surface of the metal substrate. It is seen that the formation of $Al_2O_3$ layer on the monolith surface is essential for the uniform coating of $Al_2O_3$ sol onto the monolith substrate. The monolith catalyst coated with 10wt% $Al_2O_3$ sol shows high $CH_4$ conversion and good thermal stability as compared with the monolith catalyst without $Al_2O_3$ sol coating under severe reaction conditions with high GHSV of 30,000 $h^{-1}$ at $700^{\circ}C$. In addition, the metal monolith catalyst shows higher catalytic activity and better thermal conductivity than 15wt% Ni/$MgAl_2O_4$ pellet catalyst.

• 한국산학기술학회논문지
• /
• 제13권10호
• /
• pp.4365-4370
• /
• 2012

MAO 법을 이용하여 전류밀도 4A/$cm^2$조건에서 3종류의 전해액과 코팅시간에 따라 AZ31 마그네슘 합금을 산화피막 처리하였다. 코팅시간이 길어짐에 따라 코팅층의 표면형상은 기공이 더욱 커지고, 표면에 균열이 발생하기도 하였다. 또한 코팅시간이 길어짐에 따라 코팅층의 두께와 경도(HV)값은 증가하였다. AZ31합금의 코팅층 상들은 MgO, $Mg_2SiO_4$ 그리고 $MgAl_2O_4$ 산화물로 이루어졌다. 산화코팅된 AZ31합금을 5% NaCl 용액에서 168시간동안 염수분무실험결과 우수한 내식성을 나타냈다.

• Corrosion Science and Technology
• /
• 제20권4호
• /
• pp.196-203
• /
• 2021

To improve corrosion resistance and reduce the hydrogen uptake of 22MnB5, up to 5% Mg was added to the AlSi coating of 22MnB5. After hot-stamping and electrocoating were done on the metallic-coated specimen, the surface characteristics of the steel, hydrogen uptake content, and corrosion resistance were examined by transmittance electron microscopy, thermal desorption spectrometry, cyclic corrosion testing, and electrochemical impedance spectroscopy. Mg was investigated as MgO on the surface layer after hot-stamping while it existed as Mg₂Si before hot-stamping. The total hydrogen content of 22MnB5 was decreased along with the Mg content. However, there was no difference at 0.2 wt% or more. When a small amount of Mg was added, the coating corrosion resistance was decreased, but when it was added at around 1.0 wt%, the greatest corrosion resistance increase was seen. However, when 3 wt% or more was added excessively, the corrosion resistance was decreased. MgO on the surface was considered to suppress H uptake by the AlSi melting solution and increase the barrier effect of the coating.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 하계학술대회 논문집
• /
• pp.251-254
• /
• 2001

This paper describes an efficiency improvement of buried contact solar cell (BSCS) with a structure of MgF$_2$/CeO$_2$/Ag/Cu/Ni grid/n$^{+}$ emitter/p-type Si base/p$^{+}$/Al. Theoretical and experimental investigations were performed on a double layer antireflection (DLAR) coating of MgF$_2$/CeO$_2$. We investigated CeO$_2$ films as an AR layer because they have a proper refractive index of 2.46 and demonstrate the same lattice constant as Si substrate. An optimized DLAR coating shewed a reflectance as low as 2.04 % in the wavelengths ranged from 0.4 ${\mu}{\textrm}{m}$ to 1.1 ${\mu}{\textrm}{m}$. BCSC cell efficiency was improved from 16.2 % without any AR coating to 19.9 % by employing DLAR coatings. Further details on MgF$_2$/CeO$_2$ DLAR coatings on the BCSC cells are presented in this paper.per.

• Corrosion Science and Technology
• /
• 제17권1호
• /
• pp.1-5
• /
• 2018

As structural materials, magnesium (Mg) alloys have been widely used in the fields of aviation, automobiles, optical instruments, and electronic products. There are few studies on the effect of coating conditions on the compositional variation during the formation process of the conversion coatings. Rare-earth based conversion coating on AZ91 magnesium alloy was prepared in ceric sulfate and hydrogen peroxide contained solution. The element composition and valence as well as their distribution in the coating were analyzed with energy dispersive X-ray spectroscopy (EDS), Electron probe micro-analyzer (EPMA), X-ray photoelectron spectroscopy (XPS). The effect of treating process on the element composition were also studied. It was found that the conversion coating surface consists of Mg, Al, O, Ce, and the weight content of Ce in the coating was affected by the treating solution concentration and immersion time; the Ce element was distributed in the coating non-uniformly and existed in the form of $Ce^{+3}$ and $Ce^{+4}$, while the O element existed in the form of $OH^-$, $O^{2-}$, $H_2O$. Based on microscopic analysis results, the electrochemical deposition mechanism on the micro-anode and micro-cathode in the process of the coating growth was suggested.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1999년도 추계학술대회 논문집
• /
• pp.590-593
• /
• 1999

$Y_2SiO_5$:Ce was considered as blue phosphor for field emission display because it had an excellent resistance against brightness saturation. But unfortunately It hadn't a sufficient brightness to be applied to FED. In this experiment It-$In_2O_3$, MgO and $SiO_2$ were coated onto $Y_2SiO_5$:Ce phosphor in order to improve the cathodoluminance(CL properties. The coating structures were identified to be the crystalline phases of $In_2O_3$ and MgO respectively. They had fine particle-like shape and were distributed on the surface of $Y_2SiO_5$:Ce phosphor. It was found that the CL efficiency of $Y_2SiO_5$:Ce phosphors were decreased after coatings with In20:j and MgO in voltage range from 500 V to 5 kV. But the brightness of $Y_2SiO_5$:Ce phosphor was increased after coating of 5 0 2 . And also the aging test showed that $In_2O_3$ coating improved the life time of $Y_2SiO_5$:Ce phosphor.

• 전자공학회논문지
• /
• 제52권5호
• /
• pp.206-213
• /
• 2015

함정용 전자광학추적장비의 센서부에서 해수면반사파에 의해 발생하게 되는 영상추적간섭 현상을 최소화하고자 전방향성, 점진적인 굴절률 및 표면 요철구조를 갖는 산화아연에 플루오르화마그네슘을 코팅한 반사방지막을 전자빔 증착 장비를 통해 제작하였다. 최적화된 산화아연에 플루오르화마그네슘을 코팅한 반사방지막은 기존의 산화아연 반사방지막과 비교하여 점진적인 굴절률 변화에 따라 표면 프레넬 반사를 최소화하고 이를 통해 전자광학추적장비의 영상추적간섭 현상을 제거하는 장점이 있다. 본 실험을 통해, 산화아연에 플루오르화마그네슘을 코팅한 반사방지막이 다양한 전자광학장비의 반사방지막으로써 적용이 가능함을 확인하였다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
• /
• pp.373-373
• /
• 2011

$Cu(In,Ga)Se_2$(CIGS) 박막 태양전지는 Chalcopyrite계 박막 태양전지로 Cu, In, Ga, Se 각 원소의 조성을 적절히 조절하여 박막을 성장시킨다. 성장시킨 CIGS 박막은 광흡수계수가 105cm-1로 다른 물질 보다 뛰어나고 직접 천이형 반도체로서 얇은 두께로도 고효율의 박막 제작이 가능하다. 얇은 두께로도 충분히 빛의 흡수가 가능하지만, cell 표면 반사에 의한 광 손실은 cell 효율을 떨어뜨리게 된다. 본 연구에서는 CIGS 박막 태양전지의 광 흡수 향상을 위해 굴절률이 1.86인 ITO 위에 ITO보다 굴절률이 작은 $MgF_2$ (n=1.377) [1]를 80, 100, 120, 140 nm로 증착하여 $MgF_2$/Al/Ni/ITO/i-ZnO/CdS/CIGS/Mo/SLG 시료를 제작하고, optical reflectance, Quantum Efficiency를 이용하여 분석하였다. optical reflectance 분석 결과, $MgF_2$ AR coating을 한 경우, 두께가 두꺼워짐에 따라 광 반사도가 감소하는 경향을 보였다. 또한 AR coating 두께가 커짐에 따라 fluctuation이 점점 커지며, 파형이 장파장 쪽으로 shift하는 것을 관찰 할 수 있었다. Quantum efficiency (QE)를 분석한 결과 $MgF_2$ AR coating 할 경우, 측정된 대부분의 파장에서 QE가 향상되는 것을 확인할 수 있었다. 하지만 AR coating 두께에 따른 변화는 뚜렷한 차이를 보이지 않았다. AR coating 결과, JSC가 증가하여 efficiency가 향상되는 것을 확인 할 수 있다. 그러나 $MgF_2$ AR coating 80~140 nm 범위에서 cell 효율 변화의 뚜렷한 차이는 관찰할 수 없었다.