• Korean Chemical Engineering Research
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• 제54권2호
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• pp.175-180
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• 2016

본 연구에서는 내 오존성을 향상시키기 위해 PFPE-diol을 도입하여 불소계 변성 폴리우레아를 합성하였다. 불소 함량에 따라 변성 폴리 우레아(PFDIA-10C, PFDIA-20C, PFDIA-30C)를 제조하였으며 각각의 폴리우레아는 불소를 10 wt%~30 wt% 포함하였다. 제조된 도막의 오존처리 전 후 질량변화를 조사하였고, 도막의 경도, 내마모성, 인장성능 그리고 신장율 등의 물성을 분석하였다. 또한 내 오존성 테스트(10 ppm, 336 h)후에 광학현미경을 통해 도막표면을 관찰한 결과 PFPE-diol의 함량이 20 wt% 이상 일 때 균열, 탈색 그리고 질량감소량에서 양호한 결과를 보여주어 도막의 내 오존성이 향상되었음을 알 수 있었다. FT-IR 분석을 통해 PFDIA 합성물의 O-H 피크가 불소 함량 증가함에 따라 감소하는 것을 확인하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제32권4호
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• pp.527-532
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• 2019

Objective: Phosphorous (P) sources with greater bioavailability might increase animal production efficiency and decrease environmental pollution. The objective of current study was to determine animal performance, nutrient digestibility, blood metabolites and fecal P concentration in finishing lambs fed a diet with either di-calcium phosphate (DCP) or di-ammonium phosphate (DAP) as a P source. Methods: Twelve 4-month-old male lambs (initial body weight $24.87{\pm}3.4kg$) were randomly allocated to a diet with either DCP or DAP (~261 g/kg of total diet P) fed ad libitum for 93 days. Diets were iso-nitrogenous and iso-energetic and had same calcium (Ca) and P concentrations. Results: The DAP contained 19.7 g/kg of dry matter (DM) Ca, 185.4 g/kg DM P and 14,623 ppm fluorine, while DCP contained 230.3 g/kg DM Ca, 195.2 g/kg DM P and 1,039 ppm fluorine. The diet with DAP contained 60 ppm fluorine while the diet with DCP contained 13 ppm fluorine. Lambs fed the diet with DAP tended to have a greater daily DM intake compared to those fed diet with DCP (p = 0.09). Lambs fed DAP had greater plasma P concentration and alkaline phosphatase activity ($p{\leq}0.01$) compared with lambs fed DCP. Dry matter and organic matter digestibility of the diets were similar between two treatments at days 60 and 90, while they were greater in lambs fed DCP (p<0.05) at day 30 of the trial. Feeding DAP increased P digestibility (58.7% vs 50.2%; p<0.05) and decreased fecal P concentration in lambs compared with feeding DCP (3.1 vs 3.8 g/kg DM; p<0.05). Conclusion: Providing ~261 g/kg of total diet P as DAP in the diet of finishing lambs improved the bioavailability of P in the body and decreased excretion of P in feces without affecting lamb performance.

• 한국재료학회지
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• 제31권3호
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• pp.150-155
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• 2021

Zinc oxide (ZnO) based transparent conducting oxides (TCO) thin films, are used in many applications such as solar cells, flat panel displays, and LEDs due to their wide bandgap nature and excellent electrical properties. In the present work, fluorine and aluminium-doped ZnO targets are prepared and thin films are deposited on soda-lime glass substrate using a RF magnetron sputtering unit. The aluminium concentration is fixed at 2 wt%, and the fluorine concentration is adjusted between 0 to 2.0 wt% with five different concentrations, namely, Al2ZnO98(AZO), F0.5AZO97.5(FAZO1), F1AZO97(FAZO2), F1.5AZO96.5(FAZO3), and F2AZO96(FAZO4). Thin films are deposited with an RF power of 40 W and working pressure of 5 m Torr at 270 ℃. The morphological analysis performed for the thin film reveals that surface roughness decreases in FAZO1 and FAZO2 samples when doped with a small amount of fluorine. Further, optical and electrical properties measured for FAZO1 sample show average optical transmissions of over 89 % in the visible region and 82.5 % in the infrared region, followed by low resistivity and sheet resistance of 3.59 × 10-4 Ωcm and 5.52 Ω/sq, respectively. In future, these thin films with excellent optoelectronic properties can be used for thin-film solar cell and other optoelectronics applications.

• 한국재료학회지
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• 제33권4호
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• pp.124-129
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• 2023

This study assessed the influences of fluorine introduced into DLC films on the structural and mechanical properties of the sample. In addition, the effects of the fluorine incorporation on the compressive stress in DLC films were investigated. For this purpose, fluorinated diamond-like carbon (F-DLC) films were deposited on cobalt-chromium-molybdenum substrates using radio-frequency plasma-enhanced chemical vapor. The coatings were examined by Raman scattering (RS), Attenuated total reflectance Fourier transform infrared spectroscopic analysis (ATR-FTIR), and a combination of elastic recoil detection analysis and Rutherford backscattering (ERDA-RBS). Nano-indentation tests were performed to measure hardness. Also, the residual stress of the films was calculated by the Stony equation. The ATR-FTIR analysis revealed that F was present in the amorphous matrix mainly as C-F and C-F₂ groups. Based on Raman spectroscopy results, it was determined that F made the DLC films more graphitic. Additionally, it was shown that adding F into the DLC coating resulted in weaker mechanical properties and the F-DLC coating exhibited lower stress than DLC films. These effects were attributed to the replacement of strong C = C by feebler C-F bonds in the F-DLC films. F-doping decreased the hardness of the DLC from 11.5 to 8.8 GPa. In addition, with F addition, the compressive stress of the DLC sample decreased from 1 to 0.7 GPa.

• 유기물자원화
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• 제31권2호
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• pp.5-18
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• 2023

국내 불소계 화학물질의 배출현황 조사결과 Hydrogen fluoride(91%)와 Perfluorocarbons(5%) 등 13종의 물질이 사업장을 통해 배출되었고, 지역별로는 경북, 경기, 충청권 지역에서 약 98%, 업종별로는 전자부품, 화학물질, 비금속 광물제품 제조업 관련 3개 분야에서 약 98%를 배출하였다. 주요 수계에서 나타나는 PFOS·PFOA의 검출 현황은 불소계 화학물질 배출량이 많은 낙동강 수계, 금강 수계, 안성천 하구언 지점에서 지속 검출되었으며, 4개의 PFOS 지점과 2개의 PFOA 지점은 2021년 처음으로 검출되었다. 반도체와 디스플레이 관련 업종이 많은 수계 지역에서 PFOS 및 PFOA가 비교적 높은 농도로 지속 검출되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1019-1021
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• 1995

Light induced degradation of hydrogenated amorphous silicon(a-Si:H) are related to the number of weak dangling bonds which are thought to be responsible for the Staebler-Wronski effects, and caused the many photoelectric problems in applications of thin film transistors and solar cell, etc. In this paper, we deposited fluorinated amorphous silicon films(a-Si:H;F) with $SiH_4$ and $SiF_4$ gas mixture and investigated the effects of fluorine atoms on the evoluations of the crystallinity and improvements of light instability. We have found that micro-crystallinity produced in a-SI:H;F films and marked maximum value of 22% at the flow rate of $SiH_4:SiF_4$=2:10 sccm by UV spectrophotometer measurement, while n-Si:H film deposited with only $SiH_4$ gas showed no crystallinity. Light-induced degradation property of a-Si:H;F films is also improved which is mainly due to the etching effects of fluorine atoms on the weak Si-Si bonds and unstable hydrogen bonds. It is considered that involving fluorine atoms in a-Si:H films may contribute to the suppression of light-induced degradation and evolution of micro-crystallinity.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.349-350
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• 2002

The friction and wear behaviors of fluorine-containing compounds such as perfluoropolyethers (PFPE), phosphazenes (X-1P), ionic liquids as lubricants for steel/seel, steel/ceramic, ceramic/ceramic were investigated using a SRV tester and a one-way reciprocating friction tester both in ball-on-disc configuration. It was found that the three fluorine-containing lubricants could reduce friction coefficient and wear volume effectively. The effectiveness of the three lubricants in reducing wear volume could be ranked as ionic liquids>X-1P>PFPE. Tests also showed that aryloxyphosphazene with polar substituent as a lubricant of steel/steel pair gave low wear, while aryloxyphosphazene with nonpolar group on the phenyl pendant led to high wear. The morphology and the tribo-chemical reaction of the worn surfaces were analyzed with a scanning electron microscope (SEM) and X-ray photoelectron spectroscope (XPS). XPS analyses illustrated the formation of iron fluoride in steel/steel system with the lubrication of both phosphazenes and ionic liquids.

• ETRI Journal
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• 제21권3호
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• pp.16-21
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• 1999

After etching Al-Cu alloy films using SiCl4/Cl_2/He/CHF3 mixed gas plasma, the corrosion phenomenon at the grain boundary of the etched surface and a passivation layer on the etched surface with an SF6 plasma treatment subsequent to the etching were studied. In Al-Cu alloy system, corrosion occurs rapidly on the etched surface by residual chlorine atoms, and it occurs dominantly at the grain boundaries rather than the crystalline surfaces. To prevent corrosion, the SF6 gas plasma treatment subsequent to etching was carried out. The passivation layer is composed of fluorine-related compounds on the etched Al-Cu surface after the SF6 treatment, and it suppresses effectively corrosion on the surface as the SF6 treatment pressure increases. Corrosion could be suppressed successfully with the SF6 treatment at a total pressure of 300 mTorr. To investigate the reason why corrosion could be suppressed with the SF6 treatment, behaviors of chlorine and fluorine were studied by various analysis techniques. It was also found that the residual chlorine incorporated at the grain boundary of the etched surface accelerated corrosion and could not be removed after the SF6 plasma treatment.

• 한국결정성장학회지
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• 제19권4호
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• pp.190-195
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• 2009

스컬용융법에 의해 Na사규소운모를 합성하였다. $Mg_3(OH)_2Si_4O_{10}:Na_2SiF_6:SiO_2=8.3:24.8:66.9$ mol% 비율로 혼합한 출발원료를 ${\phi}13{\times}H14cm$의 냉각도가니에 채우고 2.84MHz 출력주파수의 고주파발진기를 이용하여 가열하였다. 원료는 융액상태에서 1시간 유지하였으며 도가니 내에서 냉각시켰다. 운모의 비저항은 추정하였으며, 원주모양과 판상으로 합성할 수 있었다.

• 한국세라믹학회지
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• 제27권7호
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• pp.925-933
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• 1990

The possible use of bioglass,, which is one of the surface active biomaterials, as implants materials has drawn great attention due to their ability to bond to human living tissue. In the present work, the investigation was carried out to find the bonding phenomena between alumina substrate and bioglass(45S5) or fluorine-containing bioglass(45S5$.$4F), and the properties of coated bioglass. The stable bonding between alumina and bioglass was formed when heat-treated at 1150$^{\circ}C$ for 120 minutes or at 1250$^{\circ}C$ for 30 minutes for the 45S5, and at 1150$^{\circ}C$ for 30 minutes for the 45S5$.$4F. When bioglass coated alumina was heat-treated, great amount of Al was diffused into bioglass from alumina substrate. More Al was diffused into fluorine-containing bioglass than into bioglass without fluorine. At early stage of heat-tretment, the diffused alumina content was increased with the square root of time and it was also increased with the thickness of coating layer and heat-treatment temperatures. The alumina content became constant after its saturation for longer heat-treatment time. Coated bioglasses were crystallized to Na2O$.$CaO$.$3SiO2 when heat-treated at lower temperature, and to CaO$.$SiO2 at higher temperature.