• Resources Recycling
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• v.16 no.3 s.77
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• pp.34-43
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• 2007

A comparative study of the extraction behavior of vanadium and titanium in sulphate solutions using Cyanex272, PC88A and Alamine336 has been carried out. effect of pH in sulphate solutions, concentration of extractant and extraction isotherms has been studied. Solvent extraction separation studies of vanadium and titanium from the mixed solutions were also carried out in order to obtain a criterion for choosing the more effective extraction regent. From the experimental results, it was conformed that Alamine336 was good extractant to extraction of vanadium and separation from titanium from the mixed solutions.

• Korean Journal of Dental Materials
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• v.45 no.4
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• pp.257-274
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• 2018

The purpose of this study was to evaluate the effect of acid-treatment conditions on the surface properties of the RBM (Resorbable Blast Media) treated titanium. Disk typed cp-titanium specimens were prepared and RBM treatments was performed with calcium phosphate ceramic powder. Acid solution was mixed using HCl, $H_2SO_4$ and deionized water with 4 different volume fraction. The RBM treated titanium was acid treated with different acid solutions at 3 different temperatures and for 3 different periods. After acid-treatments, samples were cleaned with 1 % Solujet solution for 30 min and deionized water for 30 min using ultrasonic cleanser, then dried in the electrical oven ($37^{\circ}C$). Weight of samples before and after acid-treatment were measured using electric balance. Surface roughness was estimated using a confocal laser scanning microscopy, crystal phase in the surface of sample was analyzed using X-ray diffractometer. Surface morphology and components were evaluated using Scanning Electron Microscope (SEM) with Energy Dispersive X-ray spectroscopy (EDX) and X-ray Photoemission Spectroscopy (XPS). Values of the weight changes and surface roughness were statistically analyzed using Tukey-multiple comparison test (p=0.05). Weight change after acid treatments were significantly increased with increasing the concentration of $H_2SO_4$ and temperature of acid-solution. Acid-treatment conditions (concentration of $H_2SO_4$, temperature and time) did not produce consistent effects on the surface roughness, it showed the scattered results. From XRD analysis, formation of titanium hydrides in the titanium surface were observed in all specimens treated with acid-solutions. From XPS analysis, thin titanium oxide layer in the acid-treated specimens could be evaluated. Acid solution with $90^{\circ}C$ showed the strong effect on the titanium surface, it should be treated with caution to avoid the over-etching process.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.151-151
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• 2003

최근 휴대폰용 LCD, 컴퓨터용 TFT LCD, 가정용 PDP 등 평판 디스플레이 산업의 발달에 힘입어 평판 디스플레이 장치의 구동 칩 실장 부품인 TCP(tape carrier package), COF(chip on film) 제조 산업 또한 발전하고 있다. 이들 TCP, COF는 디스플레이 장치의 경박화에 따라 보다 가는 선폭의 회로가 요구되어지는데 이를 위해 회로를 구성하는 기본소재로 얇은 두께의 동박이 사용된다. 회로기판용 동박으로는 압연동박과 전해동박이 함께 사용되어 왔으나 박막의 제조가 어려운 압연동박의 단점과 면에 수직한 주상정 조직이 발달해 있어 일반 압연 동박에 비해 접착력이 뛰어나며 전류밀도 또는 티타늄 음극 드럼 회전 속도를 조절하여 두게 조절이 용이한 전해동박의 장점으로 인해 현재 압연동박의 전해동박으로의 대체가 증가하고 있다. 전해동박의 제조공정은 크게 제박 공정과 후처리 공정으로 나눌 수 있다. 전해동박은 먼저 드럼형태의 티타늄 음극과 불용성 납 양극으로 이루어진 제박기에 고 전류를 가하여 황산구리 용액 중 구리를 티타늄 음극에 석출시킴으로서 구리 원박을 제조한 후 접착력 향상을 위한 노듈 형성, 방식, 방청, 내열성 향상 등을 위한 여러 개의 단위 셀 조합으로 이루어진 후처리 공정을 거쳐 제조된다.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.4
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• pp.71-75
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• 2022

In this research, Fe-Ni alloy films were electrodeposited on stainless steel (SS304 and SS430) and Ti plates to investigate the effects of surface conditions of cathode on deposits. The Ti plates were electropolished in 3 M H₂SO₄-methanol electrolytes at various conditions before electrodeposition, and unpolished Ti and the optimized specimen, polished at 10 V for 8 min, were used as cathode. The anomalous codeposition, the phenomenon which more active Fe is reduced preferentially, occurred on all substrate, however, there were differences in composition of all deposits. As the results of potential monitoring during electrodeposition, it was confirmed that the larger overpotential was applied to the deposition cell when using Ti cathode, leading to high Fe content of deposits from unpolished Ti due to increase in nucleation of Fe. Also, it was founded that the polished Ti can reduced deposition overpotential.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.365-368
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• 2009

메탄올 연료전지에서 기존의 탄소 지지체의 전기화학적인 특성과 유사한 새로운 지지체 물질을 개발하기위해서 $TiO_2$ 산화물을 선정하였고 이것의 전도성을 향상에 관한 연구를 하였다. 새로운 지지체인 Degussa $TiO_2$를 이용하여 고온에서 열처리하는 방법으로써 얻을 수 있었다. 이러한 지지체위에 백금 촉매를 담지하는 합성 실험은 간단한 방법인 sodium borohydride 방법으로써 수행하였고 구조적인 결과를 확인하기 위하여 XRD 분석으로써 확인하였다. 결과로부터 $TiO_2$에서 TiN으로 구조적인 변화를 알 수 있었고 상변화 과정이 높은 에너지와 소스로 인해 바뀐다는 것을 알 수 있었다. 이러한 지지체 촉매 전극의 전기적인 활성을 알아보기 위하여 CVs와 안전성을 확인하기 위하여 CA에서 분석하였다. 기존 탄소 지지체 촉매 전극과 황산과 메탄올 용액하에서 CVs와 CA를 비교하였을 때, 티타늄 질화물 지지체가 CVs에서 유사한 산화, 환원 활성을 나타내었고 CA에서 높은 전류에서 안정성을 보여주었다. 이러한 결과로부터 TiN 지지체는 탄소 지지체와 비교하였을 때 연료전지의 지지체로써의 가능성을 확인 할 수 있었다.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.3
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• pp.339-344
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• 2008

Titanium dioxide nanotubes were fabricated by self-organized electrochemical potentiostatic anodization of titanium thin film with an electrolyte solution of sodium sulfate 1M and sodium flouride 0.5wt% aqueous solution at 20$^{\circ}C$ for 20min. Field Emmision Scanning Electron Microscopy(FE-SEM) and X-ray Diffractometer(XRD) were used to evaluate the micromorphology and crystalline structure of the titanium dioxide nanotube thin film. Titanium dioxide nanotube were fabricated with diameters approx. 100nm and tube length from appox. 1 $\mu$m. Titanium dioxide films formed through anodization and annealing process at 450$^{\circ}C$ contained a phase of anatase. Also, this study was performed to evaluate the application of titanium dioxide thin film for treating humic acid dissolved in water. The reaction tended to follow the Langmuir-Hinshelwood kinetics with zero order. Comparative experiments with thin film and anatase powder showed the same zero order kinetics when 0.3g of powder had been used.

• Resources Recycling
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• v.29 no.5
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• pp.48-54
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• 2020

Sulphuric acid (H₂SO₄) leaching and hydrolysis were experimented for the recovery of titanum dioxide (TiO₂) from the water-leached residue followed by soda-roasting spent SCR catalysts. Sulphuric acid leaching of Ti was carried out with leachate concentration (4~8 M) and the others were fixed (temp.: 70 ℃, leaching time: 3 hrs, slurry density: 100 g/L, stirring speed: 500 rpm). For recovering of Ti from the leaching solution, hydrolysis precipitation was conducted at 100 ℃ for 2 hours in various mixing ratio (leached solution:distilled water) of 1:9 to 5:5. The maximum leachability was reached to 95.2 % in 6 M H₂SO₄ leachate. on the other hand, the leachability of Si decreased dramatically 91.7 to 3.0 % with an increase of H₂SO₄ concentration. Hydrolysis precipitation of Ti was proceeded with leaching solution of 8 M H₂SO₄ with the lowest content of Si. The yield of precipitation increased proportionally with a dilution ratio of leaching solution. Moreover, it increased generally by adding 0.2 g TiO₂ as a precipitation seed to the diluted leaching solution. Ultimately, 99.8 % of TiO₂ can be recovered with the purity of 99.46 % from the 1:9 diluted solution.

• Resources Recycling
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• v.30 no.4
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• pp.27-34
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• 2021

In this study, the leaching behavior of vanadium (V) was investigated through CaO roasting and sulfuric acid leaching from domestic V-bearing titanomagnetite (VTM). Changes in the phase according to the amount of CaO added and roasting temperature were analyzed. Regardless of the roasting conditions, perovskite (CaTiO₃) was preferred to form. When the CaO content was increased, the calcium ferrite (CaFeO_x) phase was formed; otherwise, ferrite (Fe₂O₃) was preferred. After CaO was roasted, leaching was performed for 6 h with 1M sulfuric acid at 50℃ and a 10% solid-liquid ratio. Results of leaching revealed that when the roasted product was sintered, V was not sufficiently oxidized, and the leaching efficiency decreased. In addition, when the roasting temperature was low, the leaching efficiency of V decreased due to the influence of unreacted excess CaO. To lower the leaching efficiency of iron and titanium in VTM concentrates, suppressing the formation of CaTiO₃ and CaFeO_x was necessary by minimizing the amount of CaO added. Consequently, a leaching efficiency of 86% V, 4.3% Fe, and 6.5% Ti was obtained when the roasted product of 1150℃ and 10 wt% CaO was leached.

• Journal of Radiation Protection and Research
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• v.27 no.2
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• pp.95-100
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• 2002

Conventional and modified electrolytic decontamination experiment were performed in the 1.7 M solution of sodium sulfate and sodium nitrate tot decontamination of carbon steel as the simulated metal wastes which have been produced in large amounts from nuclear power plants. Anode ant cathode were used as inconel and titanium respective. The reaction time and temperature were 1 hr and $25^{\circ}C$ The analyses were performed of the characteristics such as weight loss arid thickness change of metal waste. suspended solid in electrolyte and SEM observation. In modified electrolyte decontamination system with increased current density ranged from 0.1 to $0.6A/cm^2$, the metal waste showed thickness changes of $0.48{\pm}0.005$ to $67.7{\pm}0.02{\mu}m$ in 1.7 M sodium sulfate and those of $0.06{\pm}0.005$ to $17.7{\pm}0.05{\mu}m$ in sodium nitrate. Metal waste in modified electrolyte decontamination system showed the thickness change of $9.8{\pm}0.01{\mu}m$ while it reacted up to $3.7{\pm}0.03{\mu}m$ in conventional system with $0.3 A/cm^2$ of current density and 1.7 M sodium sulfate. Decontamination efficiencies of modified electrolytic process ate much hither than that of conventional electrolytic process when both are applied to metal waste.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.1
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• pp.138-144
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• 2016

Titanium is resistant to general corrosion and in sea water because of the passivity layer film on the surface of material, but may be attacked by environments that cause breakdown of the protective oxide layer including hydrochloric, sulfuric and phosphoric acids. In this study, the Ti alloys were solution heat treatment 5hours at $1066^{\circ}C$ and $966^{\circ}C$, and followed by aging heat treated, 1, 4, 8 and 16 hours in $500^{\circ}C$, $600^{\circ}C$ and $650^{\circ}C$ respectively. The heat treated specimens were measured micro Vicker's hardness, and then accomplished electrochemical polarization test for comparing corrosion in 1N sulfuric acid solution. Additionally, micro structures were taken for corrosion tested specimens. The results showed that corrosion resistance was higher in solution heat treated alloy than base and age heat treated metal. Measured corrosion resistants were increased as increasing aging heat treatment time and temperature.