• Journal of Welding and Joining
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• 제24권5호
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• pp.57-61
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• 2006

For the production of functional $TiO_2$-biodegradable plastic (polybutylene succinate:PBS) composite material with photocayalytic activity, we attempted to prepare $TiO_2$ coatings on PBS substrate by HVOF and plasma spraying techniques under various conditions. The microstructures of coatings were characterized with SEM and XRD analysis, and the photocatalytic efficiency of coatings was evaluated by the photo degradation of gaseous acetaldehyde. The effects of primary particle size and spraying parameters on the formation behavior, photocatalytic performance of the coatings have been investigated. The results indicated that for both the HVOF sprayed $P_{200}$ and $P_{30}$ coatings, the high anatase ratio of 100% can be achieved regardless of fuel gas pressure. On the other hand, the HVOF sprayed $P_7$ coating exhibited a largely decreased anatase ratio (from 100% to 49.1%) with increasing the fuel gas pressure, which may be attributed to much higher susceptibility of heat for 7 nm agglomerated powder. HVOF sprayed $P_{200}$ and $P_{30}$ coatings show better performance as compared to that of plasma sprayed $P_{200}$ coatings owing to the higher anatase ratio. However, the HVOF sprayed $P_7$ coatings did not show the photocatalytic activity, which may result from the extremely small reaction surface area to the photocatalytic activity and low anatase ratio.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2005년도 추계학술발표회 및 workshop
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• pp.183-184
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• 2005

Four different coatings deposited using cold spray process were studied with two different powder agglomerating techniques (spray d교 and evaporated powder) and using $TiO_2$ nano-sized powders with and without a 10wt% addition of ZnO. Characterization was performed by SEM, XRD and roughness test. Also the photocatalytic effect of the coatings was evaluated. Although the change of powder preparation techniques and the addition of ZnO into $TiO_2$ did not show appreciable variations in the surface morphology and Anatase phase transformation, it did show influence on the surface roughness of the coating, the highest roughness being found in the coatings made by spray powder prepared method. Regarding the photocatalytic effect it was observed that the using the spray dry coating and the addition of ZnO are promoter of purification at higher rates.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2005년도 춘계학술발표대회 개요집
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• pp.387-392
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• 2005

For the production of further functional bio-degradable plastic(polybutylene succinate:PBS) with $TiO_{2}$ as photocatalyst, which shows the decomposition of detrimental organic compound and pollutant under ultraviolet irradiation, we attempted to prepare $TiO_{2}$ coatings on PBS substrate by HVOF and plasma spraying techniques under various conditions. The microstructures of coatings were characterized with SEM and XRD analysis, and the photocatalytic efficiency of coatings was evaluated through the photo degradation of gaseous acetaldehyde. The effects of primary particle size and spraying parameters on the formation behavior, photo catalytic performance and mechanical characteristics of the coatings have been investigated. The results indicated that with respect to both the HVOF sprayed $P_{200}$ and $P_{30}$ coatings, the high anatase ratio off 100% can be achieved regardless of fuel gas pressure. On the other hand, the HVOF sprayed $P_{7}$ coating exhibited largely decreased anatase ratio (from 100% to 49.1%) with increasing the fuel gas pressure, which may be attributed to the much higher susceptibility to heat of 7nm agglomerated powder. In terms of photocatalytic efficiency, HVOF sprayed $P_{200}$ and $P_{30}$ coatings seem to predominate as compared to that of plasma sprayed $P_{200}$ coatings owing to the higher anatase ratio. However, the HVOF sprayed $P_{7}$ coatings didn't show the photo catalytic activity, which may result from the extremely small reaction surface area to the photo-catalytic activity and low anatase ratio. Such functional PBS with new roles is expected to cosiderably contribute to the reduction of aggravated environmel problem.

• Journal of Welding and Joining
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• 제21권4호
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• pp.39-45
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• 2003

Nano-TiO$_2$ photocatalytic coatings were deposited on the stainless steel 304(50$\times$70$\times$3mm) by the APS(Atmospheric Plasma Spraying). Photocatlytic reaction was tested in MB(methylene blue) aqueous solution. For applying nano-TiO$_2$ powders by thermal spray, the starting nano-TiO$_2$ powder with 100% anatase crystalline was agglomerated by spray drying. Plasma second gas(H$_2$) flow rate and spraying distance were used as principal process parameters which are known to control heat enthalpy(heat input). The relationship between process parameters and the characteristics of microstructure such as the anatase phase fraction and grain size of the TiO$_2$ coatings were investigated. The photo-decomposition efficiency of TiO$_2$ coatings was evaluated by the kinetics of MB aqueous solution decomposition. It was found that the TiO$_2$ coating with a lower heat input condition had a higher anatase fraction, smaller anatase grain size and a better photo-decomposition efficiency.

• Journal of Welding and Joining
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• 제21권4호
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• pp.46-55
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• 2003

TiO$_2$-WO$_3$(8.2wt%) coatings were prepared by the APS (Atmospheric Plasma Spraying) process to clarify the relationship between the process parameters(H$_2$ gas flow rate of plasma 2nd gas and spraying distance) of the APS coating and photo-decomposition efficiency kinetics of the MB(methylene blue) aqueous solution decomposition and to understand the effect of addition of WO$_3$ on photocatalytic properties of TiO$_2$ sprayed coating. Further, the temperature and velocity of flying particles were measured by DPV-2000 to investigate the relationship between microstructure of coatings and process parameters. Properties of coatins were investigated by XRD, SEM, XPS, RAMAN, UV/VIS spectrometer. In case of the TiO$_2$-WO$_3$(8.2wt%) coating, it had a lower anatase fraction than that of pure-TiO$_2$ coatings because of flying in the higher temperature plasma plume by the heavy weight of TiO$_2$, WO$_3$. And, when WO$_3$ added powders were spayed, the doping effects of W ions substituted into the Ti ion sites was not occured during melting and solidification cycles of spraying. It was found that the addition of WO$_3$ was ineffective effective on increasing photo-decomposition efficiency of TiO$_2$ sprayed coating.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2004년도 춘계 학술발표대회 개요집
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• pp.316-318
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• 2004

In recent years, plastic waste has been recognized as a worldwide environmental issue. To solve the disposal problem of the plastic waste, alternative treatment such as the use of biodegradable plastic(polybutylene succinate: PBS) is indeed highly in demand due to its merit of PBS buried in soil decomposed into carbon dioxide and water. In the present study, for the production of further functional PBS with TiO$_2$ as photocatalyst, which shows the decomposition of detrimental organic compound and pollutant under ultraviolet irradiation, we attempted to prepare photocatalytic TiO$_2$ coatings on PBS substrate by HVOF and plasma spraying techniques under various conditions using three kinds of agglomerated powders (P200: 200nm, P30: 30nm, P7: 7nm). The microstructures of coatings were characterized with SEM and XRD analysis, and the photocatalytic efficiency of coatings was evaluated through the photo degradation of gaseous acetaldehyde. Therefore, such functional TiO$_2$-Plastic composite material is expected to considerably contribute to the reduction of aggravated environmental problem.

• 한국전기화학회:학술대회논문집
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• 한국전기화학회 1999년도 제3회 총회 및 추계학술발표회
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• pp.3-4
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• 1999

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.90-90
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• 2010

We investigated the modification of optical response properties of titanium dioxide (TiO2) coatings on the ceramic water-purification filters by using ultraviolet-visible absorption spectroscopy and X-ray diffraction. The TiO2 coatings were prepared on ceramic substrate by e-beam evaporation method. These amorphous TiO2 were turned into anatase phase by heat treatment at $700^{\circ}C$ for 2 hours. The doping of N atoms into the TiO2 coatings was done by using 70KeV of N＋ ion implantation with the dose of $1.0{\times}1017$ ions/cm2, followed by post-irradiation heat treatment at $550^{\circ}C$ for 2 hours. Methylene blue test of TiO2 coatings to solar irradiation showed that the post-evaporation heated TiO2 was photocatalytic and N-doped TiO2 reacted to the visible part of solar irradiation.

• 한국건설순환자원학회논문집
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• 제10권1호
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• pp.56-65
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• 2022

본 연구에서는 시설물의 자기정화성능을 확보하기 위하여 이산화티탄 광촉매 용액을 코팅한 모르타르의 자기정화성능을 분석하였다. 광촉매 코팅 용액의 농도(1.5 %와 3.0 %), 초친수강화 용액 적용 유무 및 프라이머 용액의 사용 유무를 실험변수로 고려하였다. 광촉매 농도가 증가할수록 메틸렌블루 수용액의 색상 변화율이 증가하였으며, 이는 광촉매 농도가 증가할수록 자기정화성능이 증가하는 것을 나타낸다. 초친수성 광촉매 용액의 적용은 일반 광촉매 용액에 비해 자기정화성능을 다소 감소시킬 가능성이 있음을 나타낸다. 또한, 프라이머를 사용한 모르타르의 자기정화성능은 프라이머를 사용하지 않은 모르타르의 자기정화성능과 뚜렷한 차이를 나타내지 않는다. 한편, 낮은 농도(1.5 %)로 코팅된 모르타르에 비해 높은 농도(3.0 %)로 코팅된 모르타르 시편 표면의 코팅 균열이 미세하여 상대적으로 큰 광촉매 반응면적을 확보하고 자기정화성능 증가에 유리한 영향을 미친 것으로 판단된다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2004년도 춘계 학술발표대회 개요집
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• pp.314-315
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• 2004

As environmental issue threatens to be aggravated, applications of bio-degradable plastic (Polybutylene Succinate:PBS) tend to be increased. However, improvement of mechanical characteristics of PBS is indispensable for further widespread actual applications. Therefore, in order to produce further functional P8S with improved mechanical characteristics, TiO$_2$ coatings on PBS substrate were prepared under various spraying conditions using plasma and HVOF spraying techniques. The effects of thermal spraying methods and spraying parameters on coating properties could be confirmed. Moreover, wear behavior for TiO$_2$ coatings on PBS substrate has been also reviewed and characterized.