• Title/Summary/Keyword: Sol-gel coating

Search Result 620, Processing Time 0.028 seconds

Sol-gel Spin-coating of ZnO Co-doped with (F, Ga) as A Transparent Conducting Thin Film ((F, Ga) 코도핑된 ZnO 투명 전도 박막의 솔-젤 제조와 특성)

  • Nam, Gil Mo;Kwon, Myoung Seok
    • Journal of the Semiconductor & Display Technology
    • /
    • v.13 no.1
    • /
    • pp.91-95
    • /
    • 2014
  • (F,Ga) co-doped ZnO thin film on glass substrate was fabricated via a simple non-alkoxide sol-gel spin-coating. Contrary to the F single doped ZnO thin film, the (F,Ga) co-doped thin film showed a significant reduce in electrical resistivity after a second post-heat-treatment in reducing environment. The resulting decrease in electrical resistivity with Ga co-doping is considered to be resulted from the increases both carrier density and mobility. The optical transmittance of the (F,Ga) co-doped thin film in the visible range showed higher transmittance with Ga co-doping compared with F single doped ZnO thin film.

Continuous Nanocomposite Coatings on a Phosphor for the Enhancement of the Long-term Stability

  • Kim, Jong-Woung;Song, Jung-Oh;Kim, Chang-Keun
    • Proceedings of the Polymer Society of Korea Conference
    • /
    • 2006.10a
    • /
    • pp.233-233
    • /
    • 2006
  • [ $Y_{2}O_{2}S:Eu$ ], a red phosphor, coated with silica nanoparticles or nanocomposites composed of silica nanoparticles and polymeric materials such as PMMA and PVP was prepared via sol-gel process. Samples were prepared from four different methods coded P1, P2, P3, and P4. P1 includes a conventional sol-gel process and a dip-coating method while P2 has the same procedure with P1 except that nanocomposites containing both silica nanoparticles and polymer prepared by sol-gel process were used as coating materials. In P3 method, phosphors were dispersed in a solution containing silica precursor, i.e., TEOS and then polymerization was performed to coat onto the phosphors surface while P4 followed the same procedure with P3 except that a solution containing both TEOS and organic monomer were used in preparing coating materials. Among various coating methods examined in this study, uniform coating of phosphor could be achieved by using method P4, i.e., phosphor surface coating in a solution containing hydrophobic monomer and TEOS. Furthermore, $Y_{2}O_{2}S:Eu$ red phosphor coated with nanocomposite composed of PMMA matrix and silica nanoparticles exhibited enhanced PL intensity and long-term stability.

  • PDF

Thermally Curable Organic-inorganic Hybrid Coatings on Ophthalmic Lenses by the Sol-Gel Method (졸-겔법에 의한 안경렌즈의 열경화형 유-무기 하이브리드 코팅)

  • Yu Dong-Sik;Lee Ji-Ho;Ha Jin-Wook
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.7 no.3
    • /
    • pp.465-470
    • /
    • 2006
  • Coating are needed on ophthalmic lenses to enhance both the mechanical durability of the relatively soft plastic surface and the optical performance of lenses. Organic-inorganic hybrid materials as molar ratio of 3-glycidoxypropyltrimethoxysilane(GPTS), methyltrimethoxysilane(MTMS) and tetraethyl orthosilicate(TEOS) were used to improve the surface characteristics and the optical properties on allyl diglycol carbonate lenses. Coating for these plastics were at $140^{\circ}C$ for 4hrs, applied using the sol-grl process flow-coating technique. The coated lens properties of transmittance, adhesion, pencil hardness, abrasion resistance, hot water resistance and chemical resistance were investigated. The optimum properties was obtained when the ratio of GPTS : MTMS : TEOS was 1:1:2, respectively.

  • PDF

Fabrication of Single Layer Anti-reflection Thin Film by Sol-gel Method (Sol-gel법에 의한 단층 반사 방지막 제조)

  • Park, Jong-Guk;Jeon, Dae-Woo;Lee, Mi-Jai;Lim, Tea-Young;Hwang, Jonghee;Bae, Dong-Sik;Kim, Jin-Ho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.28 no.12
    • /
    • pp.821-825
    • /
    • 2015
  • Anti-reflective (AR) thin film was fabricated on a glass substrate by sol-gel method. The coating solution was synthesized with TEOS (tetraethlyorthosilicate) and poly ethylene glycol (PEG, 4.0 wt%). As the withdrawal speed of coating was changed from 0.1 mm/sec to 0.3 mm/sec, the thickness and refractive index of prepared thin films were changed. The reflectance and transmittance of coating glass fabricated by the withdrawal speed of 0.1 mm/sec were 0.62% and 95.0% in visible light range. The refractive index and thickness of single layer thin film were n= 1.29 and ca. 99.0 nm.

Preparation of Hard Coating Solutions with High Refractive Index for Polycarbonate Sheet by the Sol-Gel Method (Sol-Gel 법에 의한 Polycarbonate 시트에 적용 가능한 고굴절률을 보이는 하드코팅 용액의 제조)

  • Cheong, Il Yeop;Cho, Kyung In;Cheong, Sang Hyuk;Park, Hyo Nam;Song, Ki Chang
    • Korean Chemical Engineering Research
    • /
    • v.45 no.4
    • /
    • pp.335-339
    • /
    • 2007
  • In order to overcome the problem of poor hardness of transparent polycarbonate (PC) sheets, organic-inorganic hybrid hard coating solutions, which show a high refractive index above 1.58, were made by the sol-gel method. These hybrid coating solutions were obtained from mixture of titanium tetraisopropoxide (TTIP), and (3-glycidoxypropyl)trimethoxysilane (GPTMS). The PC sheets were spin-coated, and cured at $120^{\circ}C$ for 2 hr. Change of refractive index in the range of 1.53-1.61 was obtained by varying the GPTMS content. The refractive index of the coated film decreased with increasing the GPTMS content, while the pencil hardness of the coated film was found to increase with increasing the GPTMS content.

The Effects of SiO2 Addition and Cooling Rate Change by Sol-gel Processing in Semiconducting BaTiO3 Ceramics (반도성 $BaTiO_3$ 세라믹스의 Sol-gel법에 의한 $SiO_2$ 첨가 및 냉각속도 효과)

  • 권오성;정용선;윤영호;이병하
    • Journal of the Korean Ceramic Society
    • /
    • v.33 no.12
    • /
    • pp.1301-1310
    • /
    • 1996
  • Generally it requires high sintering temperatures more than 135$0^{\circ}C$ to make semiconductive BaTiO3 ceramics. Also it is very difficult to achieve a homogeneous mixing in solid-state reaction method. Therefore the liquid phase distributed to non-uniform dilute the characteristics of PTCR. In order to improve the uniformity this study is used the sol-gel coating method. Using this method we studied the new manufacturing process that had a high reproducibility and mass production capability. Tetraethyl orthosilicate (TEOS) was used as a source of Si. The semiconductive BaTiO3 ceramics which was produced by sol-gel method for the SiO2 addition and sintered between 124$0^{\circ}C$ and 130$0^{\circ}C$ showed almost same resistivity at room temperature among 125$0^{\circ}C$ and 130$0^{\circ}C$. As the results We could be sintered the semiconducting BaTiO3 ceramics at lower temperature even at 125$0^{\circ}C$ maintaining the same specific resistivity ratio ($\rho$max/$\rho$min) at 130$0^{\circ}C$. The specific resistivity both below and above the Curie temperature were increased by slow cooling and the steepness of the plots in the reasion of transition from low to high resistance increased as the cooling rate decreased.

  • PDF

Effects of Catalyst Coating Methods on NO Removal Characteristics of Functional Fabric Filters (촉매 코팅방법에 따른 기능성여과포의 NO 제거 반응 특성)

  • Kang, Min Pil;Song, Yun-Seob;Lee, Hyo Song;Kim, Sang Do;Park, Young Ok;Hwang, Taek-Sung;Rhee, Young-Woo
    • Korean Chemical Engineering Research
    • /
    • v.40 no.6
    • /
    • pp.725-728
    • /
    • 2002
  • A series of fabric filters including P-84, Nomex and PTFE were coated with a commercial $V_2O_5/TiO_2$ catalyst as an effort to develop a functional fabric filter of simultaneous removal of dust and NOx. The coating methods employed are sol-gel coating method, spray coating method and dip coating method, and the effects of coating method on NOx removal performance of functional fabric filter were investigated. Experimental conditions are as follows: the temperatures of $100-250^{\circ}C$ which are the normal operating temperature range of fabric filters, the space velocity of $5,000hr^{-1}$, the oxygen concentration of 6%, and the $NH_3/NO$ ratio of 1.0. Results showed that the sol-gel coating method gave the best NOx removal performance mainly due to its ability in controlling the amount of catalyst and uniform coating.

Hard Coatings on Polycarbonate Plate by Sol-Gel Reactions of Silicates and Melamine Derivative (폴리카보네이트 판 위에 Silicates와 Melamine 유도체의 졸-겔 반응을 이용한 하드 코팅)

  • Kim, Se-Ra;Kang, Min-Kyung;Shin, Young-Jae;Oh, Mee-Hye;Yoon, Yeo-Seong;Shin, Jae-Sup
    • Polymer(Korea)
    • /
    • v.31 no.6
    • /
    • pp.485-490
    • /
    • 2007
  • Hard coating was made on a polycarbonate plate using a sol-gel process with a melamine derivative and silicates, and examined as potential substitutes for automobile glass. Methylated poly(melamine-co-formaldehyde), tetraethoxysilane, and phenyltriethoxysilane were used to form a coating solution. The coatings on the polycarbonate plate were deposited using a sol-gel process. Poly(methyl methacrylate) was coated on the surface of polycarbonate in order to improve adhesion property. The optimum conditions and formulation to obtain excellent physical properties of the coating were determined. Adding the melamine derivative to the coating solution, the pencil hardness of the coating was improved. The hardness of a 3H class pencil, excellent abrasion resistance, and surface uniformity were found in the coated polycarbonate surface.

STUDY ON THE ENHANCING MICRO-ROUGHNESS OF POROUS SURFACED DENIAL IMPLANT THROUGH ANODIZATION (양극산화처리를 통한 다공성 임플랜트 표면의 표면거칠기 증대에 대한 연구)

  • Yoon, Tae-Ho;Song, Kwang-Yeob
    • The Journal of Korean Academy of Prosthodontics
    • /
    • v.44 no.5
    • /
    • pp.617-627
    • /
    • 2006
  • Statement of problem: HA has been used as a coating material on Ti implants to improve osteoconductivity. However. it is difficult to form uniform HA coatings on implants with complex surface geometries using a plasma spraying technique. Purpose : To determine if Ti6Al4V sintered porous-surfaced implants coated with HA sol-gel coated and hydrothermal treated would accelerate osseointegration. Materials and Methods : Porous implants which were made by electric discharge were used in this study. Implants were anodized and hydrothermal treatment or HA sol-gel coating was performed. Hydrothermal treatment was conducted by high pressure steam at $300^{\circ}C$ for 2 hours using a autoclave. To make a HA sol, triethyl phosphite and calcium nitrate were diluted and dissolved in anhydrous ethanol and mixed. Then anodized implant were spin-coated with the prepared HA sols and heat treated. Samples were soaked in the Hanks solution with pH 7.4 at $37^{\circ}C$ for 6 weeks. The microstructure of the specimens was observed with a scanning electron microscope (SEM), and the composition of the surface layer was analyzed with an energy dispersive spectroscope (EDS). Results : The scanning electron micrographs of HA sol-gel coated and hydrothermal treated surface did not show any significant change in the size or shape of the pores. After immersion in Hanks' solution the precipitated HA crystals covered macro- and micro-pores The precipitated Ca and P increased in Hanks' solution that surface treatment caused increased activity. Conclusion : This study shows that sol-gel coated HA and hydrothermal treatment significantly enhance the rate of HA formation due to the altered surface chemistry.

Preparation of Glass Thin Film onto Plastic Surface by Sol-Gel Process (Sol-Gel 공정으로 Plastic표면에 Glass박막 제조에 관한 연구)

  • 양천회
    • Journal of the Korean Society of Safety
    • /
    • v.13 no.1
    • /
    • pp.85-91
    • /
    • 1998
  • Sol-gel derived silica films were prepared by dip-coating onto polymethylmethacylate with Tetraethoxysilane(TEOS) as starting materials. Film properties such as viscosity and thickness were investigated as a function of dip speed, waterprecursor ratio, sol aging time. IR spectra of the gel films prepared from TEOS at various R are given. At small values of R the absorption peaks assignable to C-H vibration in $-OC_2H_5$ groups are observed around 3000 and 1500-1300 $cm^{-1}$. These bands indicate that the -$-OC_2H_5$ groups are retained in the gel at small values of R because of incomplete hydrolysis of TEOS. Film behaviour was interpreted in terms of the dependence of hydrolysis and condensation rates on the interplay between sol pH and waterprecursor ratio. Film thickness was found to increase by approximately a factor of two as waterprecursor ratio increased from two to six. Film thickness also increased with sol prepolymerization time. Surface quality was correlated with processing conditions.

  • PDF