Home About us Contact
|
Home About us Contact | ||
|
|
||
Dip Coating (dip + coating)
Selected AbstractsSolution-Deposited Zinc Oxide and Zinc Oxide/Pentacene Bilayer Transistors: High Mobility n-Channel, Ambipolar, and Nonvolatile Devices,ADVANCED FUNCTIONAL MATERIALS, Issue 12 2008Bhola Nath Pal Abstract A solution processed n-channel zinc oxide (ZnO) field effect transistor (FET) was fabricated by simple dip coating and subsequent heat treatment of a zinc acetate film. The field effect mobility of electrons depends on ZnO grain size, controlled by changing the number of coatings and zinc acetate solution concentration. The highest electron mobility achieved by this method is 7.2,cm2 V,1 s,1 with On/Off ratio of 70. This electron mobility is higher than for the most recently reported solution processed ZnO transistor. We also fabricated bilayer transistors where the first layer is ZnO, and the second layer is pentacene, a p-channel organic which is deposited by thermal evaporation. By changing the ZnO grain size (or thickness) this type of bilayer transistor shows p-channel, ambipolar and n-channel behavior. For the ambipolar transistor, well balanced electron and hole mobilities are 7.6,×,10,3 and 6.3,×,10,3,cm2 V,1 s,1 respectively. When the ZnO layer is very thin, the transistor shows p-channel behavior with very high reversible hysteresis. The nonvolatile tuning function of this transistor was investigated. [source] Spontaneous Vertical Ordering and Pyrolytic Formation of Nanoscopic Ceramic Patterns from Poly(styrene- b -ferrocenylsilane),ADVANCED MATERIALS, Issue 4 2003K. Temple The rapid generation of nanopatterned surfaces using thin films of the amorphous diblock copolymer poly(styrene- b -ferrocenylethylmethylsilane) (PS- b -PFS) is reported. Spontaneous self-assembly into vertically oriented cylinders of PFS in a PS matrix is observed on a variety of substrates by spin or dip coating, irrespective of the substrate surface polarity. Pyrolysis of the films affords arrays of 20 nm Fe-containing ceramic nanoparticles, (see Figure, AFM, 4 ,m2 scan area). [source] Laser monitoring of non-Newtonian liquids during dip coatingAICHE JOURNAL, Issue 12 2009Alexandre F. Michels Abstract Dip coated films, widely used in the coating industry, are usually measured by capacitive methods with micrometric precision. In this work, interferometric determination of thickness evolution in real time, for the first time to our best knowledge, is applied to volatile non-Newtonian liquids with several viscosities and distinct dip withdrawing speeds. Thickness evolution during the process depends on time as predicted by a power law model. Comparison with measured results (uncertainty of ± 0.007 ,m) showed very good agreement after initial steps of the process. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Fabrication and Characterization of Anode-Supported Tubular Solid-Oxide Fuel Cells by Slip Casting and Dip Coating TechniquesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 2 2009Lan Zhang High-performance anode-supported tubular solid-oxide fuel cells (SOFCs) have been successfully developed and fabricated using slip casting, dip coating, and impregnation techniques. The effect of a dispersant and solid loading on the viscosity of the NiO/Y2O3,ZrO2 (NiO/YSZ) slurry is investigated in detail. The viscosity of the slurry was found to be minimum when the dispersant content was 0.6 wt% of NiO/YSZ. The effect of sintering temperature on the shrinkage and porosity of the anode tubes, densification of the electrolyte, and performance of the cell at different solid loadings is also investigated. A Ni/YSZ anode-supported tubular cell fabricated from the NiO/YSZ slurry with 65 wt% solid loading and sintered at 1380°C produced a peak power output of ,491 and ,376 mW/cm2 at 800°C in wet H2 and CH4, respectively. With the impregnation of Ce0.8Gd0.2O2 (GDC) nanoparticles, the peak power density increased to ,1104 and ,770 mW/cm2 at 800°C in wet H2 and CH4, respectively. GDC impregnation considerably enhances the electrochemical performance of the cell and significantly reduces the ohmic and polarization resistances of thin solid electrolyte cells. [source] Preparation and Electrical Properties of an Anodized Al2O3,BaTiO3 Composite FilmJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2008Xianfeng Du A highly stable, water-based barium titanate BaTiO3, BT, sol was synthesized using a sol,gel route through a chelate lactate technique. Dried BT precursor powders were measured by thermal gravimetry,differential thermal analysis and X-ray diffraction. It was found that BT powders first converted into barium carbonate BaCO3, Ti complex, and intermediate phase Ba2Ti2O5CO3, and then transformed into perovskite phase BaTiO3. The crystallization temperature was about 550°C. The low-voltage etched aluminum foils were covered with BT sol by dip coating, and then annealed at 600°C for 30 min in air. After that, the samples were anodized in a 15 wt% aqueous solution of ammonium adipate. The voltage,time variations during anodizing were monitored, and the electrical properties of the anodic oxide film were examined. It was shown that the specific capacitance, the product of specific capacitance and withstanding voltage, and leakage current of samples with a BT coating were about 48.93%, 38.50%, and 167% larger than that without a BT coating, respectively. [source] Chromium-Free Corrosion Resistance of Metals by Ceramic CoatingJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2001Satomi Ono Metal surfaces can be improved in terms of thermal, mechanical, and chemical properties by a ceramic coating. The chromium-free corrosion resistance of stainless steel was achieved using a chemical solution method. Precursor solutions were prepared from metal alkoxides and were deposited on stainless-steel surfaces by dip coating and heat-treating at temperatures <500°C. The stainless steel was coated by silica, zirconia, and titania single-layer coating films, and/or coated by silica/zirconia and silica/titania double-layer coating films. The corrosion resistance was improved remarkably by a submicrometer silica-based coating on the stainless steel. [source] The effect of three different calcium phosphate implant coatings on bone deposition and coating resorption: a long-term histological study in sheepCLINICAL ORAL IMPLANTS RESEARCH, Issue 3 2005Christian Schopper Abstract: The present study investigated the hypothesis that hydroxyapatite (HA), tricalcium phosphate (TCP), and a HA-gel coated on endosseous titanium (Ti) implants by spark discharging (SD) and dip coating would achieve predictable osseointegration without evident bioresorption of the coatings on the long term. A costal sheep model was used for the implantation of the HA/SD, HA/TCP/SD, and HA-gel/SD specimens, which were retrieved 6 and 12 months following implantation. HA and Ti coatings on implants obtained by conventional plasma spraying (HA/PS, Ti/PS) were used as controls. Microscopy showed that osseointegration was achieved from all types of implants. No evidence for bioresorption of the HA/SD, HA/TCP/SD, and HA-gel/SD coatings was present but cohesive failure with disruption of the coating/implant interface was seen. A statistical analysis of the histomorphometrical data showed no time-dependent effect, however. HA/PS coatings achieved significantly higher bone,implant contact (BIC) percentages of the total implant surface (toBIC) than the other types of coatings (P=0.01). If the BIC percentages were traced separately for implant portions placed into cortical and cancellous bone (coBIC and caBIC, respectively), detailed analysis showed that the caBIC values of HA-gel/SD and HA/PS coatings were significantly higher than that of the other types of coatings (P=0.01). CaBIC values were highly correlated with toBIC values (P<0.001). The present study showed that the preparation techniques used produced thin, dense, and unresorbable coatings that achieved osseointegration. Compared with the control coatings, however, only HA-gel/SD coating can be recommended from the investigated preparation techniques for a future clinical use if a better coating cohesion is achieved. Résumé L'étude présente a étudié l'hypothèse que le recouvrement par de l'hydroxyapatite, du phosphate tricalcique et un gel d'hydroxyapatite sur les implants en titane par décharges spark et recouvrement par trempage pourrait apporter une ostéïntégration prévisible sans biorésorption importante des recouvrements à long terme. Un modèle de mouton a été utilisé pour l'implantation de spécimens HA/SD, HA/TCP/SD et gel-HA/SD qui ont été enlevés six et douze mois après leur insertion. Les implants recouverts d'hydroxyapatite et de titane obtenus par plasma-spray conventionnel (HA/PS et Ti/PS) ont été utilisés comme contrôles. La microscopie a montré que l'ostéoïntégration a été réalisée pour tous les types d'implants. Aucune évidence pour la biorésorption de HA/SD, HATCP/SD, et gel-HA/SD n'était présente mais un échec de cohésion avec destruction de l'interface implant/recouvrement a été mis en évidence. Une analyse statistique des données histomorphométriques ne montrait cependant aucun effet dépendant du temps. Les recouvrements HA/PS montraient des pourcentages de contact os/implant significativement plus importants de la surface implantaire totale (BIC) que les autres types de recouvrement (p=0,01). Lorsque les pourcentages de contact os-implant étaient lus séparément pour les portions implantaires placées dans l'os cortical ou l'os spongieux (respectivement coBIC et caBIC), l'analyse détaillée montrait que les valeurs caBIC du gel- HA/SD et des recouvrements HA/PS étaient significativement plus importants que dans les autres types de recouvrement (p<0,01). Les valeurs CaBIC étaient en relation étroite avec les valeurs toBIC (p<0,001). L'étude présente a montré que les techniques de préparation utilisées produisaient des recouvrements non-résorbables denses et fins qui permettaient l'ostéoïntégration. Cependant, comparé aux recouvrements contrôles, seul le recouvrement gel-HA/SD pouvait être recommandé avec les techniques de préparation étudiées pour une utilisation clinique future si une cohésion de recouvrement meilleure est assurée. Zusammenfassung Die vorliegende Studie untersuchte die Hypothese, dass Hydroxyapatit, Trikalziumphoshat und ein Hydroxyapatit-Gel als Beschichtung auf enossalen Ti-Implantaten zur voraussagbaren Osseointegration über einen langen Zeitraum ohne Bioresorption der Beschichtung führen. Die Beschichtungen wurden durch Funkenentladung und Tauchbeschichtung aufgetragen. Für die Implantation der HA/SD, HA/TCP/SD und HA-Gel/SD wurde ein Schafmodell verwendet. Die Proben wurden 6 und 12 Monate nach Implantation entnommen. Als Kontrolle dienten Hydroxyapatit- und Titanbeschichtungen (HA/PS und Ti/PS), welche mittels Plasmaspray aufgetragen worden waren. Die mikroskopische Untersuchung zeigte, das bei allen Implantattypen eine Osseointegration erreicht wurde. Bei den HA/SD, HA/TCP und HA-Gel/SD Beschichtungen waren keine Anzeichen von Bioresorption vorhanden, aber es konnten kohäsive Misserfolge mit Abrissen im Bereich der Implantat/Beschichtung-Berührungsfläche gesehen werden. Eine statistische Analyse der histomorphometrischen Daten zeigte jedoch keinen zeitabhängigen Effekt. Die HA/PS Beschichtungen erreichten signifikant höhere Knochen-Implantat-Kontakt Prozentwerte der gesamten Implantatoberfläche (toBIC) als die anderen Beschichtungen (P=0.01). Wenn die Knochen-Implantat-Kontakt Prozentwerte für Implantatbereiche, welche im kortikalen und spongiösen Knochen (coBIC und caBIC) lagen, separat ausgemessen wurden, so zeigte die detaillierte Analyse, dass die caBIC Werte von HA-Gel/SD und HA/PS Beschichtungen signifikant höher waren als bei allen anderen Typen von Beschichtungen (P=0.01). Die caBIC Werte zeigten eine starke Korrelation mit den toBIC Werten (P<0.001). Die Studie zeigte, dass das verwendete Herstellungsverfahren dünne, dichte und nicht resorbierbare Beschichtungen ergab, welche eine Osseointegration erreichten. Im Vergleich mit den Kontrollbeschichtungen können jedoch nur die HA-Gel/SD Beschichtungen der untersuchten Herstellungsverfahren für den weiteren klinischen Gebrauch empfohlen werden, falls eine bessere Kohäsion der Beschichtung erreicht werden kann. Resumen El presente estudio investigó la hipótesis de que la hidroxiapatita, el fosfato tricálcico y un gel de hidroxiapatita cubriendo implantes endoóseos de Ti por medio de chisporroteo e inmersión pueden lograr una osteointegración predecible sin una biorreabsorción evidente de las cubiertas a largo plazo. Se usó un modelo costal de oveja para la implantación de especímenes HA/SD, HA/TCP/SD, y gel-HA/SD que se retiraron a los 6 y a los 12 meses de la implantación. Como control se usaron cubiertas de hidroxiapatita y titanio en implantes obtenidos por medio de pulverización de plasma convencional (HA/SD, Ti/PS). La microscopía demostró que la osteointegración se logró en todos los tipos de implantes. No existió evidencia de biorreabsorción de las cubiertas HA/SD, HA/TCP/SD, y gel-HA/SD pero se observó fallos en la cohesión con disrupción de la interfase cubierta/implante. Un análisis estadístico de los datos histomorfométricos no mostró, sin embargo efectos dependientes del tiempo. Las cubiertas HA/PS lograron unos porcentajes de contacto hueso-implante significativamente mayores del total de la superficie del implante (toBIC) que los otros tipos de cubiertas (P=0.01). Si se ubicaran los porcentajes de contacto hueso-implante separadamente para porciones situadas dentro de hueso cortical o esponjoso (coBIC y caBIC respectivamente), un análisis detallado mostró que los valores caBIC de las cubiertas de HA-gel/SD y HA/PS fueron significativamente mayores que aquellos de los otros tipos de cubiertas (P<0.001). El presente estudio mostró que las técnicas de preparación usadas produjeron cubiertas finas, densas y no reabsorbibles que alcanzaron la osteointegración. De todos modos, comparadas con las cubiertas de control, solo la cubierta HA-gel/SD pude ser recomendada desde las técnicas de preparación investigadas para un futuro uso clínico si se lograse una mejor cohesión de cubierta. [source] | ||||||||||