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Coating Properties (coating + property)

Distribution by Scientific Domains
Polymers and Materials Science80%

Selected Abstracts

Conformal Nano-Sized Inorganic Coatings on Mesoporous TiO2 Films for Low-Temperature Dye-Sensitized Solar Cell Fabrication

ADVANCED FUNCTIONAL MATERIALS, Issue 2 2010
Larissa Grinis
Abstract Here, a new method based on sol,gel electrophoretic deposition to produce uniform high-quality inorganic conformal coatings on mesoporous nano-particulate films is presented. This novel sol preparation method allows for very fine control of the coating properties, thus inducing new adjustable functionalities to these electrodes. It is shown that the deposition of an amorphous TiO2 and/or MgO shell onto photoanodes used in dye-sensitized solar cells (DSSCs) improves their light-to-electric-power conversion efficiency without the need for sintering. It is proposed that the amorphous TiO2 coating improves the electronic inter-particle connection and passivates the surface states. The insulating MgO coating further reduces the electron transfer from the conduction band into the electrolyte while the electron injection from the excited dye state remains unperturbed for thin coatings. Using a low-temperature method for DSSC production on plastic substrates, a maximum efficiency of 6.2% applying pressure together with an optimized TiO2 coating is achieved. For systems that cannot be pressed a conversion efficiency of 5.1% is achieved using a double shell TiO2/MgO coating. [source]

Effects of Rice Batter on Oil Uptake and Sensory Quality of Coated Fried Okra

JOURNAL OF FOOD SCIENCE, Issue 1 2005
Fred F. Shih
ABSTRACT: Okra was coated and deep-fat fried with batters of flour sources including rice flour, a mixture of rice flour and small amounts of pregelatinized rice flour (PGRF), and, as a control, traditional wheat flour. The addition of PGRF, up to 8%, enhanced batter viscosity and the coating properties of the rice batter. Oil uptake of the fried batter decreased with the addition of up to 5% PGRF. Rice flour fried batters, with and without PGRF, were found to absorb substantially lower oil, by as much as 51 %, compared with the wheat batter. The fried okra coated with the rice batter containing 5% PGRF, when evaluated for sensory properties on appearance and surface attributes, was found to be superior or equal to those with the wheat batter and rice batter without PGRF. Particularly, its golden brown color is considered more desirable than the lighter yellow color of the other 2 entities. Similarly, most of its 1st-bite and after-chew properties were slightly better and were in the normal range of commercially available products. Specifically, its distinctive crispiness is considered a positive attribute, whereas its slightly higher tooth packing properties, while remaining in the range of commercial products, may be noticeable to some consumers. [source]

Microstructure,Property Correlations in Industrial Thermal Barrier Coatings

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2004
Anand A. Kulkarni
This paper describes the results from multidisciplinary characterization/scattering techniques used for the quantitative characterization of industrial thermal barrier coating (TBC) systems used in advanced gas turbines. While past requirements for TBCs primarily addressed the function of insulation/life extension of the metallic components, new demands necessitate a requirement for spallation resistance/strain tolerance, i.e., prime reliance, on the part of the TBC. In an extensive effort to incorporate these TBCs, a design-of-experiment approach was undertaken to develop tailored coating properties by processing under varied conditions. Efforts focusing on achieving durable/high-performance coatings led to dense vertically cracked (DVC) TBCs, exhibiting quasi-columnar microstructures approximating electron-beam physical-vapor-deposited (EB-PVD) coatings. Quantitative representation of the microstructural features in these vastly different coatings is obtained, in terms of porosity, opening dimensions, orientation, morphologies, and pore size distribution, by means of small-angle neutron scattering (SANS) and ultra-small-angle X-ray scattering (USAXS) studies. Such comprehensive characterization, coupled with elastic modulus and thermal conductivity measurements of the coatings, help establish relationships between microstructure and properties in a systematic manner. [source]

Werkzeugbeschichtungen für die Trockenbearbeitung,

MATERIALWISSENSCHAFT UND WERKSTOFFTECHNIK, Issue 10 2006
E. Abele
PVD coating; tribology; dry machining; tool wear Abstract Bei der Trockenbearbeitung wirkt an der Werkzeugschneide ein Belastungskollektiv aus mechanischen, thermischen und chemischen Einflussgrößen. Im Vergleich zur konventionellen Bearbeitung unter Verwendung von Vollstrahl-Emulsionskühlung erhöht die Trockenbearbeitung die auf den Schneidkeil wirkenden Belastungen. Eine sehr gute Möglichkeit die Schneide vor thermischen, abrasiven und tribo-oxidativem Verschleißangriff zu schützen stellt die Verwendung von PVD Beschichtungen dar. Neu entwickelte PVD Beschichtungen aus CrxAlyYzN, CrxAlyBzN und CrxAlySizN- wurden sowohl im tribologischen Modelltest als auch im realen Zerspanungstest auf ihre Eignung zur Trockenbearbeitung untersucht. In diesem Paper wird neben der verwendeten Beschichtungstechnologie detailliert auf die Schichteigenschaften eingegangen. Im Zusammenhang mit dem im Zerspanungstest gemessenen Verschleißverhalten und der Prozesskräfte werden anschließend Rückschlüsse auf das weitere Optimierungspotential dieser Schichtsysteme gezogen. Tool coatings for dry machining During dry machining a strain collective consisting of mechanical, thermal, and chemical loads is imposed upon the cutting edge. Compared to conventional machining using cooling lubrication fluids, the loads are increased in dry cutting. A feasible solution to protect the cutting edge from thermal wear, abrasion, and tribo-oxidation is the application of hard coatings. Newly developed CrxAlyYzN, CrxAlyBzN and CrxAlySizN PVD coatings were both evaluated in tribological model tests and machining tests concerning their suitability for dry cutting applications. Herein, the used coating technology and the coating properties are described in detail. The measured tool wear and the process forces give further hints for the optimization of the coating system. [source]

Gas Phase Modification of Superhard Carbon Coatings Deposited by Pulsed DC-Arc-Process

PLASMA PROCESSES AND POLYMERS, Issue S1 2009
Werner Grimm
Abstract The pulsed vacuum arc discharge (pulsed arc) is the most efficient PVD technology for deposition of hard amorphous carbon coatings on tools and machinery parts. Due to the pulsed arc discharge a stable evaporation process and the efficient deposition of hydrogen-free a-C type coatings is possible. This paper shows that the pulsed arc enables the deposition of ta-C and modified a-C coatings with interesting coating properties in a wide pressure range of argon, acetylene and ammonia gas atmosphere. Coatings with different gas flow rates of these gases were deposited on steel substrates. The coating properties were characterized by using different analytical methods for determination of structure, hardness, friction and wear behaviour. The changes of film properties in dependence of the kind and the rate of gas flow are compared and discussed. [source]