Home About us Contact
|
Home About us Contact | ||
|
|
||
Coating Qualities (coating + quality)
Selected AbstractsMicrostructure,property,quality-correlated paint design: An LMC-based approachAICHE JOURNAL, Issue 1 2009Jie Xiao Abstract Paint is designed to offer various chemical and physical properties for surface protection, styling, and appearance. Nevertheless, the anticipated quality of the surface coating is frequently unsatisfactory, which is often attributed to paint formulation. As new demands on coating performance continuously emerge, paint formulation design becomes much more challenging than ever. It is recognized that paint design can be significantly improved with the help of advanced computational methods, as they can provide great freedom and control over the investigation of paint formulation through any number of in silico experiments virtually under any application conditions. This article introduces a lattice Monte Carlo based computational methodology for paint formulation design. By this methodology and structural analysis techniques, a variety of correlations among paint material, curing condition, coating microstructure, and coating qualities can be generated, which are critical for the development of superior paint formulations. A comprehensive study on acrylic-melamine-based paint design and analysis demonstrates the methodological efficacy. © 2008 American Institute of Chemical Engineers AIChE J, 2009 [source] Field study on superheater tubes in the loop seal of a wood fired CFB plantMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 12 2004A. Nafari Abstract Two full scale superheaters were exposed in the loop seal of a 30 MW wood-fired CFB plant in Nässjö, Sweden, for one firing season each. Some austenitic steel tubes from the first tube bundle were reinstalled in the second superheater. The superheater tubes were made from one ferritic steel, X10 (Fe8.8Cr) and three austenitic steels; Esshete 1250 (Fe15Cr9Ni6Mn), 347H (Fe17Cr11Ni) and AC66 (Fe27Cr32Ni). Commercial coatings mainly on iron, nickel and carbide base were deposited on some of the X10 and 347H tubes. The material wastage kinetics was non-linear showing that pure corrosion and not erosion-corrosion is the major degradation mechanism in the loop seal. It is however clear that the environment is not very aggressive and the corrosion attack on the uncoated tubes is very small. The largest oxide thickness was only about 150 ,m recorded on the X10 alloy. The austenitic steels mainly suffered from internal corrosion and grain boundary corrosion, the extent and distribution of which strongly depended on the alloy composition. Generally, it was more pronounced in the regions with the thinnest deposit layers. Eight out of 17 coating qualities tested were unaffected by the exposure. Corrosion was only recorded on the lowest alloyed iron based coatings. The only coatings which could not resist the conditions in the loop seal were the carbide containing Metco 3006 and Metco 3007, where severe oxidation and delamination took place. Also the thermally sprayed Inconel 625 coating delaminated, but this was rather due to a mechanical failure resulting from thermal expansion. [source] Anelastic Behavior of Plasma-Sprayed Zirconia CoatingsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2008Yajie Liu Low-temperature thermal cycling of plasma-sprayed zirconia coatings reveals unique mechanical responses in their curvature measurements, namely nonlinear and cyclic hysteresis, collectively termed as anelastic. These features arise from the inherent layered, porous, and cracked morphology of thermal-sprayed ceramic materials. In this paper, the mechanisms of anelasticity are characterized by crack closure and frictional sliding models, and stress,strain relations of various thermal-sprayed zirconia coatings were determined via an inverse analysis procedure. These results demonstrate process conditions such as powder morphology and spray parameters significantly influence the mechanical behaviors of coatings. The unique anelastic responses can be used as valuable parameters in identifying coating quality as well as process reliability in manufacturing. [source] Analyses of Thick Lithium Coatings Deposited by Sputter-Evaporation and Exposed to AirPLASMA PROCESSES AND POLYMERS, Issue S1 2009C. Rigaux Abstract Lithium coatings on various substrates have numerous applications: Boron neutron capture therapy, neutron activation analysis, super-conducting tokamak etc. Traditionally these coatings are produced by well-known techniques such as electrochemistry and evaporation. In this work, we investigated a new method based on sputter-evaporation, which enables thick coatings (>10,µm) to be built on various substrates within a short timeframe. In order to minimize the process time, evaporation techniques can be used but the coating quality suffers. Moreover, it is well known that the use of DC magnetron sputtering results in the deposition of good quality coatings (smoothness, density, adhesion); however, the deposition rate is low. The rationale of this work is to combine these two techniques, yielding a sputter-evaporation process that possesses the advantages of each separate technique. Li is placed in a stainless steel crucible (cathode), and heated by the plasma generated by a magnetron discharge. The Li temperature is measured by a thermocouple welded onto the cathode and measured at different plasma power densities. The deposition rate of lithium is measured using a quartz balance and by profilometry, at several temperatures (from 0 to 580,°C). Li samples were depth-profiled with the resonant nuclear reaction 7Li(p,,)7. In addition to the concentration, certain characteristics like the density and the chemical reactivity of layers, are also important. Thus we have studied the evolution of the density with time, estimated by weight and profilometry measurements, and the change in morphology, by cross-sectional scanning electron microscopy (SEM), of samples exposed to air at room temperature. The evolution of the film compounds have also been determined by X-ray powder diffraction. These physical properties have been investigated for various bias substrates during deposition. [source] | ||||||||||