Temperature coatings

Operation and Control. Control of a chromium phosphate conversion coating bath requires monitoring chromium and aluminum concentrations, active fluoride level, and temperature. Coating weight is very sensitive to active, ie, uncomplexed, fluoride. An innovative electrochemical method using a siHcon electrode (25) is employed for measuring active fluoride. A special precaution in chromium phosphate bath operation is the... 

Gold purple, often caHed Purple of Cassius, is a tin oxide gel colored by finely divided gold (7). It has good coverage and brilliance in low temperature coatings such as porcelain enamels. It is a very expensive pigment, because of its difficult preparation as well as the price of gold. 

Bernstein, H.L., High Temperature Coatings for Industrial Gas Turbine Users, Proceedings of the 28th Turbomachinery Symposium, Texas A M University p. 179 1999. 

Sudarshan, T. and Dahorte, N. 1999. High-Temperature Coatings. Dekker, New York. 

Once an appropriate laboratory-scale process has been established, many of the key elements of the process should have been determined. Some operating parameters (such as inlet-air temperature, coating formulation to be used, and solids content of the coating solution/suspension) can be directly translated to the larger-scale process. Others, however, will have to change, and these include ... 

Polymer Properties. The single most important feature of the parylenes, that feature which dominates the decision for their use in any specific situation, is the vapor deposition polymerization (VDP) process by which they are applied. VDP provides the room temperature coating process and produces the films of uniform thickness, having excellent thickness control, conformality, and purity. The engineering properties of commercial parylenes once they have been formed are given in Table 2. 

The pyrolysis products from 9.13 can give essentially pure silicon carbide in 89% yield. Intermediates that contain from 5 to 25% allyl functionalized units give ceramics with progressively larger amounts of carbon beyond the 1 1 Si C ratio. This process has been developed into a manufacturing sequence for the production of reinforced composites for aircraft brakes and high temperature coatings. 

T-type die with high viscosity melts does not produce a uniform distribution, however it is used with high temperature coating, low viscosity melts that result in an acceptable distribution, and... 

High Temperature Coatings HI, TMS Annual Meeting, San Diego, CA., 1999. 

J.H. Park, Intermetallic and Electrical Insulator Coatings on High-Temperature Alloys in Liquid-Lithium Environments, in Elevated Temperature Coatings Science and Technology I, eds. N.B. Dahotre. J.M. Hampikian, and J.J. Stiglich, The Minerals, Metals, and Materials. Section, 1995, pp.227-240. 

Use High-temperature coatings, laminates and composites for aerospace vehicles, ablative materials, oil sealants and retainers, adhesives, semiconductors, valve seats, bearings, insulation for cables, printed circuits, magnetic tapes (high- and low-tem-perature-resistant), flame-resistant fibers, binders in abrasive wheels. 

High humidity (85%) caused a drastic increase in tack-free time when the substrate was maintained at 35°C or less. When the substrate temperature was raised to 45°C, the effect of high humidity on tack-free time was overcome and rapid cure was observed. Under commercial UV curing conditions (i.e., multiple 200 watt per inch lamps and no control of substrate temperature), coatings would ordinarily reach or exceed 45°C on exposure to the mercury arcs and this would tend to obscure the effects of high humidity. 

Initially, the experiments apply a commercially available polyimide coating, which is well known from many microelectronic applications. The polyimide (PI 2545, HD Microsystems GmbH) is a high-temperature coating that can be patterned by a positive photoresist. It is dissolved in the same process step as the exposed resist using an alkaline photoresist developer [6], but by different etching rates. 

A brief summary of the silicones in high-temperature coating applications follows ... 

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