High temperature coatings

Lackey, W.J., Stinton, D.P. and Seasc, J.D., Improved gas distribution for coating high-temperature gas-ceioled reactor fuel particles. Nuclear Technology, 1977, 35, 227 237. 

G-VG G-VG Molded by all processes, fluidized bed coatings High-temperature valve seats, chemical resistant pipe, coated vessels, insulation... 

Nanoscale sihcon oxide is widely used in microelectronics, optoelectronics and electronics are parts of the means of fire protection, coatings, high temperature adhesives, paints, various mortars. Medical and biotechnology applications comprising silica nanoparticles and sorbent molecular sieves of DNA delivery vehicles, proteins, anticancer agents [17]. 

Table 5.2. Coated high-temperature alloys or monolithic alloys potentially suited for AHTR needs... 

Vapor phase Thermal spray technologies EVD Columnar 100-500 pm h- 3-50 pm h Expensive High deposition rates, various compositions, possible thick and porous coatings, high temperatures necessary High reaction temperatures necessary, corrosive gases... 

Coated High-Temperature Alloys or Monolithic Alloys Will Likely Meet AHTR Needs... 

Polyaromatic hydrocarbons, PCBs, waxes, triglycerides Minimum temperature -10 °C Maximum temperature 480 °C (highest operating temperature of all stationary phases, aluminium coated, 370°C polyimide coated), high temperature phase... 

Mouldings, film, coatings high temperature resistance, chemically inert, excellent electrical insulator, very low coefficient of friction expensive, e.g. Teflon , Fluon . 

BN RS, ARE, CVD, Plama CVD Implantation mask. X-ray lithography mask Corrosion resistant 2q>pl >cations, wear resistant coating, high temperature applications... 

Formed commercially by the polymerization of S, NajCOj and PhX in a sealed container at 275--370 C, substituted derivatives are known but not fully evaluated. Used as high-temperature adhesives, for laminates and in coatings. 

Uses. 3-Pentenenitrile, 3PN, is used entirely by the manufacturers to make adiponitrile. i7j -2-Pentenenitrile, 2PN, can be cycli2ed catalyticaHy at high temperature to produce pyndine, a solvent and agncultural chemical intermediate. 2PN is also chlorinated to manufacture pentachloropyndine, an intermediate in the insecticide Dursban produced by Dow. Addition of ammonia to 2PN foUowed by reduction leads to 1,3-pentadiamine (Dytek ep), which is used as a curing agent for epoxy coatings and as a chain modifier in polyurethanes. 

Polyimide. Polyimide is a biaxiaHy oriented high performance film that is tough, flexible, and temperature- and combustion-resistant. Its room temperature properties compare to poly(ethylene terephthalate), but it retains these good characteristics at temperatures above 400°C. Its electrical resistance is good and it is dimensionally stable. The principal detriment is fairly high moisture absorbance. The main uses are for electrical insulation, particularly where high temperatures are prevalent or ionizing radiation is a problem. The films may be coated to reduce water absorption and enhance... 

A varnish is often appHed on top of the paint layers. A varnish serves two purposes as a protective coating and also for an optical effect that enriches the colors of the painting. A traditional varnish consists of a natural plant resin dissolved or fused in a Hquid for appHcation to the surface (see Resins, natural). There are two types of varnish resins hard ones, the most important of which is copal, and soft ones, notably dammar and mastic. The hard resins are fossil, and to convert these to a fluid state, they are fused in oil at high temperature. The soft resins dissolve in organic solvents, eg, turpentine. The natural resin varnishes discolor over time and also become less soluble, making removal in case of failure more difficult (see Paint and FINNISH removers). Thus the use of more stable synthetic resins, such as certain methacrylates and cycHc ketone resins, has become quite common, especially in conservation practice. 

Fiber-reiaforced panels covered with PVF have been used for greenhouses. Transparent PVF film is used as the cover for flat-plate solar collectors (114) and photovoltaic cells (qv) (115). White PVF pigmented film is used as the bottom surface of photovoltaic cells. Nonadhering film is used as a release sheet ia plastics processiag, particularly ia high temperature pressing of epoxy resias for circuit boards (116—118) and aerospace parts. Dispersions of PVF are coated on the exterior of steel hydrauHc brake tubes and fuel lines for corrosion protection. 

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