Thermal repair

Another viable application is the use of EB curing in the repair of aircraft composite parts. It was determined that most of the repairs are completed in 50-70% of the time required for a normal thermal repair. ... 

Ziac foil coated with a conductive, pressure-sensitive adhesive is used for repair of other ziac coatings or for imparting corrosion resistance at field sites. The 0.08-mm ziac tape or sheet has a 0.025-mm coaductive adhesive. The laminate is cut to size and pressed tightly to activate the adhesive. Conductive tape can be wrapped around pipe, especially around welds or connections. The corrosion resistance of this material is iatermediate between galvanized or thermally sprayed coatings and zinc-filled paints (21,50). 

Aluminide and sUicide cementation coatings such as TaAl on tantalum and MoSi2 on molybdenum oxidize at slow rates and possess some inherent self-repair characteristics. Fine cracks that appear and are common to these coatings can be tolerated because stable, protective oxides form within the cracks and seal them. Thermal cycling, however, accelerates faUure because of thermal expansion mismatch that ultimately dismpts the protective oxide coating. 

The thermal conductivity of an average boiler scale is 2.2 (W/m K) and that of complex silicate scales is 0.2-0.23 (W/m K). Since the furnace peak wall flux can be over 300,000 (W/m ) it may readily be seen that a small thickness of scale can raise the metal temperature into the creep region, resulting in very expensive repairs. 

Siloxane containing polyester, poly(alkylene oxide) and polystyrene type copolymers have been used to improve the heat resistance, lubricity and flow properties of epoxy resin powder coatings 43). Thermally stable polyester-polysiloxane segmented copolymers have been shown to improve the flow, antifriction properties and scratch resistance of acrylic based auto repair lacquers 408). Organohydroxy-terminated siloxanes are also effective internal mold release agents in polyurethane reaction injection molding processes 409). 

Karlsson D, Spanne M, Dalenea M, Skarping G (2000) Airborne thermal degradation products of polyurethane coatings in car repair shops. J Environ Monit 2 462 169... 

Early research on high temperature polymers concentrated primarily on thermal stability and paid little attention to their processability and cost. However, for a polymer to be successful as a c< miercially viable structural matrix, it must exhibit a favorable combination of processability, performance characteristics, and price. In particular, a desirable high temperature polymeric system for coatings, composites, and adhesives applications must exhibit adaptability to conventional processing techniques at low temperature and pressure, should exhibit good mechanical properties, acceptable repairability, weatherability, and cost effectiveness. 

Liu Y-L, Chen Y-W. Thermally reversible cross-linked polyamides with high toughness and self-repairing ability from maleimide- and furan-functionalized aromatic polyamides. Macromol Chem Phys 2007 208 224-232. 

For ex situ thermal desorption in general, 15 to 30 per ton ( 20 to 35 per metric ton) is required for direct operating costs including utilities and repairs. Unit transportation and setup costs typically range from 3 to 5 per ton ( 3.30 to 5.50 per metric ton). Excavation of contaminated soils and replacement of treated soils costs about 5 to 10 per ton ( 6 to 11 per metric ton) (D18527, p. 4)... 

As with other thermal treatment technologies, volatile metals will vaporize and be carried out of the unit with the airstream. The components of the reaction vessel often require frequent repair or replacement. 

Polymer resins were first introduced in the early 1940s as an aesthetic alternative to repair defects in anterior teeth. Some of the first resins were unfilled polymers of methyl methacrylate. Presently, these unfilled resins have been replaced by filled composite materials that limit the problems associated with polymerization volume shrinkage, abrasion or wear resistance, mechanical properties, water sorption, solubility, and thermal expansion. Polymeric composite materials generally consist of a monomer resin, a ceramic filler, a polymerization initiator or initiating system, and a coupling agent which binds the polymer... 

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