| 摘要 |
#CMT# #/CMT# Two functionalities, oxidation protection and freedom from cracks, are united in the layer. Glass-like and glass ceramic compounds are employed as the matrix material. This reacts chemically with the surface of the substrate. The result of reaction is a reinforced gas barrier. Two properties are especially significant; the platelet-form active materials have sliding properties and the matrix has a degree of plasticity. These two effects confer to the coating, a high resistance to damaging effects of temperature reversal. Simultaneously the active materials act as oxidation inhibitors. #CMT# : #/CMT# Further active oxidation inhibitors can be added, for optimization in accordance with the conditions of use. The active materials are selected from MoS2, graphite, graphite fluoride, BN, CaF2, PbO and selenides, sulfides and telurides of: molybdenum, tungsten, niobium, tantalum, titanium and zirconium. They may include: titanium dioxide, tungsten dioxide and zirconium dioxide, carbon and silicates, e.g. talc and mica. Materials selected for a specific application may also be included. At least one active material has a definite application. In addition, metallic reactive compounds are used, e.g. Cr, Al, Zn or Ni. These improve oxidation protection and simultaneously consolidate the matrix. Additional inorganic fillers are incorporated into the matrix. These react with oxidizing gases to form less damaging salts, hence contributing to reduction of ceramic substrate oxidation. The coating solution is applied to ceramic or metallic substrates by spraying, rolling, immersion or flooding. It is applied to new plant parts or those already in operation. The applied layer is thermally hardened (from 200[deg]C) #CMT#USE : #/CMT# To form a coated layer resisting high temperatures and protecting against oxidation of ceramic and metallic components. Examples cited include: furnaces, combustion units, chemical plants and catalyst structures. #CMT#ADVANTAGE : #/CMT# The considerable problems of high temperature oxidation in e.g. furnaces or catalyst structures, are reduced or eliminated. No previous suitable solution has been devised, because micro-cracks always form in the coatings, allowing diffusion of corrosive gases. It is the combination of a gas barrier with temperature cycling resistance as described above, which is largely responsible for the improvement. The layered and platelet structure also lengthens the gas diffusion paths, hence inhibiting oxidation. Analogous systems are known in the food industry, where they are used in barrier films. |
