High Temperature Corrosion Resistant Coatings

In this paper , the development of heat resistant and anticorrosive coating was briefly reviewed .Tetraethylorthesilicate(TEOS) oligomers were prepared through the hydrolysis and condensation of TEOS with water, the author aslo explained how siloxane and inorganic pigments had effects on th properties of coating.Served as bond in base coating, hydrolysism, condensation and kinetic behavior of TEOS were studied. The mixture of TEOS oligomers was characterized by FTIR DTA and XRD.The data showed that ceramic coating properties were affected by temperature TEOS and analyst concentration. The best way to hydrolyze TEOS was decided that under the condition of 70 and pH=l-2, dripping TEOS into the mixture of n-butyl alcohol n-butyle acetate and ethylene glycol monobutyl ether, the production could be preserved more than four months ,and the solution is lucid.Analysis of these results obtained by the process of coating reveals that interesting correlation is found in conjuction with the coupling agent, the thickness of coating, pigments and the properties of coating: (i) it concluded that the coating consisted of base coat intermediated coat and top coat, especially when the total thickness is 105-110 u m, it provided the coating with the best properties to resist heat and corrosion.(ii) because of its scalelike structure MIO which was worked as the pigments in the intermediate coat could increase the properties of heat-resistance and protect metal from corrosive media effectively.(iii)Before varnishing, substrate had to be treated with coupling agent 602 which was diluted to 2% in ethanol solution .It was found that the metal treated in this way could promoted ashesion of coating. In addition, (iiii) studies of the anti-corrosion mechanism companing the molecular structure of silicone resins and natural guartz, the resin can be considered as organically modified quartz. Unlike quartz, however , every fourth oxygen group of a silicone resin is replaced by an organic group R, such as R-Si -O-Si-R.Chemically, silicone resins lie between purely inorganic and purely organic componds. When temperature rised, two silane molecular incorporate added water (H2O) and release two molecular of alcohol, as a result, coating was cured entiredly. The cured coating has high ability to resist heat and corrosion.