Study On Ceramic Heat Insulation Coating For Metal Surface

Ceramic heat insulation paint of organic-inorganic composite and inorganic ceramic heat insulation paint were prepared with inorganic aggregates and fillers as main components and with appropriate adhesion and fibers as additives, the paints are mainly used for the heat insulation of the equipment with high temperature and pipe transmission in oil, chemical and metallurgical industries. Taking organic epoxy resin as basic material, the effect of the main compound of paint on heat insulating performance was studied and the optimal ratio was determined. Taking inorganic high temperature resistant adhesive as basic material, the heat treatment mechanism of inorganic heat insulation paint was laid down on the basis of the thermostability of inorganic adhesion and paint. The surface morphology and internal structure of coating were analyzed with SEM, the heat insulating performance and physicochemical property of coating were tested. The results show that:Taking organic epoxy resin as basic material, when the ratio of epoxy resin and the toughening agent is 5 to 2, the heat insulating performance and toughness of coating were better. The heat insulation of paint was better taking ceramic fibers as the reinforcing fiber rather than carbon fibers and glass fibers. The excellent insulating performance of paint was got when the amount of zirconia was 10%, titanium was 12% and inorganic mineral was 36%. So the optimal formula of organic-inorganic composite ceramic heat insulation paint was: organic adhesion, 30%, ceramic fibers, 10%, the aggregates and fillers, 54%, agent, 6%.Taking inorganic high temperature resistant adhesive as basic material, the coating must be pretreated because chemical changes may take place when heating. The insulating performance of coating was excellent when the amount of expanded perlite was 3%. So the optimal ratio of inorganic ceramic heat insulation coating is: inorganic adhesion, 40%, ceramic fibers, 10%, the aggregates and fillers, 44%, agent, 6%.The SEM analysis results show that, the surface of coating was compact, the internal structure was porous, layered and reticulated. Some physical and chemical changes took place in the paints internal over 300℃and some micro-honeycomb structure was formed. So the ideal thermal barrier was formed because the fluxion of thermo-molecular was prevented by the micro-honeycomb in vacuum and semi-vacuum.The properties of heat insulating and physicochemical test results of paint show that: the adhesion level of paints was 1～2, the acidstability, alkalistability and salt resistant of paints were better, the micro-hardness approximates 150 HV. The thermal conductivities of paints were in the range of 0.058 to 0.072 W/(m·℃). The heat insulating performance was proportional to the thickness of paints.