Study On High-temperature Chlorine Corrosion Resistance Of Ceramic Coatings Prepared By Slurry Method

The high temperature chlorine corrosion on the heat transfer surface of biomass boiler is a serious problem.Based on such problem,Industrial analysis,element analysis,ash composition analysis and TG-FTIR analysis were carried out for three kinds of biomass fuel in a power plant:solid wood particle plate,plywood and mixed sample.Innovative slurry spraying technology was used to prepare chlorine corrosion resistant coatings on two substrates of 15CrMoG and TP347 respectively.Gas phase and solid phase chlorine corrosion tests were carried out on coated samples and steel samples.The chloride corrosion resistance of the coating was studied by thermal analysis,SEM and EDS.Combined with the calculation of coal alkali metal grading and slagging characteristic index,it is showed that solid wood granular plate sample and plywood sample are high alkali coal and medium alkali coal,which have serious slagging tendency.Through the analysis of TG and DTG curves,the three biomass samples are all burned at about 600°C and both showed double loss peak characteristics.Combined with the analysis of combustion characteristics it is found that the plywood-like combustion characteristics are the best.By infrared spectroscopy it is found that the gas product components of solid wood granular plate sample and plywood sample pyrolysis combustion are similar and HCl gas was detected.The result of gaseous chlorine corrosion test suggests that 15CrMoG based coated samples have better corrosion resistance property than uncoated samples.The corrosion resistance property of coated samples improves 10.5times,13.4times and2.7times under 370?,395?and 420?respectively.Then the coating morphology indicates that coating and substrate exhibit a preferable bond state.The result of solid-state chlorine corrosion test suggests that ceramic coatings have better corrosion resistance property than 15CrMoG and TP347 based steel.The corrosion resistance property of coated 15CrMoG based samples improves 9.2times,5.2times and 12.5times under 370?,395?and 420?respectively.The results of15CrMoG based samples are analyzed with the thermal analysis kinetics.The thermal kinetics shows that the solid-state chloride corrosion mode function of both coated and uncoated samples are D2.And,the activation energy of the uncoated and coated samples is 10923.63J·mol^-1 and 2 200.217J·mol^-1.The activation energy of the coated steel in the reaction is lower than the uncoated one.The coating possesses preferable chlorine corrosion resistance.Then the coating morphology indicates that coating and substrate exhibit a preferable bond state.