Research On The Ability Of Power Plant Boiler Coating To Resist High Temperature Sulfate Corrosion

High-temperature sulfur corrosion of Waterwall tubes is one of technical problems encountered in power plant boiler, the corrosion mechanism and coating technology for protecting is the current research focus in the material field. In this thesis, the corrosion mechanism of water wall of power plantboiler was studied, and the corrosion-resistant coatings sprayed by Tungsten inert gas(TIG) spray technology were made had metallurgy combinative property. Experimental investigation of high temperature sulfate corrosion of LQG1000 and CT45 coating which are made with TIG welding cladding technology at high temperature spreading salt experiment. The SEM,EDS and XRD are used to analysise the microstructure and the compositions of the corrosion products, using thermal analysis kinetic experimental are analysed,and obtained the temperature of heat corrosion kinetic curve.As a comparative analysis substrate material 20g specimens and coating material together for the test.The results show that the high temperature sulfate corrosion and temperature are directly related,when temperature rise the corrosion rate has been obviously paced up.In 650℃temperature environment corrosion rate almost for 550℃temperature environment of 3 times.At the start of the experiment, the corrosion rate of the two kinds of coating almost a straight-line growth, after a short time gradually incline to gently.It shows that the surface of coating formed hinder corrosion protective layer.Relative 20g speaking CT45coating and LQG1000 coating of corrosion rate respectively nearly 10 times and 5 times,this means that the two coating are good corrosion resistance. Resistance to high sulfate properties of CT45 coating is better than LQG1000 coating,more suitable for power plant boiler water-cooled wall anti-corrosion application.The results showed that the CT45,LQG1000 oxidation mode function of the reductive atmosphere of sulfate in the high-temperature corrosion test is f(a)＝3(1-a)2 3/2[1-(1-a)1 3].