The Corrosion Of20G In Titanium Sponge Reaction Pool Fluid

In industry, the most commonly used method to produce titanium sponge is to use theMg thermal reduction process, in a TiCl4Mg reaction, Mg reacts with TiCl4and comes outas liquated MgCl2. MgCl2will corrode the boiler inevitably.This topic is to investigate service life and protection of boiler steel20G by thecorrosion of liquated MgCl2in850℃and900℃. calculating weightlessness value perunitarea, analyzing phase composition on the corrosion surface by using XRD, doingmicrostructure observation and composition analysis by using scanning electronmicroscopy (SEM) and energy spectrometer can conclude the corrosion characteristics ofthe20G in two temperatures.The experimental results show that the corrosion of liquated MgCl2in20G can causeweightlessness and surface oxidation film is mainly composed by MgO. There is no Cl-inthe corrosion layer and Si element can flow out of the corrosion layer easily. Whencorroding in900℃,Mg and Mn can combine to generate Mg0.9Mn0.1at the beginning. Withthe increase of corrosion time, C in the corrosion layer can be oxidized because of theintervention of O2in the air. Mg0.9Mn0.1could turn into Mg2MnO4�'�Mg6MnO8after all theC in the corrosion layer has been gone. When corroding from40h to70h, structure andcomposition change a lot and there are only Fe、Fe0.25Mn1.4C0.6and MgO in the corrosionlayer. Steel piece has a logarithmic weightlessness curve when corroding. In the early stageof the corrosion, steel piece has a thinner corrosion layer and faster corroding speed anddissolved weightlessness. Corroding speed is highest from8h to20h. Corrosion layer isthick and stable after corroding70h. When corroding in850℃,composition of thecorrosion layer is relatively stable and Fe、MgO、FeMn4、Mg0.9Mn0.1、Mg2MnO4�'�Mg6MnO8have always been existent. Thickness of the corrosion layer increase before20hand decreases after then. Fe external diffusion out of the MgO corrosion layer makes weightlessness. Diffusion behavior has been slown down because of the thicking corrosionlayer that corroding speed turns slow. Weightlessness in850℃is far more less than itis in900℃.