Equipment Material Selection Against Feedstock Containing Chloride (2)

    In case of evaporators or crystallizers applied for treating feedstock containing chloride, the equipment material is suggested to be titanium due to strong corrosion of chloride. 

    In this article, the upper limit of service temperature of pure Ti, Ti-Pd alloy( Grade 7, TA9) and the Ti-Ni-Mo alloy (Grade 12,TA10) for magnesium chloride solution, sodium chloride solution and calcium chloride solution at different concentration are shown in the following figures. There would be crevice corrosion or pitting corrosion happens when the temperature exceeds the upper limit. 

    Note : in the figure, the white circles represent workable; the black circles represent crevice corrosion or pitting corrosion happening easily; the white triangles represent crevice carrion happening slightly but without affecting the the normal use.

    In MgCl2 solution:

    In CaCl2 solution:

    In NaCl solution:

    It can be get that the Pi-Pd alloy and Ti-Ni-Mo have better chlorine ion resistance than pure Ti: Pi-Pd alloy (Grade 7, TA9) > Ti-Ni-Mo (Grade 12, TA10) > Pure Ti（Grade 2, TA2）.