生物质锅炉过热器用钢在混合碱金属熔盐中的电化学腐蚀行为

Electrochemical corrosion behavior of biomass boiler superheater steel in mixed alkali metal molten salts

以过热器12Cr1MoV钢为研究对象,在不同的混合碱金属熔盐中开展电化学腐蚀试验。结果表明:12Cr1MoVG钢在600、700℃KCl+NaCl熔盐腐蚀环境下的电化学阻抗谱表现出双容抗特征;电化学反应时间越长,阻抗谱的高频端阻抗值越大;在600℃条件下的阻抗值高于700℃下的阻抗值,随着温度的升高,12Cr1MoVG钢的腐蚀速率更大;在混合熔盐中12Cr1MoVG合金整体的腐蚀速率大小顺序为υ_(KCl+NaCl)>υ_(KCl+K_2SO_4)>υ_(KCl+Na_2SO_4)。

Taking 12CrlMoV superheater tube as research object, electrochemical corrosion test in different mixed alkali molten salt was carried out. The results show that the electrochemical impedance spectrum of 12CrlMoV steel in KC1 ＋ NaC1 mixed molten salt exhibits a double capacitance characteristics at 600 ℃ and 700 ℃. The longer the electrochemical reaction time, the higher the impedance value of the impedance spectrum. Impedance value at 600 ℃ is much higher than that at 700 ℃, and with the increasing of the molten salt temperature, the corrosion rate of 12CrlMoV steel becomes greater. Comparing different mixed alkali molten salts, the order of total corrosion rate of 12Crl MoV is VKC ＋ NaCl〉 13KCI ＋ K2SO4 〉 VKCI ＋ Na2SO4.