Effect of deposition of NaCl on the initial atmospheric corrosion of Q235

The influence of NaCl on the initial atmospheric corrosion of Q235 steel in simulated atmospheric environment including 5 × 10^-6 (volume) SO₂ and 1% (volume) CO₂ are investigated by mass gain, SEM and X-ray diffraction techniques. The results show that Q235 steel suffer a serious corrosion under the cooperative effect of NaCl, CO₂ and SO₂. It proved that the cooperative effect of SO₂ and CO₂ is important for the corrosion aggravating of Q235 steel when the NaCl is existed. The presence of NaCl accelerated and catalyzed the reaction of initial stage of atmospheric corrosion for carbon steel. The mass gain in the presence of NaCl was near decuple higher than that in the absence of NaCl. The corrosion products mainly are Fe₃O₄, γ - Fe₂O₃ and γ - FeOOH.