The high-temperature corrosion behaviors of HR3C pre-coated Na2SO4-25%NaCl salt film at 650 ℃ and 750 ℃ are investigated by means of X-ray diffraction(XRD), scanning electron microscope(SEM), energy dispersive spectrometer(EDS) and electron probe X-ray micro-analyser(EMPA). The results show that the corrosion kinetic curves of HR3C at 650 ℃ and 750 ℃ reveal the parabolic growth law. The corrosion products are mainly composed of Cr/Fe oxides, minor compound oxides with spinals structure as well as (Fe,Ni)xSy. Improving the corrosion temperature or prolonging the corrosion time, the oxide films in thickness increase significantly and the adjacent with the substrate is worse and seriously peeled off the surface, moreover, the pore densities among the corrosion affected zone (the interface between the oxide films and the matrix) increase. It is concluded that the high temperature corrosion of HR3C pre-coated Na2SO4-25%NaCl salt film is dominated by the interaction of oxidation, sulfidation and chlorination and Cl- is more detrimental than SO42- to HR3C. In the early stage of corrosion, high temperature oxidation occurred on the surface of the alloy and formed the oxide layers which had protective effect. The chlorination reaction promoted the fluxing of the mixed salt film as well as the formation of the volatile products, which destroyed the compact oxide layers. In addition, the vulcanization accelerated the occurrence of the alloy sulfide.
LI Ping
,
QIN Peng
,
ZHAO Jie
,
LI Tingju
,
PANG Shengjiao
. High Temperature Corrosion Behaviors of HR3C Steel Pre-coated Na2SO4-25%NaCl Salt Film[J]. Journal of Mechanical Engineering, 2016
, 52(8)
: 104
-111
.
DOI: 10.3901/JME.2016.08.104
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