Intergranular corrosion of high temperature alloys in molten fluoride salts
Intergranular corrosion of high temperature alloys in molten fluoride salts
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DOI：
10.3184/096034010x12743509428336
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发表时间：
2010-06-01
影响因子：
1.3
通讯作者：
Allen, Todd
中科院分区：
文献类型：
--
作者：
Olson, Luke;Sridharan, Kumar;Allen, Todd
将6种Ni和Fe-Ni基奥氏体合金暴露在熔体LiF-NaF-KF:46.5-11.5-42 mol%的盐（通常称为FLiNaK）中，在850℃下加热500小时。腐蚀主要发生在铬的脱合金化导致空洞形成，这一效应在晶界处尤为明显。熔融氟化物盐腐蚀导致的合金重量损失与合金初始Cr含量相关，Cr含量约为20%，与腐蚀试验后盐中测量的Cr浓度一致。然而，在名义上含铬量为20 wt%至23 wt%的合金中，由于在晶界处形成碳化铬相并随后沿晶界溶解到熔盐中，这种失重与合金的碳含量呈线性相关。合金中发现的Cr-lean金属间析出物在熔融的FLiNaK盐中耐腐蚀。
Six Ni and Fe-Ni based austenitic alloys were exposed to molten LiF-NaF-KF:46.5-11.5-42 mol% salt, commonly referred to as FLiNaK, at 850 degrees C for 500 h. Corrosion was noted to occur predominantly from dealloying of Cr resulting in void formation, an effect that was particularly pronounced at the grain boundaries. Alloy weight-loss due to molten fluoride salt corrosion correlated with the initial Cr-content of the alloys up to a Cr content of about 20 wt%, and was consistent with the Cr-concentrations measured in the salts after corrosion tests. However, in the nominally 20 wt% to 23 wt% Cr containing alloys, this weight-loss correlated linearly with the carbon content of the alloys, due to the formation of chromium carbide phases at the grain boundaries and its subsequent dissolution into the molten salt along the grain boundaries. The Cr-lean intermetallic precipitates found in the alloys were resistant to corrosion in the molten FLiNaK salt.