硝酸镧对16Mn钢锌-锰系磷化膜耐蚀性的影响  

Effect of lanthanum nitrate on corrosion resistance of zinc-manganese phosphate films on 16Mn steel

作　　者：吴宝程 吴涛 王艺 Wu Baocheng;Wu Tao;Wang Yi(Qinghai Industrial Technician College,Xining 810000,China;Capital Construction Project Center of No.4 Oil Production Plant of Petro China Qinghai Oilfield Company;School of New Energy and Materials,Southwest Petroleum University)

机构地区：[1]青海省工业技师学院,青海西宁810000 [2]中国石油青海油田分公司采油四厂基建项目中心 [3]西南石油大学新能源与材料学院

出　　处：《无机盐工业》2021年第9期72-75,82,共5页Inorganic Chemicals Industry

基　　金：中石油工程技术攻关项目(ZD30251731);国家自然科学基金项目(51276199)。

摘　　要：为提高16Mn钢的耐蚀性,使用添加了硝酸镧的磷化液在16Mn钢表面制备锌-锰系磷化膜,并研究硝酸镧质量浓度对磷化膜的物相组成、表面形貌和耐蚀性的影响。结果表明:硝酸镧对磷化膜的物相组成基本没有影响,但会改变磷化膜表面的平整度和致密性,从而影响其耐蚀性。适当增加硝酸镧质量浓度,使磷化膜表面趋于平整致密,耐蚀性逐步提高。但是,硝酸镧质量浓度过高时磷化膜表面粗糙、致密性降低,导致耐蚀性下降。硝酸镧质量浓度为50 mg/L时制备的磷化膜电荷转移电阻、频率为0.01 Hz的阻抗值以及液滴变色时间均最大,分别达到5.028×10^(2)Ω·cm^(2)、3.12×10^(3)Ω·cm^(2)、186 s,表现出较好的耐蚀性,优于其他磷化膜。原因归结为,适量的硝酸镧可以加快成膜速度,有利于形成紧致密实的磷化膜,具有较强的阻挡腐蚀介质侵蚀能力,从而有效提高16Mn钢的耐蚀性。Zinc-manganese phosphate films were prepared on 16Mn steel from the phosphating solution containing lanthanum nitrate in order to improve the corrosion resistance of 16Mn steel,and the effect of mass concentration of lanthanum nitrate on the phase composition,surface morphology and corrosion resistance of phosphate films was studied.The results showed that lanthanum nitrate had almost no effect on the phase composition of phosphate films,but it could change the flatness and density of phosphate films,thus affecting the corrosion resistance.Appropriately increasing the mass concentration of lanthanum nitrate made the surface of phosphating films tend to be smooth and compact,and the corrosion resistance was gradually improved.However,when the mass concentration of lanthanum nitrate was too high,the surface of phosphating films was rough and the denseness reduced,resulting in the decrease of corrosion resistance.When the mass concentration of lanthanum nitrate was 50 mg/L,the as-prepared phosphate film had maximum charge transfer resistance,resistance value at frequency of 0.01 Hz and discoloration time of droplet,which was 5.028×10^(3)Ω·cm^(2),3.12×10^(3)Ω·cm^(2)and 186 s respectively.This phosphate film exhibited better corrosion resistance than that of other phosphate films,the reason was that appropriate amount of lanthanum nitrate could accelerate the film forming rate,which was conducive to the formation of tight and compact phosphate film,and had strong ability to resist the erosion of corrosive media,thus effectively improved the corrosion resistance of 16Mn steel.

关 键 词：锌-锰系磷化膜 耐蚀性 硝酸镧 电化学阻抗谱 表面形貌 

分 类 号：TB43[一般工业技术]