热镀锌层对Q235钢在模拟混凝土碱性环境中的保护作用  

Protective Action of Hot-Dipped Galvanizing Coating for Q235 Steel Substrate in Alkaline Environment of Simulated Concrete

作　　者：王剑[1] 游革新[1] 王婧[1] 刘钧泉[1] 

机构地区：[1]华南理工大学机械与汽车工程学院,广东广州510640

出　　处：《材料保护》2012年第7期4-6,73,共3页Materials Protection

摘　　要：为了探知DN25热镀锌钢管热镀锌层对Q235管材的保护作用,对比测量了不同模拟混凝土介质中Q235钢热镀锌前后的电极电位和两者间的电偶电流,从热力学和动力学方面判断镀锌层对Q235钢的保护作用。结果表明:在NaCl中性溶液及pH=10.0～13.0 Ca(OH)2溶液中,热镀锌层对Q235钢均有牺牲阳极的保护作用;在含Cl-模拟混凝土饱和Ca(OH)2碱性溶液[Ca(OH)2+NaCl,pH值为12.5]中,镀锌后的电极电位和电偶电流均波动较大,其电极电位比镀锌前的负,大部分时间内镀锌后流过的是阳极电流,某些瞬间镀锌前后间的电偶电流会发生逆转。The electrode potentials of Q235 steel and its hot-dipped galvanizing coating as well as the galvanic current between the steel substrate and the galvanizing coating in different alkaline environments of simulated concrete were measured and compared. The protective action of the galvanizing coating for the steel substrate was investigated in relation to thermodynamics and kinetics. Results show that, in neutral solution of NaCl and Ca(OH)2 solutions with pH values of 10.0, 11.0, 12.0, 12.5, and 13.0, hot-dipped galvanizing coating as the sacrificed anode is able to well protect the steel substrate. In the alkaline solutions of Ca(OH)2 saturated by the simulated concrete containing Cl-, both the electrode potential and galvanic current of the hot-dipped galvanizing coating fluctuate greatly. Besides, the electrode potentials of hot-dipped galvanizing coating are always more negative than those of the steel substrate. The currents flowing through the hot-dipped galvanizing coating are usually anodic currents, but the galvanic currents between the hot-dipped galvanizing coating and steel substrate may inversely change direction sometimes.

关 键 词：热镀锌层 模拟混凝土介质 电极电位 电偶电流 Q235钢 保护作用 

分 类 号：TG174.44[金属学及工艺—金属表面处理]