CAJ | 학술논문

采用硝酸亚铈、六偏磷酸钠组成的转化液，在镀锌钢表面制备了铈盐转化膜，研究了硫化钠(Na2S)对其耐蚀改性作用。通过中性盐雾(NSS)试验考察了Na2S质量浓度、pH、温度、时间等工艺条件对转化膜耐蚀性的影响，通过单因素试验得到最佳转化条件为：Na2S 6 g/L，温度25°C，pH 0.8，转化时间3 min。用扫描电镜和能谱分析了有无Na2S改性的铈盐转化膜的形貌结构及成分，用Tafel极化曲线法比较了它们的耐蚀性。结果表明，加入Na2S增强了铈盐转化膜与镀锌钢基体的附着力，提高了O、P、Ce等主要耐蚀成分的含量，耐盐雾腐蚀时间由改性前的24 h延长到改性后的96 h，耐蚀性显著提高。
채용초산아시、륙편린산납조성적전화액，재도자강표면제비료시염전화막，연구료류화납(Na2S)대기내식개성작용。통과중성염무(NSS)시험고찰료Na2S질량농도、pH、온도、시간등공예조건대전화막내식성적영향，통과단인소시험득도최가전화조건위：Na2S 6 g/L，온도25°C，pH 0.8，전화시간3 min。용소묘전경화능보분석료유무Na2S개성적시염전화막적형모결구급성분，용Tafel겁화곡선법비교료타문적내식성。결과표명，가입Na2S증강료시염전화막여도자강기체적부착력，제고료O、P、Ce등주요내식성분적함량，내염무부식시간유개성전적24 h연장도개성후적96 h，내식성현저제고。
A cerium salt conversion coating was prepared on galvanized steel in a bath mainly consisting of cerium(III) nitrate and sodium hexametaphosphate. The modification effect of sodium sulfide (Na2S) on corrosion resistance of the coating was studied. The influences of conversion conditions such as mass concentrations of Na2S, pH, temperature, and reaction time on corrosion resistance of the coating were studied by neutral salt spray (NSS) test. The optimal conditions were determined by single-factor experiment as follows: Na2S 6 g/L, temperature 25 C, pH 0.8, and time 3 min. The cerium-salt conversion coating obtained thereby was compared with the unmodified one. The surface morphology and elemental composition were analyzed by scanning electron microscopy and energy-disperse spectroscopy. The corrosion resistance was characterized by Tafel polarization measurement. The results showed that the addition of Na2S enhances the adhesion between the conversion coating and galvanized steel, and increases the contents of major anticorrosive components such as O, P, and Ce. The enduring time to NSS test of cerium-salt conversion coating prolongs from 24 h to 96 h after modification, showing an evident improvement of corrosion resistance.