植酸修饰改性对TC4钛合金微弧氧化膜层性能的影响

Effect of Phytic Acid Modification on Characteristics of MAO Coating on TC4 Titanium Alloy

摘要:

通过向电解液中添加有机酸植酸，提升了TC4钛合金微弧氧化涂层的耐腐蚀性能和热稳定性。通过扫描电子显微镜、X射线衍射仪、X射线光电子能谱仪和热冲击实验等技术手段，分析了植酸对涂层形成、形貌和性能的影响。结果显示，植酸的添加使放电微孔更加细小，提高了涂层的形成效率并优化了相结构。通过动电位极化测试，发现添加植酸显著提高了微弧氧化涂层的耐腐蚀性能。将电解液中的植酸浓度调整为12 mL/L（最佳植酸浓度）后，腐蚀电流密度由8.406×10^-5 A·cm^-2降低至2.580×10^-6 A·cm^-2。循环高温氧化试验结果表明，TC4钛合金的耐热冲击性能和高温抗氧化性能得到了改善。

Abstract:

Phytic acid, one kind of organic acid, was added into the electrolyte to enhance the corrosion performance and thermal stability of micro-arc oxidation (MAO) coating on TC4 titanium alloy. The effect of phytic acid on the coating formation, morphology, and performance was analyzed by scanning electron microscope, X-ray diffractometer, X-ray photoelectron spectroscope, and thermal shock experiments. Results show that the addition of phytic acid leads to the refinement of discharge microholes and improves the formation efficiency and phase structure of MAO coating. Through potentiodynamic polarization tests, it is found that adding phytic acid can significantly enhance the corrosion resistance of MAO coating. The corrosion current density decreases from 8.406×10^-5 A·cm^-2 to 2.580×10^-6 A·cm^-2 when the phytic acid concentration in electrolyte changes to 12 mL/L (optimal phytic acid concentration). Cyclic high temperature oxidation test results indicate that the thermal shock resistance and high temperature oxidation resistance of TC4 alloy are enhanced.