TiO2纳米颗粒对7075铝合金表面等离子体电解氧化涂层性能的影响

• 作 者: Mehri HASHEMZADEH Keyvan RAEISSI Fakhreddin ASHRAFIZADEH Amin HAKIMIZAD Monica SANTAMARIA
• 机 构: Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran;Yek
• 出 处: 中国有色金属学报（英文版）
• 发表日期: 2021年12期
• 关键词: Al alloy Al2O3?TiO2 coating plasma electrolytic oxidation potassium titanyl oxal

采用等离子体电解氧化(PEO)技术,利用单极脉冲波形在含有胶体TiO2纳米颗粒的溶胶电解液中制备Al2O3?TiO2复合涂层.溶胶溶液是将1、3和5 g/L的草酸钛酸钾(PTO)溶解在硅酸盐溶液中制得.利用扫描电镜、能量色散光谱、X射线衍射和拉曼光谱对涂层进行表征.采用极化和阻抗技术研究涂层的腐蚀行为.结果表明,TiO2通过微放电方式进入涂层,并掺杂到氧化铝相中.TiO2掺入量较高时,表面微孔减少;反之,掺入量较低时则微孔增多.TiO2含量越高,涂层的外层越致密,内层越厚.电化学测试结果表明,与在不含PTO溶液中制备的涂层相比,在含3 g/L PTO溶液中制备的涂层腐蚀性能得到大幅提高.在不含PTO溶液中制备的涂层含有γ-Al2O3,δ-Al2O3和非晶相,而PTO的存在促进α-Al2O3的生成.“,”Plasma electrolytic oxidation (PEO) was applied using a pulsed unipolar waveform to produce Al2O3?TiO2 composite coatings from sol electrolytic solutions containing colloidal TiO2 nanoparticles. The sol solutions were produced by dissolving 1, 3, and 5 g/L of potassium titanyl oxalate (PTO) in a silicate solution. Scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction, and Raman spectroscopy were applied to characterizing the coatings. Corrosion behavior of the coatings was investigated using polarization and impedance techniques. The results indicated that TiO2 enters the coating through all types of micro-discharging and is doped into the alumina phase. The higher level of TiO2 incorporation results in the decrease of surface micro-pores, while the lower incorporation shows a reverse effect. It was revealed that the higher TiO2 content makes a more compact outer layer and increases the inner layer thickness of the coating. Electrochemical measurements revealed that the coating obtained from the solution containing 3 g/L PTO exhibits higher corrosion performance than that obtained in the absence of PTO. The coating produced in the absence of PTO consists of γ-Al2O3, δ-Al2O3 and amorphous phases, while α-Al2O3 is promoted by the presence of PTO.