Aubakirova Veta, Farrakhov Ruzil, Sharipov Arseniy, Polyakova Veronika, Parfenova Lyudmila, Parfenov Evgeny
Department of Electronic Engineering, Ufa State Aviation Technical University, 12 Karl Marx Street, 450008 Ufa, Russia.
Institute of Physics of Advanced Materials, Ufa State Aviation Technical University, 12 Karl Marx Street, 450008 Ufa, Russia.
Materials (Basel). 2021 Dec 21;15(1):9. doi: 10.3390/ma15010009.
The problem of the optimization of properties for biocompatible coatings as functional materials requires in-depth understanding of the coating formation processes; this allows for precise manufacturing of new generation implantable devices. Plasma electrolytic oxidation (PEO) opens the possibility for the design of biomimetic surfaces for better biocompatibility of titanium materials. The pulsed bipolar PEO process of cp-Ti under voltage control was investigated using joint analysis of the surface characterization and by in situ methods of impedance spectroscopy and optical emission spectroscopy. Scanning electron microscopy, X-ray diffractometry, coating thickness, and roughness measurements were used to characterize the surface morphology evolution during the treatment for 5 min. In situ impedance spectroscopy facilitated the evaluation of the PEO process frequency response and proposed the underlying equivalent circuit where parameters were correlated with the coating layer properties. In situ optical emission spectroscopy helped to analyze the spectral line evolutions for the substrate material and electrolyte species and to justify a method to estimate the coating thickness via the relation of the spectral line intensities. As a result, the optimal treatment time was established as 2 min; this provides a 9-11 µm thick PEO coating with Ra 1 µm, 3-5% porosity, and containing 75% of anatase. The methods for in-situ spectral diagnostics of the coating thickness and roughness were justified so that the treatment time can be corrected online when the coating achieves the required properties.
作为功能材料的生物相容性涂层性能优化问题需要深入了解涂层形成过程；这使得新一代可植入装置的精确制造成为可能。等离子体电解氧化（PEO）为设计具有更好生物相容性的钛材料仿生表面提供了可能性。通过对表面表征进行联合分析，并采用阻抗谱和光发射光谱的原位方法，研究了纯钛在电压控制下的脉冲双极PEO工艺。利用扫描电子显微镜、X射线衍射、涂层厚度和粗糙度测量来表征5分钟处理过程中表面形态的演变。原位阻抗谱有助于评估PEO工艺的频率响应，并提出了潜在的等效电路，其中参数与涂层性能相关。原位光发射光谱有助于分析基底材料和电解质物种的光谱线演变，并通过光谱线强度关系证明了一种估计涂层厚度的方法。结果，确定最佳处理时间为2分钟；这可提供一层厚度为9 - 11 µm、粗糙度为Ra 1 µm、孔隙率为3 - 5%且含有75%锐钛矿的PEO涂层。涂层厚度和粗糙度的原位光谱诊断方法得到了验证，这样当涂层达到所需性能时，可以在线校正处理时间。
