等离子体电解氧化陶瓷层生长动力学机制及力学特性

等离子体电解氧化(PEO)作为近年发展的"绿色"表面加工新方法,可有效提升轻金属材料的表面性能,在全铝发动机及纺织零部件等表面陶瓷化方面具有重要的实用价值。PEO过程为典型多效应耦合的极端非平衡过程,等离子体放电及涂层生长机理异常复杂,故存在多种诠释陶瓷层生长机制的理论模型;本文系统讨论了电子雪崩效应导致击穿放电的三个重要模型,即Ikonopisov模型,连续雪崩模型和杂质中心放电模型。由于火花放电及高温烧结作用,PEO过程中存在氧化膜的击穿、熔化、凝固及相变等反应,并最终形成具有微孔结构的陶瓷性涂层。陶瓷层中微孔密度及孔隙特征与其服役性能紧密相关,因此文中阐述了PEO陶瓷层孔隙率的测定方法,并总结了PEO涂层的抗疲劳特性及其摩擦磨损行为。此外,提出了等离子体电解氧化的研究重点与发展方向,展望了该新方法的应用领域与广阔前景。

Synthesis and luminescence properties of hybrid organic-inorganic transparent titania thin film activated by in-situ formed lanthanide complexes

Stable transparent titania thin films were fabricated at room temperature by combining thenoyltrifluoroacetone (TTFA)-modified titanium precursors with amphiphilic triblock poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO, P123) copolymers. The obtained transparent titania thin films were systematically investigated by IR spectroscopy, PL emission and excitation spectroscopy and transmission electron microscopy. IR spectroscopy indicates that TTFA coordinates the titanium center during the process of hydrolysis and condensation. Luminescence spectroscopy confirms the in-situ formation of lanthanide complexes in the transparent titania thin film.