Matykina E, Arrabal R, Skeldon P, Thompson G E
Corrosion and Protection Centre, School of Materials, The University of Manchester, Sackville Street, P.O. Box 88, Manchester M60 1QD, UK.
Acta Biomater. 2009 May;5(4):1356-66. doi: 10.1016/j.actbio.2008.10.007. Epub 2008 Oct 25.
Transmission electron microscopy and supporting film analyses are used to investigate the changes in composition, morphology and structure of coatings formed on titanium during DC plasma electrolytic oxidation in a calcium- and phosphorus-containing electrolyte. The coatings are of potential interest as bioactive surfaces. The initial barrier film, of mixed amorphous and nanocrystalline structure, formed below the sparking voltage of 180 V, incorporates small amounts of phosphorus and calcium species, with phosphorus confined to the outer approximately 63% of the coating thickness. On commencement of sparking, calcium- and phosphorus-rich amorphous material forms at the coating surface, with local heating promoting crystallization in underlying and adjacent anodic titania. The amorphous material thickens with increased treatment time, comprising almost the whole of the approximately 5.7-microm-thick coating formed at 340 V. At this stage, the coating is approximately 4.4 times thicker than the oxidized titanium, with a near-surface composition of about 12 at.% Ti, 58 at.% O, 19 at.% P and 11 at.% Ca. Further, the amount of titanium consumed in forming the coating is similar to that calculated from the anodizing charge, although there may be non-Faradaic contributions to the coating growth.
采用透射电子显微镜和支撑膜分析方法，研究了在含钙磷电解质中进行直流等离子体电解氧化时钛表面形成的涂层在成分、形态和结构方面的变化。这些涂层作为生物活性表面具有潜在的研究价值。在180V的火花电压以下形成的初始阻挡膜具有混合的非晶态和纳米晶态结构，含有少量的磷和钙物种，磷集中在涂层厚度约外63%的区域。在火花开始时，富含钙和磷的非晶态材料在涂层表面形成，局部加热促进了下层和相邻阳极二氧化钛的结晶。随着处理时间的增加，非晶态材料变厚，在340V形成的约5.7微米厚的涂层几乎全部由非晶态材料组成。在此阶段，涂层比氧化钛厚约4.4倍，近表面成分约为12原子%的Ti、58原子%的O、19原子%的P和11原子%的Ca。此外，形成涂层所消耗的钛量与根据阳极氧化电荷计算的量相似，尽管涂层生长可能存在非法拉第贡献。
