Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA.
Acta Biomater. 2010 Jun;6(6):2264-73. doi: 10.1016/j.actbio.2009.12.002. Epub 2009 Dec 5.
A series of functionally graded hydroxyapatite (FGHA) coatings incorporated with various percentages of silver were deposited on titanium substrates using ion beam-assisted deposition. The analysis of the coating's cross-section using transmission electron microscopy (TEM) and scanning transmission electron microscopy equipped with energy dispersive X-ray spectroscopy has shown a decreased crystallinity as well as a distribution of nanoscale (10-50nm) silver particles from the coating/substrate interface to top surface. Both X-ray diffraction and fast Fourier transforms on high-resolution TEM images revealed the presence of hydroxyapatite within the coatings. The amount of Ag (wt.%) on the outer surface of the FGHA, as determined from X-ray photoelectron spectroscopy, ranged from 1.09 to 6.59, which was about half of the average Ag wt.% incorporated in the entire coating. Average adhesion strengths evaluated by pull-off tests were in the range of 83+/-6 to 88+/-3MPa, which is comparable to 85MPa for FGHA without silver. Further optical observations of failed areas illustrated that the dominant failure mechanism was epoxy failure, and FGHA coating delamination was not observed.
采用离子束辅助沉积技术，在钛基体上沉积了一系列不同银含量的梯度羟基磷灰石（FGHA）涂层。使用透射电子显微镜（TEM）和配备能量色散 X 射线光谱仪的扫描透射电子显微镜对涂层截面进行分析，结果表明涂层的结晶度降低，从涂层/基体界面到表面分布着纳米级（10-50nm）的银颗粒。X 射线衍射和高分辨率 TEM 图像的快速傅里叶变换都表明涂层中存在羟基磷灰石。从 X 射线光电子能谱得出，FGHA 外表面的 Ag（wt.%）含量在 1.09 到 6.59 之间，约为整个涂层中平均 Agwt.%的一半。通过剥离试验评估的平均结合强度在 83+/-6 到 88+/-3MPa 范围内，与不含银的 FGHA 的 85MPa 相当。对失效区域的进一步光学观察表明，主要失效机制是环氧失效，未观察到 FGHA 涂层分层。
