Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom.
Anal Chem. 2012 Jun 5;84(11):4866-72. doi: 10.1021/ac300457e. Epub 2012 May 17.
We have developed and tested two complementary methods for making time-lapse synchrotron X-ray diffraction (XRD) measurements of the growth of synthetic corrosion layers using a protocol for producing copper(I) chloride (nantokite), on copper as a test. In the first method, a copper coupon was spin-coated with saturated copper(II) chloride solution in air while the surface was characterized in real time using XRD with a fast one-dimensional (1-D) detector. In the second, a droplet of the same reagent was suspended from an X-ray-transparent window in a hermetically sealed cell and the coupon was brought into contact with this while XRD diffractograms were acquired with a charge-coupled device (CCD) camera. The protocol is completed by a deionized water rinse, which was also studied. The XRD shows nantokite precipitation in solution as well as growth on the surface, but the end products were variable proportions of nantokite, cuprite (Cu(2)O), and paratacamite (Cu(2)(OH)(3)Cl). The latter two were observed forming in a reaction between the nantokite and the rinsing water. Comparisons between samples analyzed in the synchrotron and at lower power densities show that the effects of any radiolysis or slight heating of the sample are insignificant in this case. It would be simple to extend these methods to other corrosion or surface reaction systems.
我们开发并测试了两种互补的方法，用于通过铜作为测试的铜（I）氯化物（纳米钛矿）的生产方案，对合成腐蚀层的生长进行时移同步加速器 X 射线衍射（XRD）测量。在第一种方法中，铜试片在空气中用饱和的二价铜（II）氯化物溶液旋涂，同时使用快速一维（1-D）探测器实时对表面进行 XRD 特征分析。在第二种方法中，同一试剂的液滴滴在密封腔室的 X 射线透明窗上，当 XRD 衍射图谱用电荷耦合器件（CCD）相机获取时，将试片与该液滴接触。该方案由去离子水冲洗完成，也对其进行了研究。XRD 显示纳米钛矿在溶液中的沉淀以及表面的生长，但最终产物是纳米钛矿、氧化铜（Cu2O）和副氯铜矿（Cu2（OH）3Cl）的不同比例混合物。后两者是在纳米钛矿与冲洗水之间的反应中形成的。在同步加速器和较低功率密度下分析的样品之间的比较表明，在这种情况下，任何辐射分解或样品的轻微加热的影响都微不足道。将这些方法扩展到其他腐蚀或表面反应系统将非常简单。
