Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
Department of Materials Engineering, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
J Struct Biol. 2013 Sep;183(3):404-411. doi: 10.1016/j.jsb.2013.07.013. Epub 2013 Aug 6.
Nacre tablets from the shell of Pinctada maxima were studied with SEM, TEM and STEM. The systematic nanolath morphology on the (001) surface of nacre tablets was observed after acidic etching and mechanical polishing. The nanolaths were along the [100] crystallographic orientation of aragonite crystal. The (010) and (100) cross section surfaces of the nacre tablets showed nanolath and nanograin morphologies, respectively, which was consistent with [100] crystallographic orientation of nanolath on the (001) surface. Sheet-like defects with low mass density were observed on the (001) plane inside nacre tablets and were considered to be the cause of nanolath morphology revealed on the surfaces by acidic etching and mechanical polishing. On the other hand, large block [110] twins that divide the nacre tablets into two sectors were identified. The implication of these twins on the understanding to the crystallization mechanism of nacre tablets was discussed.
采用扫描电子显微镜（SEM）、透射电子显微镜（TEM）和扫描透射电子显微镜（STEM）对来自大珠母贝（Pinctada maxima）贝壳的珍珠层薄片进行了研究。经过酸蚀和机械抛光后，观察到珍珠层薄片（001）表面上具有系统性的纳米片形貌。纳米片沿文石晶体的[100]晶向排列。珍珠层薄片的（010）和（100）横截面表面分别呈现纳米片和纳米晶粒形貌，这与（001）表面上纳米片的[100]晶向一致。在珍珠层薄片内部的（001）面观察到具有低密度质量的片状缺陷，被认为是酸蚀和机械抛光后表面上纳米片形貌的原因。另一方面，鉴定出将珍珠层薄片分成两个扇区的大块状[110]孪晶。讨论了这些孪晶对理解珍珠层薄片结晶机制的意义。
