五种含氯铜合金腐蚀产物的拉曼光谱及扫描电镜的分析研究

为深入研究五种含氯铜合金腐蚀产物(氯铜矿、斜氯铜矿、羟氯铜矿、氯磷钠铜石和铜氯矾)的拉曼光谱图,进一步补充金属锈蚀物的拉曼光谱库,采集不同考古来源的铜合金上腐蚀产物的拉曼光谱,并结合扫描电镜观察了腐蚀产物的形貌特征。研究结果表明,氯铜矿、斜氯铜矿和羟氯铜矿3个同分异构体的拉曼光谱并不相同:氯铜矿和斜氯铜矿较为常见,且经常混合在一起;羟氯铜矿不稳定,非常少见,一般与其他两种混合在一起。扫描电镜观察氯铜矿主要为粒状形貌,同时也发现有葡萄状、皮壳状、钟乳状等形貌;羟氯铜矿因少见,目前只观察到板状形貌。氯磷钠铜石腐蚀产物较厚且疏松柔软,常发现于干旱地区有动物或人遗骸墓葬的出土器物上,扫描电镜观察呈花瓣形状的蓓蕾形貌。铜氯矾更为少见,笔者目前只在2件器物上发现。同时对5种腐蚀产物的形成原因进行了讨论。

Study of five chloride-containing corrosion products from copper and bronze artifacts using Raman spectroscopy and scanning electron microscopy

Raman spectroscopy is a very powerful tool for identifying the corrosion products of copper alloys. In our study, the Raman spectra of five chloride-containing corrosion products (atacamite, clinoatacamite, botallackite, sampleite and connellite) from ancient bronze and copper objects were obtained, and the morphology of corrosion products was observed with the aid of scanning electron microscopy (SEM). The results show that the Raman spectra of atacamite, clinoatacamite and botallackite (they are isomeric substances) are different. Atacamite and clinoatacamite are more commonly-seen and often mixed together.Scanning electron microscopy reveals that atacamite is mainly granular morphologically, although grape-like, crustacean-like and stalactitic ones have also been found. Botallackite is very rare because of its instability, and is generally mixed with the other two. Currently it has only been observed in the shape of plates. Sampleite corrosion products are thick, loose and soft, often found on bronze objects in arid areas or from tombs with animal or human remains. The SEM photomicrograph shows a form of closed buds with multiple petal-like crystal components. Connellite is even rarer and has only been detected on two objects. The reasons for the formation of five corrosion products are also discussed in this paper.