The behaviour of lead as a corrosion resistant medium undersea and in soils

Lead is a highly corrosion resistant metal in some environments and an attempt has been made to show its strength and weakness under long-term corrosion in land and marine conditions by means of examples taken from archaeological contexts. Some analyses and thicknesses are given of the corrosion films found on them. The importance of fine grain size and the role of certain impurities in obtaining this may be one reason why the older leads are often more resistant than modern leads.     

青铜合金表面晶体棱角处优先生锈的量子力学证明

在扫描电镜（SEM）观察青铜合金粉状锈生长过程的基础上,应用局部密度泛函（LDF）和电场梯度（EFG）方法,分别计算了σ－Cu－Sn和α－Cu一Sn合金晶体表面上原子的能级,并计算了各合金相的体相凝聚能;而后又分别计算了这四种相应情况的化学吸附活化能和化学反应活化能。由活化能的比较得出;晶体棱角上的Cu原子比平直表面上Cu原子的化学反应性能更活泼,因此生锈应首先发生在晶体棱角上;在同种位置上属于σ相的Cu原子又比α相中的Cu原子更活泼,因此在含有Cl-离子的酸性溶液中首先被锈蚀的是-σ相,而产生晶间腐蚀。上述计算与实验观察结果一致。     

青铜粉状锈生长过程的跟踪观测

在自制Cu－Sn－Pb合金表面施加腐蚀液,分别采用扫描电镜,透射电镜,红外反射光谱,红外光声光谱和显微光密度放大等仪器分析技术,跟踪观察粉状锈的生长发展过程。发现：锈蚀首先从表面棱角处发生;Cu首先生成一价锈CuCl,然后继续氧化生成二价锈Cu2（OH）3Cl;初期形成的粉状锈颗粒度极细,仅为纳米量级;常温下生锈速度十分迅速,因此粉状锈对青铜器的破坏性极大。文章对所观测到的现象进行了讨论,对锈体粒子大小及生长速度作了半定量分析。     

Damage assessment and conservation strategy for the largest covered market in Europe: the Ribera Market (Bilbao)

Facing a scarcity of land for urban development and demand for public services, the Municipal Council of Bilbao recognizes the need to make good use of its built heritage and to upgrade it, while maintaining its cultural and functional features. A good example is the case of the Ribera Market, the largest covered market in Europe. Deterioration of the market building and public pressure for improved services has led to proposals for its rehabilitation. To do so, the constructive condition of the building must first of all be assessed and, then, the most appropriate and compatible intervention technique must be selected. Today, there is a broad selection of intervention technologies, for the improvement of both mechanical behaviour and durability. However, in this article, it is demonstrated that these technologies are not always applicable in old buildings, because they depend on the severity of the pathology and the intrinsic characteristics of the building: for example, corrosion due to chloride ions originating from the concrete mass. The lack of knowledge on constructive techniques and the requirements for the application of new technologies complicate the interventions, which in turn further complicates decision-making with regard to the property.     

An Analytical Methodology for the Study of the Corrosion of Ferrous Archaeological Remains in Soils

Abstract

In the context of the cultural heritage, a methodology based on ?eld and laboratory approaches is developed for studying the long-term corrosion of iron. Moreover it has been adapted to the study of archaeological artefacts buried in anoxic soils in the speci?c case of in situ preservation. The environmental parameters are determined on the archaeological sites and artefacts are collected and characterized using complementary multi-scale techniques. Moreover, laboratory experiments are performed to locate the reaction sites inside the corrosion layer and to identify its electronic properties. The results allow estimation of a low corrosion rate for iron buried in an anoxic soil (under 2 μm/year) and the proposal of a mechanism based on a decoupling of the anodic and the cathodic sites. Then a diagnosis of the alteration state of the samples is established.     

几种罕见的黄铜钱币锈蚀产物的识别与形成原因探析

我国从明中期开始使用黄铜钱币,一直到清末。过去,对古代铸币的科学研究主要集中于合金成分分析和铸造工艺两方面,对锈蚀产物和锈蚀机理的研究主要针对青铜铸币。黄铜的合金元素中较青铜多锌元素,其腐蚀产物与腐蚀行为较青铜有一定的差别,也较青铜更为复杂,然而现有的文献关于此方面的研究匮乏,特别是对于大气保存环境下黄铜钱币的锈蚀产物及锈蚀成因的研究基本空白。本研究通过多种分析手段包括X射线荧光分析仪(XRF)、扫描电镜能谱仪(SEM-EDS)和显微激光拉曼光谱仪(Raman)对国家博物馆馆藏一批传世明清各时期的黄铜钱币合金组成,不同颜色的锈蚀产物等开展科学分析。研究结果表明,嘉靖、隆庆和万历年的黄铜铸币,为Cu+Sn+Pb+Zn四元合金,平均含量Cu 66.4%,Sn 6.8%,Pb 10.4%,Zn 15.6%,并含有微量Fe,不含As。泰昌、天启和崇祯年间及清代各时期的黄铜铸币,主要为Cu+Pb+Zn三元合金,并含有微量Fe、As和Sn。这批黄铜锈蚀产物与常见的青铜锈蚀产物不同,最典型的是钱币表面蓝绿色和白色锈蚀物,经Raman和SEM-EDS分析并结合相关文献初步确认蓝绿色锈蚀物为一种含铜、钠...     

银器文物的变色原因及防变色缓蚀剂的筛选

为探讨银器物变色的原因与防变色缓蚀剂的筛选研究,用极化曲线法对目前已知的多个银缓蚀剂进行缓蚀性能评价。筛选出较优良的银缓蚀剂为：2-巯基苯并恶唑(MBO)、1-苯基-5-巯基四氮唑(PMTA)、2-巯基苯并咪唑(MBI)等。这对银器物保护有较大的实用价值。     

几枚传世花纹钢剑的初步考察

本文主要介绍了数枚传世花纹钢剑的外部形态和花纹特征,并对其制作年代作了一些推测.这些剑的基本特点是表面带有自然花纹和难锈难蚀.花纹的基本形态有旋罗纹、半罗纹、斗箕纹、组丝纹、搅丝纹等;花纹的颜色有金黄色、银白色、浅灰色、褐黄色等.从多方面情况推测,它们很可能是元代生产的,最初的主人应是直接掌管花纹钢生产的政府官员.其中的许多工艺今已失传.类似的花纹钢剑以往尚未见于报道,国内学者的有关研究亦鲜.     

绿漆古铜镜的结构成分分析

运用 SEM,XPS,EPMA,Micro-XRD,IR 及 AAS 等仪器分析手段对两块绿漆古铜镜进行了结构成分分析。结果表明,在铜镜表面层中,Sn、Si 的元素含量远高于合金基体内部;表面层下的过渡层内有 O、C、Cl、P 等生锈元素,并有明显被腐蚀痕迹。文章对表面层下的生锈途径进行了探讨;对绿漆古铜镜的特殊成因进行了探索。古铜镜表面加工过程进行的推测,对青铜文物保护有一定参考价值。     

青铜病的发生与小孔腐蚀的关系

青铜病的产生与青铜器铸件本身的缺陷所产生的小孔腐蚀有一定的关系,小孔腐蚀可以解释青铜病的腐蚀现象。根据小孔腐蚀的特征,采用激振除锈垢和化学溶液相结合的方法,可以提高对青铜病的处理效果。进一步深入对小孔腐蚀的研究是解决青铜病问题的方向。