含铅黄铜儿童仿真饰品标准物质的研制

4介绍含铅黄铜儿童仿真饰品标准物质的研制方法。以铜锭、锌锭、铅粒为原料,利用坩埚熔炼及模具加工制备黄铜儿童仿真饰品标准物质,采用电感耦合等离子体发射光谱法进行均匀性检验、稳定性检验和定值。从样品中随机抽取15份进行均匀性检验,经F检验表明在95%的置信区间内样品均匀性良好。在常温条件下,经过12个月长期稳定性试验考察,结果表明样品稳定性良好。铅含量定值结果为136.1 mg/kg,合成扩展不确定度为0.72 mg/kg(k=2)。该标准物质满足ISO Guide 35:2006技术要求,可用于黄铜儿童仿真饰品检测的方法校正和质量控制。     

Comparison Between Different Methods of Analysis of Corrosion Products of Aluminum Brass in Sea Water: Chemical analysis,X-Ray Diffractometry,Auger Spectroscopy

Abstract

The oxidation layer formed on the surface of aluminum brass corroded in sea water at 40° C for 15 days was analysed by using different techniques (chemical analysis after selective dissolution, X-ray diffreactometry and Auger spectroscopy) and was found to be formed by Cu oxychlorides, basic Zn sulfates, Al and Mg Car bonates, Al oxides.

Chemical and diffractometric analyses yield an average value of the composition of the corrosion layer, whose thickness should be greater than 60-80° Å for chemical and than 100 Å for diffraacto metric analysis.

Auger speactroscopy permits the analysis of thin films and of small surface areas, and gives results that agree with those of the other two techniques when the corrosion layer is homogeneous.     

The void nucleation mechanism within lead phase during spallation of leaded brass

The incipient spall behaviours of Cu-34%Zn-3%Pb leaded brass samples with annealed and cryogenic-treated conditions were loaded using one-stage light gas gun experiments. The effect of Pb-phase on dynamic damage nucleation in leaded brass specimens was investigated by means of optical microscopy, scanning electron microscopy and x-ray computer tomography. It was found that the voids of incipient spall were mainly nucleated in the interior of the lead (no tensile stress would be produced within lead according to the impact theory) instead of nucleated at the phase interface as expected by quasi-static damage fracture theory. A nucleation model is proposed in the present work that is the asymmetry high compression zones in the centre of the lead-phase were formed by the rarefaction wave convergence effects of matrix/quasi-spherical lead interface, which caused adiabatic temperature rise that exceeded melting point of lead due to severe plastic deformation, finally led to local melting and void nucleation. In addition, the spall strength and damage rate increased with the increase in the Pb-phase number.     

测量线胀系数的一种新方法

给出测量金属线胀系数的一种新方法。本文根据夫琅和费衍射原理，利用CCD来测量金属体随温度升高的伸长量，对黄铜的线胀系数进行了测量。     

Spectral Dependencies of the Surface Photo-Charge Effect at Conducting Surfaces

Investigations show that the surface photo-charge effect has been observed for all solids. In this paper, experimentally obtained spectral dependencies of this effect at surfaces of several conductors (viz., Cu, Pb, Ag, brass,) are shown and discussed.     

稀土Ce对HMn64-8-5-1.5黄铜组织和磨损性能的影响

研究了稀土Ce元素对HMn64-8-5-1.5黄铜的组织和室温力学性能以及摩擦学性能的影响。结果表明:添加少量Ce对锰黄铜的物相构成影响较小,因此合金的力学性能变化范围较小。随着合金中Ce质量分数的增加,锰黄铜基体β相和硬质相的晶粒尺寸逐渐减小,而且硬质相的分布更加均匀弥散,材料的组织结构得到改善,从而提高材料的耐磨损性能。添加质量分数0.25%的Ce,材料的磨损速率减少约19%。在相同工况的干摩擦条件下,随着Ce质量分数的增加,HMn64-8-5-1.5黄铜的主要磨损形式逐步从较严重的疲劳剥层磨损和黏着磨损过渡为轻微的黏着磨损和氧化磨损。     

The combination of surface enhanced Raman spectroscopy and an ionic liquid as a model system to study the adhesion interface between sulfur and brass

The adhesion of steel cord to rubber is very important for the quality of reinforced rubber products, e.g. tyres. Therefore, steel cord is often plated with brass, which will lead to Cu_xS bonds after reaction with sulfur compounds in the rubber. A unique in‐situ analytical method has been developed to investigate the sulfur–brass interface: the sulfuring process has been simulated via a heating process in a water‐free transparent ionic liquid with added sulfur and the reaction at the brass‐coated steel cord has been monitored in real time with Raman spectroscopy. The grown Cu_xS film seems to be similar to the layers at the steel cord interface in real rubber materials. The model system can also be used to perform electrochemical measurements at the same time. The thickness of the Cu_xS layer has been estimated from the measured current during a cathodic stripping process. Copyright © 2013 John Wiley & Sons, Ltd.     

Annealing texture of a cold-rolled Fe–Mn–Al–Si–C alloy

The study of recrystallization texture of a cold deformed Fe–Mn–Al–Si–C alloy, with about 30% Mn, has been discussed in this paper. The alloy is fully austenitic at room temperature, and therefore, principal FCC rolling textures were developed in this material at different stages of cold rolling. The present study was undertaken to observe the transformation of FCC rolling texture during recrystallization of a heavily cold deformed specimen. It was observed that isothermal annealing at 750 °C led to a weak recrystallisation texture, which was quite similar to the deformation texture developed at the early stage of cold rolling. During recovery stage, a strong Bs/Goss-type texture was developed, which was identified as a new observation in this work.     

金相组织变化对X射线荧光光谱法测定黄铜中铜铅铁的影响及校正

研究了金相组织变化对X射线荧光光谱法测定黄铜中Cu、Pb、Fe的影响。Pb相和Fe相的出现使得Cu的测定结果偏高,Pb和Fe的校准曲线不成一条直线。金相组织的变化导致试样测量表面的元素分布不均匀,从而影响了元素间吸收和增强效应的实际效果,理论α影响系数不再适合校正基体效应。提出了4种数学方法来校正金相组织变化的影响：(1)理论α影响系数和经验影响系数相结合的方法;(2)根据析出相的比例校正校准曲线的斜率;(3)引入二次项校正;(4)根据Pb相的析出情况,以Pb含量0．6％为分隔点,对校准曲线分段。     

X‐ray,synchrotron, and neutron diffraction analysis of Roman cavalry parade helmet fragment

A partially corroded fragment of the neck guard of a Roman cavalry helmet excavated in the former military camp of Gerulata, a part of the Limes Romanus on the River Danube, was analysed by laboratory X‐ray, synchrotron and neutron powder diffraction. The approximate phase composition determined by the neutron diffraction of the bulk, 82% (wt) of the copper alloy phase, 12 % (wt) of cuprite and 6% of nantokite indicate a significant degree of corrosion of the artefact. Elemental EDX analysis of cleaned surface showed that the chemical composition of the original alloy is 78 to 82 % (wt) of Cu and 21.4 to 16.5 % of Zn with minute amounts of Sn, Si and S. High contents of Cu and Zn with the negligible amount of Sn showed that the body of the helmet was made of brass and not of bronze as expected before. The amount of zinc in the copper alloy calculated from the refined lattice parameter agrees fairly well with the value determined by EDX. The most abundant phase in the synchrotron powder diffraction pattern of the corrosion products scrapped from the artefact is cuprite, but presence of atacamite, malachite, brochantite, nantokite, mixed Cu‐Zn hydroxyl carbonates and probably also of simonkolleite (Zn₅(OH)₈Cl₂·H₂O) have been detected. In contrast, the X‐ray pattern taken directly from the surface of the artefact is dominated by atacamite with some traces of malachite and quartz. Because the penetration depth of laboratory X‐rays is in order of tens of microns, the phase analysis based only on a diffraction pattern taken from a surface can lead to erroneous conclusions concerning the phase composition of the patina. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)