Choice of optimum conditions of emitter preparation for X-ray fluorescence analysis of aerosols

The nonuniformity of aerosol distribution over filter surface was studied. It was found that the distribution depends on the properties of the studied object and on the sampler type: particle concentration is often higher in the center of the filter, but in some cases, they shift to the edges; the uniform distribution of particles is observed rarely. It was shown that, if the emitter in X-ray fluorescence analysis (XRF) is a disk 3 cm in diameter cut from the center of a filter 5 cm in diameter, the systematic error of the results of analysis may be higher than 0.30. Recommendations on the choice of the conditions of sampling aerosols and emitter preparation are formulated. If these conditions are met, the results of XRF analysis of nonuniform filters are characterized by s_r = 0.05, which satisfies the admissible error.     

K金饰品中金含量的检测方法比对

目前实验室对金首饰金含量的主要检测方法为火试金法、X射线荧光光谱（XRF）法和电感耦合等离子体-原子发射光谱（ICP-AES）法.当测试结果出现争议时,国家标准GB 11887-2012中以火试金法作为仲裁方法.采用上述3种不同的金含量测试方法分别对14K、18K和22K饰品的金含量进行测定,并对3种方法检测结果进行比对.结果发现,在3种方法均可满足样品分析对准确度的要求时,以火试金法为基准,XRF法与ICP-AES法对同纯度的金首饰检测结果的相对误差差异较大,XRF法的结果可满足检测要求,而ICP-AES法的结果无法满足检测要求.其中,XRF法的相对误差为0.05%~0.77%,ICP-AES法的相对误差为1.24%~3.89%.从结果来看,低纯度的K金饰品使用XRF法的检测结果要更接近于火试金法.     

X射线反散射法测量塑料薄膜厚度

为实现快速、无损、精确的塑料薄膜厚度分析,讨论了XRF方法在塑料薄膜厚度测量中的应用,采用源初级射线散射法对塑料薄膜厚度进行相对测量。结果表明,厚度在10～800μm时,反散射X射线荧光强度与塑料薄膜厚度线性关系良好。对仪器标定后进行200 s快速测量,测量的厚度绝对误差<3μm(10～135μm),相对误差<4%(36～576μm),有较高的测量精度。XRF方法可用于塑料薄膜厚度的测量,该法对塑料工业的生产有现场指导的意义。     

The influence of scattering processes in quantitative X-ray fluorescence analysis

Existing theory was used to develop a fundamental parameter (FP) computer program for quantitative X-ray fluorescence (XRF) spectrometry in which scattering interactions are taken into account. The program is suited for polychromatic radiation and composite samples and is used to estimate the errors that result from neglecting the scattering contributions in the analysis of samples in a low Z matrix when the spectrometer is calibrated either on pure elements or on standards similar to the samples.     

金属材料分析国内外标准中波长色散X射线荧光光谱法的应用

对国内外金属材料分析方法标准(包括ASTM、JIS、EN和GB)中应用波长色散X射线荧光光谱法(XRF)的现状,从方法所涵盖的测定元素及其测定的含量范围以及谱线重叠和基体效应的校正等几个方面,并以钢铁分析中的应用为例作了评述。美国材料与试验协会在2012-2016年间先后发布了3个XRF标准方法,分别应用于铸铁、不锈钢、合金钢和低合金钢的分析,测定元素达13项,根据相关钢材的技术规格确定了各元素含量的测定范围。日本工业标准调查会于1997年并于2010年和2013年经修订公布了钢铁XRF分析法JIS标准,可测定各类钢材中主量、次量以及痕量元素达31项,其中镍、铁、钴和测定下限分别延伸至99.5%,50%和60%,从而使此方法有可能扩展应用于镍基、铁镍基和钴基高温合金的分析。我国先后于2007年和2018年由国家标准经主管部门颁布了XRF分析钢铁和高合金钢的两个标准,可测定这2类钢材中的元素为13项和11项,其测定含量范围系根据材料的技术规格确定。关于谱线重叠和基体效应的校正,各标准中在相关部分作了说明,而ASTM有两则独立标准专门论述这两个问题。在此评述对其他金属材料的XRF分析标准也作了介绍(引用文献15篇)。     

X射线荧光光谱法快速测定费托蜡中铁

通过对费托蜡(合成蜡、渣蜡)创新制样与装样、测试条件优化,利用仪器自带的基本参数法无标样半定量分析软件,建立了X射线荧光光谱(XRF)测定费托蜡中Fe的方法。测定的相对标准偏差<1%、典型分析时间10 min/样,无需标样。与ICP-AES测定结果相比较,相对误差低于10%,同时降低了蜡样测试对仪器真空度或分光晶体产生的不良影响。     

应用手持式XRF分析仪快速测定白铜中的Cu、Ni、Co含量

采用国产手持式XRF分析仪快速分析了白铜合金主元素的含量,探讨了白铜合金基体效应对测量结果的影响,采用经验系数法中多元回归分析建立数学模型,较好地校正基体效应,分析白铜合金中铜、镍、钴的平均相对误差分别为0.39%、1.83%、1.59%。     

Multilayers quantitative X-ray fluorescence analysis applied to easel paintings

X-ray fluorescence spectrometry (XRF) allows a rapid and simple determination of the elemental composition of a material. As a non-destructive tool, it has been extensively used for analysis in art and archaeology since the early 1970s. Whereas it is commonly used for qualitative analysis, recent efforts have been made to develop quantitative treatment even with portable systems. However, the interpretation of the results obtained with this technique can turn out to be problematic in the case of layered structures such as easel paintings. The use of differential X-ray attenuation enables modelling of the various layers: indeed, the absorption of X-rays through different layers will result in modification of intensity ratio between the different characteristic lines. This work focuses on the possibility to use XRF with the fundamental parameters method to reconstruct the composition and thickness of the layers. This method was tested on several multilayers standards and gives a maximum error of 15% for thicknesses and errors of 10% for concentrations. On a painting test sample that was rather inhomogeneous, the XRF analysis provides an average value. This method was applied in situ to estimate the thickness of the layers a painting from Marco d’Oggiono, pupil of Leonardo da Vinci.     

Determination of aluminium and silicon in zeolites by PIXE

Using 1.0 MeV protons on thick targets of zeolite pellets, aluminium and silicon were determined by PIXE. Results were compared with XRF data. The relative root mean square error was 3.7% and the results of the two methods agreed with a correlation factor of 0.991. PIXE analysis can be carried out on very small samples, while sample preparation involves minimal handling.     

Soft X-ray spectromicroscopy studies of pitting corrosion of reinforcing steel bar

Pitting corrosion of reinforcing steel bar (rebar) imbedded in concrete by chloride ions can cause concrete degradation. It is thus necessary to develop methods to mitigate concrete corrosion which could include using a protective polymer rebar coating. Corrosion studies of polyvinyl butyral-carbon black polymer-coated rebar using soft X-ray fluorescence (XRF) microprobe and micro-X-ray absorption near edge spectroscopy (μ-XANES) are reported in this study. After removal of the polyvinyl butyral-carbon black polymer coating, Fe Lα₁, Mn Lα₁, and O Kα₁ XRF maps were collected as well as Fe and Mn L₃-edge μ-XANES spectra from different regions across the whole rebar surface by collection of total electron yield (TEY) and partial XRF yield (PFY) spectra. The distribution of metallic Fe and Fe corrosion products was determined by analysis of the Fe XRF map. The μ-XANES spectra indicated a higher fraction of Fe (III) phases on the corroded rebar surface, while Fe (II/III) phases were the major corrosion products beneath the surface region. In addition, Mn (II) and Mn (III) were determined as the valence states of the manganese corrosion products.