翡翠成分、结构和矿物组成的无损分析
文献类型：学位论文
| 作者 | 孙访策 |
| 学位类别 | 硕士 |
| 答辩日期 | 2011 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 干福熹 |
| 关键词 | 翡翠 便携式X射线荧光分析 X射线衍射 激光拉曼光谱 无损分析 |
| 其他题名 | Non-destructive analysis of chemical composition，structure and mineral constitution of jadeite jade |
| 中文摘要 | 翡翠是中国玉文化极其重要的一份子，也是享誉国内外的著名玉石。翡翠高昂的价格限制了用于研究的样品范围，而且翡翠在珠宝市场上是一种重要的玉石，目前面临着鉴定和分级的难题。因此，探索各种无损分析技术在翡翠中的应用，建立和丰富相关的数据库，具有非常重要的意义。 利用便携式能量色散型X射线荧光(portable energy-dispersive X-ray fluorescence，PXRF)、外束质子激发X射线(external beam proton induced X-ray emission，PIXE)、X射线衍射(X-ray diffraction，XRD)和激光拉曼光谱(laser Raman spectroscopy，LRS)对翡翠样品进行了成分、结构和矿物组成分析。结果表明，样品组成较为单一，主要由较纯的硬玉组成，次要元素含量较低，测试的21块样品中有2块样品含有少量绿辉石，1块样品主要组成矿物为绿辉石。利用LRS测试样品的裂隙处，发现6块样品中含有白蜡，1块样品中含有环氧树脂。无损分析技术在翡翠中的应用拓展了翡翠样品的研究范围，为翡翠的进一步研究、鉴定和分级提供了技术支持。 本文讨论了样品的尺寸和表面状况对PXRF分析结果的影响。样品尺寸和表面不平等因素均会低估特征X射线的强度，从而使元素含量偏低。工作曲线截距较大是造成归一化方法不适用的主要原因，并提出了利用拟合的经验方程校正实验结果的方法。本文还讨论了块体样品的均匀程度、形状、样品表面偏离测试平面等情况对XRD测试结果造成的影响。上述讨论为PXRF技术和XRD技术应用于各种形状和表面状况的玉石样品奠定了基础。 利用三种激发波长(488, 632, 785 nm)的激光拉曼光谱技术对翡翠样品的矿物和人工添加物进行了鉴定，并提出了测试样品中有机添加物的方法和实验条件。 在长波长光(785 nm和632.8 nm)激发下，部分翡翠样品的Raman光谱产生特征性的荧光背景。785 nm光激发下的荧光背景仅在绿色和白色翡翠中出现，且产生的荧光背景峰值和Cr含量呈正相关，这说明785 nm激发下的荧光背景可能是由Cr元素引起。这可能对绿色翡翠的致色机理研究和染绿色翡翠的鉴别均有重要的意义。 |
| 英文摘要 | Jadeite jade plays a significant role in Chinese jade culture, and is a very famous jade both at home and abroad. The high price of jadeite jade limits the range of samples for research. In addition, jadeite jade is an important jade in jewelry market, facing the challenges of identification and classification. Therefore, it is meaningful to apply and develop the non-destructive techniques on jadeite jade by establishing and enriching the relevant databases. The techniques of portable energy-dispersive X-ray fluorescence analysis (PXRF), external beam proton induced X-ray emission (PIXE), X-ray diffraction (XRD) and laser Raman spectroscopy (LRS) were employed to analyze the chemical composition，structure and mineral constitution of jadeite jade. The results indicated that most samples are constituted by almost pure jadeite with low concentration of secondary elements. Two samples contain a little omphacite and one sample is composed only by omphacite within 21 tested samples. By using the laser Raman spectroscopy for testing the fissures of the samples，wax was found in 6 samples and epoxy resin was found in one sample. The application of non-destructive techniques in jadeite jade broadens the range of samples for future study and provides technical support for jadeite jade’s further study, identification and classification. In this paper, the influences of sample’s size and surface condition on the PXRF results were discussed. The factors, such as the size and curved surface of the samples, make the characteristic X-ray intensity underestimated, leading to the underestimation of the concentration of elements. The great intercept of calibration curve is the chief cause of the fact that normalizing can not correct that underestimation. An alternative method for calibration by using the fitted empirical equations was introduced. The effects of the conditions, such as the uniformity and shape of bulk samples and the deviation of the sample’s surface from the testing plane, on the XRD results were discussed too. The discussions laid a foundation for the application of PXRF and XRD techniques on the jade samples with different shapes and surface conditions. The laser Raman spectroscopy (LRS) technology with three excitation wavelengths (488, 632, 785 nm) has been used to identify the mineral phase structure and organic compounds within the samples, followed by the discussion of the means and experimental conditions for the organic additives testing. The laser Raman spectra of some samples exhibited characteristic fluorescence background under the long excitation wavelengths (785 nm and 632.8 nm). The characteristic fluorescence background excited by 785 nm laser only appeared in the laser Raman spectra of green and white samples. And it seems that there is strong positive correlation between characteristic fluorescence background and the concentration of chromium, implying that the fluorescence background was possibly induced by Cr. This suggestion may be of importance for both the study of coloring mechanisms of green jadeite jade and the identification of the dyed samples. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16693]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 孙访策. 翡翠成分、结构和矿物组成的无损分析[D]. 中国科学院上海光学精密机械研究所. 2011. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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