传统陶瓷中结构羟基的光谱学研究

Spectrometric Investigation of Structure Hydroxyl in Traditional Ceramics

烧结粘土产品可以吸收水分子发生再羟基化,生成结构羟基的量与产品保存时间存在一定关系,基于该理论可以利用热重分析方法对陶器制品进行测年研究。红外与拉曼光谱技术也可以用来分析结构羟基信息,因此人们希望探索利用光谱分析方法代替热重法进行传统陶瓷无损测年分析。为了验证可行性,收集了多种典型矿物原料和可溯源的传统陶瓷样品,利用红外光谱和拉曼光谱分析它们内部结构羟基的情况。两种方法都可以观测到正长石、瓷土和高岭石中铝羟基在3600~3700 cm;范围内的特征峰。分析传统陶瓷样品时,红外光谱中未在这一范围内观测到结构羟基的峰位。利用拉曼光谱分析,激发光波长为532 nm时可以在多种类型陶瓷产品的光谱3600~4000 cm;范围内观测到两个明显的谱峰。改变光源波长,不能在相应区域观测到谱峰。但当光源波长为514 nm时,可在4288和4512 cm;处观测到两个谱峰。将拉曼谱图转换为波长显示模式,激发光波长为532和514 nm时观测到的谱峰都可对应在约659和669 nm处。基于分析结果,推知当激发光波长为532 nm时,在拉曼光谱中3600~4000 cm;范围内观测到的两个谱峰不是结构羟基的特征峰,而是较为尖锐的荧光峰。在目前技术条件下,拉曼和红外两种光谱学手段难以应用于我国高温陶瓷产品的再羟基化测年研究。

Fired clay products can absorb water molecules and be re-hydroxylated,and the amount of structural hydroxyl groups generated has a certain relationship with the storage time.Based on the theory of rehydroxylation in fired-clay,thermogravimetric analysis can be used to study the dating of pottery products.Infrared and Raman spectroscopy techniques can also be used to analyze the structural hydroxyl information in mineral materials,so people hope to explore the use of spectral non-destructive analysis for dating traditional ceramics instead of the thermogravimetric method.In order to verify the feasibility,we collected a variety of typical raw materials and traceable ancient ceramic potshards in this paper and analyzed their internal structural hydroxyl groups by infrared and Raman spectroscopy.The obvious peaks of aluminum hydroxyl in orthoclase,porcelain clay and kaolinite can be observed in the range of 3600~3700 cm;both in infrared and Raman spectra.When analyzing traditional ceramic samples,there is no peak of the structural hydroxyl group in this range in the infrared spectrum.When the wavelength of the excitation light of the Raman spectroscopy is 532 nm,two obvious peaks can be observed in the range of 3600~4000 cm;in the spectra of many samples.When the wavelength was changed,there was no peak in the corresponding rang.Especially when the excitation light wavelength is 514 nm,two peaks can be observed at 4288 and 4512 cm;.The peaks observed when the excitation light wavelengths are 532 and 514 nm can correspond to about 659 and 669 nm in the wavelength mode of Raman spectra.The results showed that when the excitation light wavelength is 532 nm,the two peaks observed in the range of 3600~4000 cm;in the Raman spectrum should not be characteristic signal of structural hydroxyl groups in minerals,but rather sharp fluorescence peak.Under current technical conditions,infrared and Raman spectroscopy is difficult to be applied for rehydroxylation dating of Chinese traditional high-temperature ceramic products.