基于拉曼光谱成像技术的铁质文物锈蚀产物定量模型研究

Research on Quantitative Model of Corrosion Products of Iron Artefacts Based on Raman Spectroscopic Imaging

铁质文物是我国文化遗产的重要组成部分。由于化学性质较为活泼,铁质文物易发生腐蚀劣化。锈蚀产物对铁质文物的稳定性有较大影响,因此判断铁质文物锈蚀产物的组成特征,对于铁质文物稳定性评估具有重要意义。以赤铁矿(α-Fe_(2)O_(3)),磁铁矿(Fe_(3)O_(4)),四方纤铁矿(β-FeOOH)三种铁质文物的锈蚀产物为研究对象,采用拉曼光谱成像结合主成分回归法(PCR)和偏最小二乘法(PLS),同时结合多种预处理方法,构建了两组二元混合锈蚀(α-Fe_(2)O_(3)+Fe_(3)O_(4),α-Fe_(2)O_(3)+β-FeOOH)的定量模型。结果表明,对于α-Fe_(2)O_(3)+Fe_(3)O_(4)二元体系,PCR和PLS算法构建模型的定量效果基本一致,α-Fe_(2)O_(3)和Fe_(3)O_(4)的PLS定量模型结果均表明,一阶导数+Savitsky-Golay(S-G)平滑(9)条件下建模效果最好。对于α-Fe_(2)O_(3)+β-FeOOH二元体系,PLS方法所构建模型优于PCR方法,α-Fe_(2)O_(3)和β-FeOOH的PLS定量模型结果均表明,MSC+S-G平滑(5)条件下建模效果最好。研究结果为定量评估铁质文物锈蚀产物的化学稳定性提供了有效方法。

Iron artefacts are important part of the cultural heritage in China.Due to the high activity of iron,iron artefacts are prone to corrosion and deterioration.Corrosion products greatly influence the stability of iron cultural relics.Therefore,determining the composition of iron corrosion products is significant for evaluating iron artefacts’stability.In this study,pure chemical reagents were used to simulate three types of corrosion products commonly found on iron artefacts,including hematite(α-Fe_(2)O_(3)),magnetite(Fe_(3)O_(4)),and akaganeite(β-FeOOH).Raman spectroscopic imaging,combined with Principal Components Regression(PCR),Partial Least Squares(PLS)and multiple spectral pretreatment methods,were applied to establish quantitative models for two sets of a binary mixture of standard corrosion samples(α-Fe_(2)O_(3)+Fe_(3)O_(4),α-Fe_(2)O_(3)+β-FeOOH).The results indicate that,forα-Fe_(2)O_(3)+Fe_(3)O_(4)mixed standard samples,the model effects of PCR and PLS algorithms are not much different.The quantitative model results show that the best spectral processing method of PCR modeling is first derivative+Savitsky-Golay(S-G)smoothing(9).Forα-Fe_(2)O_(3)+β-FeOOH mixed standard samples,the model constructed by the PLS method is superior to the PCR method.The best PLS modelling spectral processing method is MSC+S-G smoothing(5).The research results provide an effective method for quantitatively evaluating the chemical stability of corrosion products of iron artefacts.