基于羟基磷灰石材料的风化脆弱骨质文物加固保护研究

Consolidation of Fragile Weathered Bone Relics Using Hydroxyapatite Material as Consolidant

考古发掘出土的风化骨质文物通常疏松多孔、力学强度低、质地脆弱,易出现翘曲、开裂、酥粉化等现象,亟需探索脆弱骨质文物加固保护的新方法。本研究采用羟基磷灰石前驱材料氧化钙–磷酸氢钙的醇分散液渗入脆弱骨质内部,再用蒸馏水渗入引发氧化钙与磷酸氢钙反应而生成羟基磷灰石连续相。该连续相能填充脆弱骨内部的孔隙和裂缝,并通过桥连黏接而加固骨质。利用电镜、能谱、XRD、色差、质量、孔隙率、密度和断面强度等研究考察了悬浮分散液中氧化钙与磷酸氢钙的质量配比(1:1、1:3、1:4、1:5、1:6、1:7)和施加方式(刷涂、滴渗和浸泡)对加固效果的影响,结果表明,悬浮分散液中氧化钙和磷酸氢钙的质量配比为1:3,且施加方式为刷涂时,加固处理效果最佳。经加固处理后,脆弱骨的孔隙率下降了17.3%,质量、密度和表面强度分别提高了38.39%、34.49%和16.32%,且其色差ΔE也小于3.0,符合文物保护要求。本研究为脆弱骨质文物的加固保护提供了新的有效方法。

Archaeological weathered bones are usually porous and fragile,easily to warp,crack and crumble.To avoid these relic damages,consolidation technology is badly needed.Here,we explored a new consolidation method for weak bone relics using hydroxyapatite as protectant.Briefly,dispersion of calcium oxide mixed with calcium hydrophosphate in alcohol was used firstly to permeate into the fragile bones as precursor of hydroxyapatite consolidant.Then pure water was used to trigger the reaction between calcium oxide and calcium hydrophosphate,which leads to formation of a continuous phase of hydroxyapatite consolidant.By filling and bridging the pores or fissure inside the fragile bones,hydroxyapatite consolidant can act as a reinforcement material.Effects of the mass ratio of calcium oxide to calcium hydrophosphate(1:1,1:3,1:4,1:5,1:6,1:7)and the application ways(brushing,drip infiltration and soaking)on the protective performance were investigated by scanning electron microscope(SEM),energy dispersive spectroscope(EDS),X-ray diffraction(XRD)and characterizations of color difference,weight increment,porosity,density and cohesive strength determination.The results showed that the best consolidation performance could be obtained when the mass ratio of 1:3 and the brushing consolidation method were adopted.In this case,porosity of the fragile bones decreased by 17.3%.Mass,density and cohesive strength of the fragile bones increased by 38.39%,34.49%and 16.32%,respectively.Moreover,the color difference of bones is less than 3.0,which is allowable in the field of heritage conservation.