摘要
一水草酸钙(CaC_(2)O_(4)·H_(2)O)作为一种石质文物防风化材料,因溶度积低、与碳酸盐岩相容性好、可去除的特点受到了大量关注.在碳酸盐岩表面通过化学溶液制备防护涂层时,由于基底非均质、反应过程难控制、产物多样化的原因,易于形成有缺陷的CaC_(2)O_(4)·H_(2)O涂层,导致防护效果下降.目前主要有两种改进方法:第一种是使用酸性溶剂对CaC_(2)O_(4)·H_(2)O晶体形貌进行调整,提升致密化程度;第二种是利用草酸酯类溶液缓慢水解的特性,有效提升CaC_(2)O_(4)·H_(2)O的覆盖面积.基于此,本研究在大理石基底上依次施加了草酸铵、草酸二甲酯和乙酸钙混合溶液制备CaC_(2)O_(4)·H_(2)O涂层,且经XRD、SEM测试表明该方法制备的涂层致密化程度高,结合耐污性实验证明该涂层对于黑色结壳的形成能够起到有效抑制作用,此外可逆性实验结果表明CaC_(2)O_(4)·H_(2)O涂层易于去除,去除后不会对文物外观造成太大影响.
Calcium oxalate film or coating is well known in the field of cultural conservation as an effective method of protecting carbonate stone relics because of its low solubility,good compatibility with carbonate surfaces and good reversibility.Because of non-uniformity in the substrates,the uncontrollability of the reaction process and the amount of products that are involved when using a chemical solution method to make protective coatings on carbonate rocks,calcium oxalate coatings produced by this method are often defective and fail to protect the surfaces they cover.There are two main ways to improve the properties of these coatings:the calcium oxalate crystal structure can be modified with acidic solvents to improve coating densification,or;the area covered by the film can be increased by using slowly hydrolyzed oxalate solutions.This study sequentially applied ammonium oxalate solution,dimethyl oxalate mixed solution,and calcium acetate mixed solution to a marble substrate and then tested the surface with XRD,SEM,and stain resistance tests.The results demonstrate that the calcium oxalate coating made using these methods is denser and more effective at resisting dirt and scuffing.Moreover,the calcium oxalate coating can be easily removed with little effect on the object's appearance.
作者
查剑锐
魏书亚
马清林
ZHA Jianrui;WEI Shuya;MA Qinglin(Institute of Cultural Heritage and History of Science&Technology,University of Science and Technology,Beijing 100083,China;International Joint Research Laboratory of Environmental and Social Archaeology,Shandong University,Qingdao 266237,China)
出处
《石窟与土遗址保护研究》
2022年第3期89-98,共10页
Research On The Conservation Of Cave Temples And Earthen Sites
基金
北京市文物局项目(PXM2020-039208-000005)
关键词
碳酸盐岩
石质文物
一水草酸钙
防风化材料
多步法
carbonate rocks
stone relis
calcium oxalate
weathering resistant material
multi-step method
