摘要
由于全世界对环境保护和可持续发展的关注,陶瓷釉料的无铅化研究成为陶瓷科学与技术领域的一个重要议题。利用景德镇地区的传统陶瓷原料,采用Cu^(2+)着色,成功实现吉州窑绿釉无铅化制备,研究了铜釉色彩对烧结温度的敏感特性。结果表明:随着烧结温度升高,釉层黏度逐渐降低,釉面依次呈现青蓝、淡绿、绿色,在1280℃时达到釉面最佳效果。釉面主要以Cu^(2+)的绿色呈色为主,随着烧结温度的提高,Cu^(+)/Cu^(2+)的摩尔比逐渐增大,釉面则从蓝绿色向青绿色转变。样品均存在圆形和蠕虫状2种相分离结构,当烧结温度较高时,相分离结构收缩并进一步生长成大尺寸圆形相分离液滴,发生Mie散射产生白色乳光,加深釉面呈色。吉州窑无铅绿釉的呈色机制是由铜离子价态和相分离结构的协同耦合作用的结果。
Introduction Environmental protection and sustainable development have attracted recent attention.Especially,the lead-free reproduction of ancient ceramic glazes with rich historical and cultural values becomes a common concern for both academia and industry.Jizhou kiln is one of the well-preserved ancient kiln sites in China,and is one of the famous folk firing kilns during the Song and Yuan dynasties.Jizhou kiln green glaze is colored in addition to the chemical composition as well as coloring mechanism.The sintering temperature is also one of the key factors influencing the ceramic glaze color,microstructure,and physical properties.However,the current research on the sintering process of copper-green glaze is still insufficient.The lead-free preparation of green glaze from the Jizhou kiln was achieved using the conventional ceramic raw materials in the Jingdezhen area and Cu^(2+)coloring.The influence of sintering temperature on the formation of glaze color,microstructure,and color-presenting mechanism of lead-free green glazed ceramics,as well as the mechanism of the effect of sintering temperature on the glaze's physical properties were systematically investigated.This study provides a scientific guidance and a technical support for the lead-free reproduction of green-glazed porcelain of Jizhou kiln to further promote the protection and inheritance of traditional ceramic culture,and to provide an important reference basis for the sintering behavior of other types of glazes.Methods A base glaze was prepared using 23%(in mass fraction,hereinafter the same)wollastonite,9%talc,20%feldspar,26%quartz,10%kaolin,8%smelter's ash,and 4%zinc oxide(ZnO)from mineral raw materials originating in the Jingdezhen area of Jiangxi Province,China,with 4%CuO as a coloring agent.ZnO(99%analytically pure),CuO(99%analytically pure),and glazes were applied to blanks by an impregnation method(blanks were already 900℃plain firing),and the impregnation time was 20 s.Subsequently,the samples were put into a box-type resistance furnace and sintered in air.Six lead-free green glaze samples sintered at different temperatures(i.e.,1250,1260,1270,1280,1290℃and 1300℃)were obtained.The chemical composition of the mineral raw materials was analyzed by energy-dispersive X-ray fluorescence spectrometry.The phase structure of the sample glazes was analyzed by X-ray diffraction and micro-confocal laser Raman spectrometry.The optical photography of the sample surfaces was carried out using a super depth of field microscope.Scanning electron microscopy was used to observe the microstructure of the samples after etching with 5%HF solution for 20s as well as the fractional phase structure in the glaze.The chromaticity values and reflectance spectra of the glazes were determined by benchtop spectrophotometry as well as a UV-Vis-IR reflectance spectrophotometry.The elemental valence states were analyzed by X-ray photoelectron spectroscopy.Results and discussion The optical analysis indicates that the glaze surface changes from greenish blue to light green and green with the increase of sintering temperature,and reaches the optimum effect of glaze surface at 1280℃,at which time the glaze surface of the samples is smooth and uniformly colored,with a strong sense of glassy feeling.The results of XRD patterns and Raman spectra show that the glaze layer is composed of a glassy phase and trace SiO_(2)crystals,and the phase of glaze layer is not a main factor of color presentation.The structural analysis shows that the glaze layer is not a homogeneous material,it is composed of two kinds of phase separation structures,i.e.,round and worm-like.The phase separation structure shrinks and grows further to form a large-size round phase separation droplet,and the incident light undergoes Mie scattering with the increase of sintering temperature and the gradual decrease of high-temperature viscosity of the glaze layer,which produces a white opalescence and deepens the glaze surface coloration.Lead-free green glaze is mainly due to the effect of Cu^(2+)color presentation.As the sintering temperature increases,the Cu^(2+)concentration gradually increases,and copper ions and six bridging oxygen(O~b)form a six-coordinated structure,mainly presented in green.The coloration of lead-free green glaze is a result of the synergistic coupling of the phase separation structure and the valence state of copper ions,and the lead-free green glaze with a stable coloration and a good glaze quality can be prepared via optimizing the sintering temperature.Conclusions The viscosity of the glaze layer gradually decreased,and the glaze surface showed greenish blue,light green,and green in turn,and the optimum effect of the glaze surface reached at 1280℃as the sintering temperature increased.The glaze was mainly dominated by the green coloration of Cu^(2+),and the molar ratio of Cu^(+)/Cu^(2+)gradually increased,while the glaze changed from blue-green to lime green as the sintering temperature increased The round and worm-like phase-separated structures both appeared in the samples,and the phase-separated structures contracted at higher sintering temperatures and grew further into large-sized round phase-separated droplets,with Mie scattering occurring to produce a white opalescence that deepened the glaze coloration;The color-presentation mechanism of the lead-free green glaze was a result of the synergistic coupling of copper ion valence and phase-separated structures.
作者
温梦涛
张效华
张佩
岳振星
WEN Mengtao;ZHANG Xiaohua;ZHANG Pei;YUE Zhenxing(School of Materials Science and Engineering,Shaanxi University of Science&Technology,Xi'an 710021,China;State Key Laboratory of New Ceramics and Fine Processing,School of Materials Science and Engineering,Tsinghua University,Beijing 100084,China)
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2024年第12期3824-3831,共8页
Journal of The Chinese Ceramic Society
基金
国家自然科学基金(52273315)
陕西省教育厅科技项目(21JT003)
新疆建设兵团项目(2023AB013-04)
清华大学新型陶瓷与精细工艺国家重点实验室开放课题(KF202212)
陕西省重点研发计划(2024GX-YBXM-324)。
关键词
无铅绿釉
烧结温度
相分离结构
铜离子
呈色机制
lead-free green glaze
sintering temperature
phase-separated structures
copper ions
coloration mechanism
