高耐磨高析晶度透明微晶熔块釉的结构演变与性能调控

The weak mechanical abrasion resistance of glazed ceramic has become a key bottleneck to restrict the high-end oriented development of ceramic products and the corresponding industrial upgrading. This project will combine glass and ceramic science, being aimed to improve the abrasion resistance of ceramic glaze by utilizing a highly crystalline transparent glass-ceramic frit as ceramic glaze. It is difficult to form a large number of nuclei in a short time for the rapid firing of building ceramics, and the optical transmission rate of crystallization glaze is hard to improve. In order to solve these problems, the traditional mindset of homogeneous ingredients of frit glaze is broken and a new idea that two frit glazes with different initial melting points but similar composition and refractive index mixed together is first proposed in this project. This project will focus on the formation process of transparent amorphous interfaces in mixed frit at high temperature and the influence mechanism of the interfaces reduced the nucleation barrier. The influence mechanism of the interfacial energy and the fluctuation of the concentration near the interface on the formation of crystal nucleus will be revealed. To obtain the key technologies to preparation a ceramic frit with highly crystalline and high transmittance, the effect of thermal fluctuation of crystallization temperature perturbation during cooling process on the evolution of micro-structure and the controllable regulation principle of refractive for crystal and glass phase in mixed frits will be intensively studied. This project is expected to break through the limitations of available knowledge and application on traditional fritted glaze for building ceramic tiles, to deepen the theoretical basic of the transparent glass-ceramic frit, and to promote the wide application of the developed highly crystalline glass-ceramics as ceramic glaze products.

釉面耐磨性不足的问题已成为制约陶瓷产品高端化发展与产业转型升级的瓶颈。本项目将玻璃科学与陶瓷科学交叉融合，采用高析晶度透明微晶熔块作为陶瓷釉料以提高其耐磨性。针对建筑陶瓷快速烧成条件下晶核在短时间内难以大量形成、析晶后釉面光学透过率低等问题，突破传统熔块釉均质配料的思维定势，首次提出利用两种始熔点不同、但组成与折射率相近的混合熔块共同作为釉料的新思路。深入研究混合熔块在高温下透明非晶界面的形成过程及对降低晶核成核势垒的影响机制，揭示界面能与界面附近浓度起伏对促进晶核形成的作用机理，探讨冷却过程中晶化温度场微扰动形成的热起伏对微晶熔块结构演变的影响规律，探索微晶熔块中晶相与玻璃相折射率的双向可控调节原理，获得高析晶度高透过率微晶熔块制备关键技术，显著提高陶瓷釉面耐磨性。本项目将突破陶瓷界对传统熔块釉的认知与利用局限，深化透明微晶熔块釉制备的基础理论，促进高性能微晶釉料在陶瓷材料中的推广应用。

釉面耐磨性不足的问题已成为制约陶瓷产品高端化发展与产业转型升级的瓶颈。本项目将玻璃科学与陶瓷科学交叉融合，采用高析晶度透明微晶熔块作为陶瓷釉料以提高其耐磨性。针对建筑陶瓷快速烧成条件下釉面光学透过性差、显微硬度低等问题，突破传统熔块釉均质配料的思维定势，首次提出利用多种始熔点不同、但组成与折射率相近的混合熔块共同作为釉料的新思路。深入研究了基于MgO-Al2O3-SiO2(MAS)组成的系列玻璃的结构演变与性能调控，获得了高析晶度高透过率混合微晶熔块制备的关键技术。研究发现B2O3能有效降低MAS玻璃的熔制温度，促进高温熔体的均化与澄清，同时降低玻璃的体积密度和软化温度，但当B2O3的添加量达到24%时将导致玻璃中形成大量分相液滴而呈色，进一步增加B2O3使得分相液滴尺寸增大而导致玻璃失透。FTIR证实当B2O3添加量少于5%时，B原子主要以[BO4]形式存在，因而可以改善玻璃的网络结构。MAS体系玻璃在不添加成核剂时不具备整体析晶能力，在950 ℃表面/界面开始析出μ-堇青石晶体和β-堇青石晶体，随着晶化时间延长μ-堇青石逐渐转化为β-堇青石；当晶化温度为1000 ℃以上时，主晶相转变为α-堇青石。课题利用MAS体系中不同成分的混合熔块界面处高能量的特点，实现了混合组成熔块的快速析晶，从而获得以表面析晶方式显著增强玻璃表面硬度、同时保持玻璃优异光学性能的新技术。研究结果表明，当MAS体系玻璃中B2O3添加量为3%，在850 ℃核化60 min、1000 ℃晶化180 min时，可在玻璃表面形成一层垂直表面定向生长的堇青石晶体阵列层，该晶体层可赋予微晶玻璃高达998.1 kg/mm2的超高表面显微硬度，同时定向排列的晶体能够大幅度降低对光的衰减，使表面析晶后微晶玻璃在可见光区间的光学透过率仍然高达85%，从而获得釉料用高硬度高耐磨透明微晶熔块。本项目相关技术成果已在唐山某公司实现规模化应用，结果表明该技术可显著提高陶瓷用透明釉的显微硬度和表面耐磨性。