Chemical hardening of glazed porcelain tiles

Abstract

Glazed ceramic tiles are used for wall and floor covering thanks to their high resistance to chemicals attacks, although big efforts should be done to increase their surfaces resistance to mechanical stresses. This study investigates the applicability of a well-known glass hardening process to glazed ceramic tiles following a rational design based on Design of Experiments technique. A Mixture Design has been carried out to formulate new frits compositions to enhance the ion-exchange process, starting from a commercial product. Vickers Hardness and SEM-EDS techniques have been employed to evaluate the frits and elaborate the model. Results suggest that frits for ceramic tiles are positively affected by ion-exchange process only if an appropriate combination of ions in the starting composition is present, establishing a new category of frit formulations suitable for that purpose. The results have been confirmed employing the optimized frit for the glazing of porcelain stoneware.

Development and Prospects of High Strength Pre-stressed Ceramics

“…1 Microstructures of A (a), M (b) and N (c) compacts, and mechanical properties of SiC compacts (d) [25] 表 1 不同体积分数纤维对 SiC 陶瓷机械性能的影响 [36] Table 1 Mechanical properties of composites with different fiber contents [36] Content of fiber 28vol% 32vol% 43vol% 55vol% Density /(g•cm - [37] Fig. 2 SEM photomicrographs of different compositions (a-d) and formation process of the mullite whisker network (e) [37] (a) [38] 。研究发现, 预应力混凝土结构的 抗裂性、刚度和承载力大大超过了钢筋混凝土结构, 不仅节约钢材, 改善结构功能, 解决了其他结构材 料难以解决的问题, 如增大房屋结构跨度、降低自 重等, 而且更是一种先进的结构形式 [39] (图 3(a))。另 一个成 功地 应用预 应力 增强技 术的 是钢化 玻璃, 1874 年由法国人发明, 采用急冷的方法制备钢化玻 璃, 并在英国申请了专利。钢化玻璃是通过在普通玻 璃表面形成一层预压应力, 能够提高玻璃的强度 2~5 倍, 并提高其热稳定性和安全性能, 并于 20 世纪初 开始在全世界范围内得到全面的推广与普及 [7,8,[40][41][42] (图 3(b))。无论是在混凝土领域还是玻璃领域, 均采 用了一种宏观结构的预应力增强设计, 预先在材料 或构件中引入压应力以便抵消外加的拉应力, 从而 增加基体受张力而开裂的应变量, 达到提高材料断 裂强度、可靠性及耐久性的目的。如木桶, 在还没装 水之前采用铁箍套紧桶壁, 便对木桶壁产生一个环向 的压应力, 若该压应力超过水的内压引起的拉应力, 木桶就不会开裂、漏水 [38] (图 3(c))。此外, 利用熔融 金属包裹陶瓷复合形成高度紧凑约束的六面压缩应 力的预应力陶瓷, 外表看似金属, 能显著提高陶瓷 抗冲击及穿透能力, 可应用于防弹陶瓷领域 [43] 。 目前, 常见的人为预加应力的方法有: 1)热韧 化处理即通过一定的加热、冷却制度在表面人为地 引入残余压应力。这种技术已被广泛应用于预应力 玻璃(钢化玻璃)行业 [7][8] 和牙科陶瓷材料行业 [44] 。 2)化学强化, 如离子置换法, 在基体升温时, 将材 料中小离子替换成大离子, 当材料冷却后, 则大离 子受到挤压形成钉扎效应, 给材料提供表层预压 力 [11][12]41,[45][46]…”

“…传统陶瓷行业的节能、减排提供新思路, 并推动建 筑陶瓷行业的技术进步, 进一步巩固我国陶瓷领域 的技术优势, 促进陶瓷行业的可持续发展、生态文 明建设及生态环境保护。但是, 高强度脆性材料通 常对表面损伤敏感, 其裂纹扩展阻力较低。 因此, 如 何在提升陶瓷材料强度的同时提升损伤容限是陶瓷 可持续发展的核心问题。 一百多年前西方学者发明了预应力混凝土和预 应力玻璃(钢化玻璃), 大幅度提高了材料的抗折强 度, 并得到了广泛应用, 从而使陶瓷材料的预应力 增强设计成为研究热点。近百年来不断有学者通过 模拟预应力混凝土 [6] 和钢化玻璃 [7][8] 的形式来制备 预应力陶瓷。但是模拟混凝土在陶瓷里面埋钢筋显 然无法高温烧结 [6] , 只适用于低温陶土。 而采用物理 钢化玻璃的方式制备预应力陶瓷, 使陶瓷处于高温 软化态后快速降温, 虽然可以提高强度 [9][10] , 但是 二次高温并使陶瓷达到熔融态, 耗能耗时难以实用 化, 同时还带来热震损伤。 此外, 模拟化学钢化玻璃 的方法对于表面含有玻璃相的陶瓷有一定的增强效 果 [11][12] , 但在经济和品种上受到限制。因此, 目前在 预应力陶瓷尝试性的研究中, 存在系统的理论研究 不足、缺乏数学几何表达和设计模型等问题, 本文总 结了当前增强陶瓷的国内外研究进展, 提出了全新的 高强度高损伤容限复合陶瓷的预应力设计及模型, 并 展望了预应力陶瓷未来的研究方向和应用前景。…”

Numerical and experimental study of ion exchange in porcelain tiles

“…On the other hand, the ion exchange process was also studied to increase some mechanical properties of ceramic glazes, such as Vickers hardness, scratch resistance, and wear resistance. Using an optimized formulation of ceramic frit, increments of up to 40% in Vickers hardness, 150% in scratch resistance, and 130% in wear resistance after application of the cation exchange process were obtained 11 …”

“…Using an optimized formulation of ceramic frit, increments of up to 40% in Vickers hardness, 150% in scratch resistance, and 130% in wear resistance after application of the cation exchange process were obtained. 11 With the aim to apply the concepts of chemical tempering to a larger manufacturing scale, this work investigates the influence of ion exchange on industrially produced porcelain tiles. On the other hand, to better understand the chemical tempering process in the microstructure of porcelain tiles, a numerical simulation of the diffusion process of potassium ions (K + ) was carried out and compared with the experimental results.…”

Preparation and strengthening mechanism of prestressed ceramic tile components

“…[22][23][24] However, strengthening ceramics by prestressing process has not been quite successful. Recent studies show that the quenching 25 or ion exchange process, [26][27] which has been used to produce…”