微晶玻璃／陶瓷复合墙地砖的研制

以接近陶瓷砖的成本生产具有微晶玻璃质量的新一代复合墙地砖是引人注目的课题。实验表明,将基础玻璃粉平铺于普通瓷质砖基板上,一起进行热处理,可制备出表层为微晶玻璃、基底为普通陶瓷的复合材料。它既具备微晶玻璃的各种优良特性和装饰效果,又可在普通陶瓷墙地砖厂通过适当技术改造来生产,具有很好的推广应用前景。     

Fabrication and properties of dense α-cordierite glass-ceramic coating on porous BN/Si2N2O ceramic

α-Cordierite glass-ceramic coating was fabricated on the porous BN/Si₂N₂O ceramic by glass-ceramic method. The effect of the heating temperature on the phase composition, microstructure, mechanical properties, water resistance and dielectric properties of the coatings was investigated. A large amount of α-cordierite precipitated from the glass phase when the heating temperature was 1050?°C and the content of α-cordierite in the coating increased with increasing the heating temperature. The resulting α-cordierite glass-ceramic coatings had a good wettability and adhesion with the porous ceramic substrate. The coating/substrate interface was continuous without defects. When the heating temperature was 1050–1200?°C, the resulting coatings possessed positive mechanical properties and good water resistance due to the high densification. And the dielectric constant and loss tangent of the coated samples prepared at 1050–1200?°C were 4.1–4.3 and 0.005–0.01 respectively in the frequency of 21–36?GHz.     

Utilization of granodiorite in the production of porcelain stoneware tiles

In the present study, the use of granodiorite, as fluxing agent in a body mix for stoneware ceramic tiles production, was assessed. Four batches were formulated using clay from Khaboba, and natural granodiorite from Saint Katherine, Sinai, Egypt. The batches were tailored to completely replace both feldspatic and inert components of stoneware ceramic tiles. Densification was studied according to ISO rules, while sinterability was estimated by optical dilatometry. The dependence of microstructure and mechanical properties of stoneware ceramic tiles on granodiorite content was discussed. Strength measurements showed that increasing granodiorite content the bending strength of the bodies increased. In particular the studied batches can be used for the production of industrial fast firing tiles. The obtained ceramic tiles possess properties similar to commercial ceramic floor and/or wall tiles.     

Acoustic and thermal performances of ceramic tiles and tiling systems

Acoustic and thermal performances of floating floor and/or radiant floor can be improved by using ceramic tiles with tailored porosity and microstructure. Porcelain stonewares are still the most widespread typology of tiles, due to their high physical and mechanical performances coming from a very low level of open porosity and water absorption (≤0.5 wt%). However their closed porosity values, usually neglected, can be significantly different from one product to another. As a consequence, the properties directly dependent on the total porosity, such as thermal and acoustic ones, may be strongly diverse among commercial tiles.Several commercial porcelain stoneware tiles having different composition, microstructure and porosity, were selected for the present work. These tiles, alone or coupled with different types of resilient underlayer materials (glass fibre, cork and rubber), were studied on the basis of dynamic stiffness. Their acoustic and thermal properties were investigated in terms of thermal conductivity and walking noise reduction.     

新型纳米防污剂对瓷质抛光砖的表面修复

论述了瓷质抛光砖表面被新型纳米防污剂处理前后的显微结构,新型纳米防污剂的表面修复作用和防污机理。纳米防污剂有效填充了抛光砖表面的开口气孔,显著提高了抛光砖的防污特性。经新型纳米防污剂处理的抛光砖具有优异、持久的防污性能。     

复合型陶瓷薄板的制备及其力学性能

作为一种轻薄、低能耗的功能化产品,陶瓷薄板因强度低而应用受限,如何对其进行低成本增强成为工业领域研究热点。本文以构筑“纤维布-黏结剂-陶瓷薄板”多层复合结构作为切入点,将多种工业级纤维布、黏结剂和陶瓷薄板进行二次后加工复合,制备了兼具低成本和优异力学性能的复合型陶瓷薄板,探究了其断裂面微观形貌及断裂机理。经研究表明,“碳纤维布-环氧树脂-陶瓷薄板”复合型陶瓷薄板具有最佳界面结合强度及力学性能,其抗弯强度和承载冲击能量分别为85.26 MPa和1.45 J,与陶瓷薄板坯体相比,性能提升幅度分别高达22.98%和141.67%。“纤维布-黏结剂-陶瓷薄板”多层复合结构能够有效提升陶瓷薄板综合力学性能,陶瓷薄板内部存在微裂纹拓展、纤维偏转等多种良性强韧化机制。     

Microstructural and mechanical changes by chemical ageing of glazed ceramic surfaces

In the present work, several ceramic tiles, characterised by different glazes, were considered in order to define the role played by the glassy and crystalline phases on the leaching mechanisms and the deterioration of the mechanical properties. The glazed working surfaces were subjected to chemical attack by using a strong basic solution and the chemical analysis of the leached solutions was performed. Before and after the chemical attack, the glazed surfaces of the samples were analysed from both the microstructural and mechanical point of view. In this context, the microstructure was observed by SEM and analysed by X-ray diffraction. In order to define other possible changes, roughness measurements, Vickers hardness and micro-scratch tests were also performed.The results made it possible to deepen the understanding of the mechanisms of elements release caused by the chemical attack and their implications on microstructural and mechanical degradation of the working surface of glazed ceramic tiles.     

微晶玻璃釉的研究

用不同组成的微晶玻璃水淬料,施于陶瓷坯上经核化、晶化,同时完成烧成,而获得微晶玻璃釉层.其工艺制度可以结合DTA分析,通过实验来确定.微晶玻璃釉要和坯料相匹配:釉和坯的膨胀系数相近,微晶玻璃的晶化温度和坯的烧成温度要相一致.     

Alterations in cordierite based burners subjected to radiant mode ageing conditions

Industrially developed perforated cordierite ceramic tiles were aged under accelerated conditions in a radiant combustion mode. Changes in the original phases, microstructure and mechanical properties were evidenced in the aged plates. The extent of the degraded zone was localized at the uppermost layer of the burner. These effects are attributed to corrosion of the cordierite-based material by gaseous species generated in the combustion.     

Functionalization of ceramic tile surface by soluble salts addition: Part I

The aim of this investigation was the surface functionalization of industrial ceramic tiles by soluble salts addition to improve mechanical properties (resistance to scratch and wear) preserving the aesthetical aspect of the final product. This objective was pursued through the application of different solution of zirconium capable to be transformed in zirconia nanoparticles during the material sintering. The solutions, in different concentrations, were deposited (300 g/m²) on unglazed green tiles by air-brushing. The obtained products were polished and characterized in terms of microstructure, surface micromechanical and technological properties based on the UNI EN ISO reference rules. The final aesthetical aspect of the products and the obtained hue variation were evaluated by means of UV–vis spectroscopy and colorimetric analysis.     

Microstructure design and preparation of Al2O3/TiC/TiN micro-nano-composite ceramic tool materials based on properties prediction with finite element method

The objective of this paper was to improve the accuracy of semi-empirical method used to design ceramic cutting tool materials. The mechanical properties were predicted by employing finite element model of material microstructure, so as to design microstructure and prepare new ceramic materials. Based on the Voronoi and randomness method, the microstructure model representing the complexity and randomness of micro-nano-composite ceramic material microstructure was established. Combining the representative volume element (RVE) of ceramic material microstructure with mechanical tests, the simulations of mechanical tests were conducted to acquire the flexure strength, fracture toughness and hardness of materials. The microstructure models with various parameters were designed and the material properties were predicted to determine the optimal microstructure parameters. Then, The ceramic cutting tool materials possessing the optimal microstructure parameters were developed for machining ultra-high strength steels. The results showed that the mechanical properties of ceramic materials first improved and then declined as the nano-scale TiC volume fraction increased. To obtain the best comprehensive mechanical properties, the contents of micro-scale TiN, TiC and nano-scale TiC were set as 20%, 10% and 10%, respectively. The prepared ceramic materials possessed the flexure strength of 881.4 MPa, the fracture toughness of 7.8 MPa m^1/2, and the Vickers hardness of 20.8 GPa. This research is beneficial to the development of cutting tool design theory and the improvement of the tool life.     

Direct ink writing of aluminium oxynitride (AlON) transparent ceramics from water-based slurries

In this study, transparent AlON ceramics were fabricated via the direct ink writing (DIW) method from the water-based ceramic slurry. The solids loading of the ceramic slurry was optimised by changing the dispersant content, and the printability and water content were then adjusted by adding hydroxyethyl cellulose (HEC). The structure of the green body was complete and no impurity phases were detected. The effects of sintering temperature and dwell time on the bulk density, phase evolution, microstructure, in-line transmittance, and mechanical properties of the ceramics were studied systematically. High optical and mechanical properties of 10 × 10 × 0.9 mm³ single-phase AlON ceramic tiles were obtained by sintering at 1960 °C for 10 h in a nitrogen atmosphere: in-line transmittance of 81.90% at a wavelength of 780 nm, fracture toughness of 1.74 MPa·m^1/2 (2.94 N), and Vickers hardness of 18.56 GPa (2.94 N). This study provides a novel method for synthesising AlON transparent ceramics from water-based ceramic slurries.     

Granite as flux in stoneware tile manufacturing

Natural granite was used to completely replace both feldspathic and inert components of a traditional ceramic body. Raw material from Sinai (Egypt) was added (in the range 20-35 wt%) to a commercial Egyptian ball clays (from Aswan, Egypt) in order to obtain laboratory tiles sintered at 1220 °C.Densification was studied according to ISO rules, while sinterability was estimated by optical dilatometry. Chemical, physical and microstructural analyses were accomplished to find the relationship between both the phase composition and microstructure of the fired bodies properties. The fired samples show moderate thermal expansion as well as reasonable bending strength. Therefore, as a nonconventional raw material in the modern ceramic production, the studied batches are recommended for the production of industrial fast firing tiles showing properties similar to commercial ceramic floor and/or wall tiles.     

Anorthite-based transparent glass-ceramic glaze for ceramic tiles: Preparation and crystallization mechanism

A series of high hardness anorthite-based transparent glass-ceramic glaze was successfully developed for ceramic tiles. These glazes were prepared by mixing a high-calcium frit (denoted as HCa) that can crystallize anorthite with other fluxes. The effect of HCa content on the crystalline phase, microstructure and properties of the glaze was studied. In addition, the phase transformation, microstructure evolution and crystallization kinetics of anorthite from frit glaze were investigated in detail. The results revealed that when the HCa content was 45–55 wt%, the glazes had excellent transparency with a hardness of 6.4–7.3 GPa, which was higher than conventional glazes. The XRD and SEM tests showed the crystallization of single-phase lamellar-shaped anorthite crystals up to 20–40 μm in length. Anorthite was found to crystallize directly from the frit glaze at 850 °C. The laminated anorthite was composed of thinner lamellae, and cracks were observed inside the large crystals. The activation energy of anorthite crystallization was about 420 kJ/mol, and the Avrami index (n) was 2.03?2.36. The n value indicates that the crystal is grown in two dimensions, which explains the formation of lamellar-shaped anorthite in SEM.     

PVD hard coatings on ceramic tiles for aesthetic applications: surface characterisation and corrosion properties

The development of innovative ceramic tiles looks for materials with improved mechanical and tribological properties as well as a higher corrosion resistance (high relative humidity, daily watering, household chemical cleaners). In addition, a greater durability leads to lower environmental impact. Along with their improved functionality and recyclability, ceramic tiles should also provide aesthetic properties. Ceramic tiles can be treated to modify the physico-chemical properties of the surface by metal coatings or metallic compounds, also providing an attractive metallic sheen appearance. In the present paper, titanium nitride (TiN) and zirconium nitride (ZrN) coatings were deposited on glazed porcelain stoneware by an industrial PVD multicathode arc deposition system under a reactive nitrogen atmosphere. After the process, the tiles showed a gold-like colour, a smooth surface and a coating thickness between 0.7 and 1.6 μm. The coating composition, scratch resistance and corrosion behaviour have been evaluated. It can be concluded that both coatings are suitable for use in domestic environments due to their stability and resistance to aggressive conditions. Few references have been found regarding these coatings on ceramic tiles for domestic and industrial applications, but it has been proved that they bring added value to traditional ceramics, giving new functional properties of ceramics both decorative and highly corrosion and mechanical resistance.     

抗菌功能陶瓷釉面砖的研究

通过在釉中引入银系无机抗菌剂,研制了低温一次快烧的具有抗菌功能的陶瓷釉面砖。采用陶瓷试验系统（ｃｅｒａｍｉｃ ｍｅｃｈａｎｉｃａｌ ｔｅｓｔ ｓｙｓｔｅｍ,ＭＴＳ）用ＳＥＭ,ＥＰＭＡ等测定了材料的理化性能及微观结构。结果表明,该材料具有良好的抗菌性、耐久性及坯釉结合性,其他技术性能均达到国标。     

水煤浆渣用于烧制陶瓷的研究

建筑陶瓷业每年要产生大量的水煤浆渣,废料堆放成为重要难题。这里以建筑陶瓷水煤浆废料为主要原料研制了以石英和莫来石为主晶相的陶瓷抛光砖,并采用XRD、SEM分析了建筑陶瓷水煤浆渣掺量对陶瓷抛光砖的晶相、气孔结构与断裂模数的影响。研究结果表明:水煤浆渣掺量为5%的抛光砖具有很好的力学性能,满足瓷质砖标准。     

Effect of porosity on the elastic properties of porcelainized stoneware tiles by a multi-layered model

Porcelainized stoneware represents a leading product in the world market of ceramic tiles, thanks to its relevant bending strength (with respect to other classes of tiles) and extremely low water absorption: these properties derive from its really low content of residual porosity. Nevertheless, an accurate investigation of the cross section of a porcelainized stoneware tile reveals a non-uniform distribution of the residual pores through the thickness, which results in a spatial gradient of properties. Porcelainized stoneware, therefore, may be looked at as a functionally graded material. In the present research, commercial porcelainized stonewares were analysed in order to define the effect of the residual porosity and its spatial distribution on the mechanical properties of tiles. Polished cross sections of porcelainized stoneware tiles were investigated by optical and scanning electron microscopy in order to define the content and distribution of residual pores as a function of distance from the working surface. For each porcelainized stoneware, the local elastic properties of the ceramic matrix were measured by a depth-sensing Vickers micro-indentation technique, then the so-obtained microstructural images and elastic properties were used to model the stoneware tile mechanical properties. In particular, the cross section of each tile was described as a multi-layered system, each layer of which was considered as a composite material formed by a ceramic matrix and residual pores. The elastic properties of each layer were predicted by applying analytical equations derived from the theory of composite materials and, as a new approach, by performing microstructure-based finite element simulations. In order to validate the proposed multi-layered model and identify the most reliable predictive technique, the numerical results were compared with experimental data obtained by a resonance-based method.     

瓷质抛光砖表面显微结构与防污性能的关系探讨

采用光学显微镜、扫描电镜等对抛光砖的表面显微结构进行了研究。结果表明：气孔率对抛光砖的防污性能有明显影响，但抛光砖中石英晶体在冷却过程中与玻璃体膨胀系数的差异产生的热应力，促使玻璃体沿石英周边形成了微裂纹，抛光时机械力的作用使晶粒剥落造成表面孔洞，是造成瓷质抛光砖容易吸污的主要原因之一。     

热处理工艺对高炉矿渣微晶玻璃性能的影响

以某高炉矿渣为主要原料,采用熔融法制备了CaO-Al_2O_3-SiO_2系矿渣微晶玻璃。研究了热处理工艺对矿渣微晶玻璃力学性能的影响,得出热处理工艺影响因素的先后顺序为:核化温度-核化时间-晶化时间-晶化温度,确定最佳热处理工艺为:770℃核化3 h,930℃晶化2 h,在此热工艺条件下制备的微晶玻璃抗弯强度最大,为153.67 MPa。利用X射线衍射(XRD)、扫描电镜(SEM)、能谱(EDS)测试方法分析了矿渣微晶玻璃的显微结构和晶体微观结构。