Orientation Patterns Characteristic for the Structure of the Ceramic Body of Wheel-thrown Pottery

The described analysis follows recent findings related to the orientation of particles and voids in a ceramic body that is characteristic for wheel-made pottery. The analysis is focused on the potential variability within wheel-throwing method and is based on an experimental collection that combines the factors of the experience and motor habits of individual potters and the vessel shape. The orientation of the components of a ceramic body is calculated for two sections: radial and tangential. The sections are analysed using optical microscopy. The calculated orientation and alignment reflect the throwing style of potters using the same forming method.

Production Technology of Glazed Pottery in Chalcis, Euboea, during the Middle Byzantine Period

This paper focuses on various categories of glazed pottery, which were in circulation in western Euboea (Greece) during the Middle Byzantine and Late Byzantine Periods. The production technology and particularly the surface treatment of Byzantine glazed pottery have been investigated on the basis of 56 ceramic fragments from a rescue excavation in Orionos street in Chalkis, Euboea. This paper focuses on the manufacture of glazed pottery within the local pottery repertoire of Chalkis, while trying to contextualise the pottery typology and to consider the issues of technology. The chemical analysis by non-invasive energy dispersive X-ray fluorescence (XRF) and Scanning electron microscopy (SEM-EDS) provided information about the compositional variation of the examined glazed ceramics assemblage. Moreover, sections of the samples were examined by optical microscopy and scanning electron microscopy (SEM) in order to determine the microstructure of the samples, as well as the vitrification and the porosity of the ceramic body. Finally, X-ray diffraction (XRD) was applied for qualitative mineralogical analysis indicating presence or absence of high temperature phases and information about firing conditions.

Toughening of Ceramic Shell Mould with Rice Husk Fiber (CSm-RH) to Improve Strength Property and Mould Performance

For ages, ceramic shell mould (CSm) have been extensively applied in investment casting industry. The formation of CSm requires multiple steps of dipping, layering drying and firing stages. The later steps are very crucial as the solidification thin layer CSm that consist of loose ceramic particles easily cracks when exposed to the higher thermal effect. The inclusion of fiber or any reinforces phases is able to enhance fired ceramic body and also strengthen the green ceramic structure. Thus, the feasibility of rougher NaOH treated rice husk fiber (RHT) prior embedded into composited structure has shown a significant CSm improvement by induced a better adhesion properties and larger bonding area with brittle ceramic matrix, resulted in increased green strength (1.34 MPa) and fired body strength (4.32 MPa). Owing to the decomposed of lignin layer in CSm with untreated rice husk fiber (CSm-RHU) exhibited a higher porosity that provide a better permeation paths of air flow during molten metal pouring as increased 30 % from the standard CSm permeability, giving an enormous benefit for investment casting cooling process. Overall, the incorporation of RHT fiber in a CSm matrix of both green and fired body governed in toughening of brittle ceramic body, hence avoid failure to the casting mould.

Heating Rate Effect during Sintering on the Technological Properties of Brazilian Red Ceramics

Unbalanced energy consumption in the production of ceramic artifacts is responsible for considerable undesirable impacts, such as increased emissions of polluting gases, excessive consumption of fuel materials, land degradation and unpredictable financial costs. By contrast, the practice of optimizing the ceramic sintering, which in associated with firing of high temperature, can result in increased productivity and reduced production costs preserving an environmentally friendly production system. Moreover, it allows further improvements in the quality of the final product. This work compares the effect of different sintering cycles, with heating rates of 2, 15 and 30°C/min, on the technological properties of a Brazilian industrial clay ceramic body. Initially the clay ceramic specimens was characterized in terms of mineralogical, chemical and physical properties. Specimens were prepared by extrusion and fired at temperatures of 800, 900 and 1000°C. The evaluated properties by standard tests were water absorption, post-firing linear shrinkage and flexural strength. It was found that owing to sintering carried out at higher heating rates, red ceramic products with superior technological properties were obtained. This is an unprecedented conclusion for common clay ceramics produced in Brazil. Based on the promising obtained results it is evidenced, in a clear and detailed way, the benefits of rapid sintering cycle application for conventional brick production.

Illuminating the Imperceptible, Researching Mina’i Ceramics with Digital Imaging Techniques

Mina’i ceramics dating to the late 12th and early 13th century made in the Kashan region of Iran represent a novel period of overglaze enamelling technology in ceramic history. New colours were used to produce stylistically attractive and dynamic polychrome motifs. Due to their archaeological context, and popularity in the art market since the mid-20th century, these objects often have complex conditions involving reconstruction and overpainting. The aesthetic and technological significance of these pieces warrants further study, but in practice, removing restorations can lead to structural destabilisation, requiring time-consuming and potentially unplanned for conservation treatment. To determine if it is possible to gain useful information from the study of these artworks without disturbing existing restorations, a group of objects were drawn from the Sarikhani and Ashmolean Museum of Art and Archaeology collections. The objective of this project was twofold, first to assess the merits of the imaging techniques for understanding condition, and second to propose a protocol for imaging with the aim of encouraging collaborative projects with international partners. The techniques used in this study include digital photography under visible and ultraviolet light, infrared reflectography, and radiography. The results show that important information invisible to the naked eye can be obtained about the decorative surfaces, using ultraviolet light and infrared reflectography. Digital radiography proved to be equally effective when studying the condition of the ceramic body. The results of this project were used to produce guidance on these techniques as a collaborative documentation package for the study of Mina’i ceramics.

Structure–Property Functions of Inorganic Chemical Binders for Refractories

For refractory application, amongst others, inorganic chemical binders are used to shape and process loose, unpacked materials. The binder influences the chemical composition within the ceramic body during setting, aging and firing and thus the finally reached properties of the refractory material. For an effective design of tailored materials with required properties, the mode of action of the binder systems should carefully be investigated. A combination of both structure analysis techniques and macroscopic property investigations proved to be a powerful tool for a detailed description of structure–property correlations. This is shown on the basis of X-ray powder diffraction and nuclear magnetic resonance spectroscopy analyses combined with observation of (thermo)mechanical and chemical investigations.

Case study of a tile facade intervention – Aveiro, Portugal

Tiles are found on numerous Portuguese facades. The exposure to external agents causes degradation and, in some cases, detachment of these tiles. In the coastal area of Aveiro city (Portugal), the building's facades, exposed to adverse atmospheric conditions are in constant contact with aggressive agents, which cause the detachment of a significant amount of facade tiles. Within the scope of the SOS Azulejo Project, and in partnership with the University of Aveiro, Fábrica Centro Ciência Viva de Aveiro, the Prison of Aveiro and DDL Arg, this study encompasses the conservation of a tile facade, after degradation and detachment of the ceramic body. Several replicas of the tiles were made in the specific context of a training action that took place at the Aveiro Prison. The technical study was carried out to analyse the compatibility and reversibility of the mortars and ceramic tiles used. The mortars were tested in their fresh and hard state for consistency through spreading, flexural tensile strength, compressive strength, water absorption, and pull-off adhesion tests on bricks surfaces. The results were satisfactory and the replicated tiles were applied on a building’s facade on the National Tile Day, as part of an awareness campaign.

Ceramics Practicum

The book presents all the methods of testing ceramic raw materials and products made from ceramic materials: first of all, the methods of testing of the properties of clay are discussed; further, determination of its chemical and mineral composition is described followed by methods for testing the key characteristics of a ceramic body and slurry, and, finally, a detailed description of methodologies for determining the performance of construction and fine ceramic products is presented. This textbook is primarily intended for English-speaking students studying the modules Chemical Technology of Ceramic Materials, Synthesis of High-Temperature Materials, Building and Fine Ceramics and Refractory and Modern Ceramics at KTU Faculty of Chemical Technology. It will also be beneficial to students of other KTU faculties or any other universities whose programs deal with the production and processing of building materials.