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Whiteware and Glazes
Published in Debasish Sarkar, Ceramic Processing, 2019
The clay–quartz–feldspar phase diagram represents the composition of all types of whiteware bodies, such as porcelain stoneware, white stoneware, soft porcelain, hard porcelain, laboratory porcelain, stoneware, earthenware, and dental porcelain. To understand batch composition, let us consider the example of dental porcelain near the feldspar region in Figure 7.1 (right), showing dental porcelain containing >75% feldspar, <10% clay minerals, and the rest quartz. In order to pick up the apposite composition for the particular whiteware, the mentioned phase diagram can be employed. In Figure 7.1, a typical hard porcelain is marked “O” and the composition is determined and guided by the dotted line. Herein, the particular position shows that the composition contains clay (48 wt.%), quartz (28 wt.%), and feldspar (24 wt.%). Owing to the conventional approach, one can pick up any mass fraction for whiteware.
Mechanical Properties
Published in Mary Anne White, Physical Properties of Materials, 2018
In many cases, mechanical properties are the most important factor in determining potential applications of a material. Stiffness, tensile strength, and elastic properties are important in material applications as seemingly diverse as sound production from piano strings to the strength of dental porcelain to the protection of a bulletproof vest. Some high-temperature superconductors have very useful electrical and magnetic properties but are limited in their applications due to their mechanical properties. The aim of this chapter is to provide a basis for consideration of mechanical properties, based on a microscopic picture that has developed from experimental observation. We begin with relevant definitions.
Chemical strengthening of zirconia/swelling mica composites by ion-exchange in molten salts
Published in Journal of Asian Ceramic Societies, 2021
Yuji Takita, Tomohiko Yamakami, Tomohiro Yamaguchi, Seiichi Taruta
As the strengthening method for glasses, chemical strengthening by ion-exchange is well known [8–11]. In this method, alkali ions in glasses are exchanged for other cations with a larger size in the molten salts, which induces the compressive stress near surface of the glasses. The compressive stress inhibits the development of cracks near surface of the glasses, resulting in the strengthening of the glasses. Recently, the chemically strengthened glasses have been used as protective covers of smartphones, etc. [11]. This strengthening method is applied to glass ceramics [12–23]. The flexural strength of nepheline glass ceramics was dramatically increased from 58 to 1300 MPa by exchanging Na+ ions in nepheline crystals for K+ ions [12,13]. Also, stuffed β-quartz glass ceramics [14], dental glass ceramics such as lithium disilicate glass ceramics [15–18] and Li2O-Al2O3-SiO2 (LAS) glass ceramics [19], leucite-reinforced dental glass [20], and dental porcelain [21–23] have been strengthened by the ion-exchange.
Evaluation of morphology, hardness and structure of laser exposed dental porcelain
Published in Radiation Effects and Defects in Solids, 2022
Abdul Rab, Khurram Siraj, Muneeb Irshad, Shazia Naz, Anwar Latif
The commercially available dental porcelain has an average hardness number of 380 VHN (5). The variation of hardness as a function of the number of laser pulses is presented in Figure 4, with linear fitting.