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Abrasive Applications of Diamond
Published in Mark A. Prelas, Galina Popovici, Louis K. Bigelow, Handbook of Industrial Diamonds and Diamond Films, 2018
K. Subramanian, V. R. Shanbhag
The use of diamond abrasives in cutoff operations, and other surface generation needs is the basis for a variety of precision grinding applications. Carbide tools, parts, and drill bits are ground and shaped with diamond wheels. Diamond grinding wheels are used to grind the glass used in optics, the flat glass used in furniture and automotive applications, and crystal glass having intricate designs. A variety of low and high density ceramics used in kiln furniture, magnet, capacitor, spark plug, and similar applications are ground with diamond grinding wheels. Electronic ceramics such as silicon wafers, magnetic heads, optical fibers, and sensors are machined to tight tolerances and fine surface finishes with diamond grinding wheels. The potential use of engineering, technical, or fine ceramics for a wide variety of thermal and mechanical applications will call for more extensive use of diamond grinding wheels in the future. Typical products machined with diamond abrasives are shown in Figures 6 to 10.
History of Ceramics
Published in David W. Richerson, William E. Lee, Modern Ceramic Engineering, 2018
David W. Richerson, William E. Lee
One type of kiln developed in southern China during the Song (Sung) Dynasty (ad 960–1279) was the “dragon kiln.” A dragon kiln built in the twelfth century as discovered and excavated near Longquan was ~30 m long and 2 m wide.8 Constructed of brick arches covered with a thick mound of refractory earth insulation, this kiln was built climbing a 15–20° slope. The firebox was at the bottom and the flue at the top to encourage flow of heat through the furnace. Unfired porcelain items were each placed in a kiln furniture box (with lid) made of refractory clay such that ware could be stacked and essentially positioned along the whole length of the kiln. It has been estimated that a single kiln could hold as many as 100,000 pieces for a single firing, which represented a substantial level of production.
Ceramic Fabrication Methods for Specific Shapes and Architectures
Published in Mohamed N. Rahaman, Ceramic Processing, 2017
Several factors influence the reaction kinetics and the resulting microstructure, including the Si particle size, the composition and pressure of the nitriding gas, the reaction temperature, and impurities in the Si starting powder [7]. Inadequate process control often leads to problems in optimizing the properties of RBSN and in achieving consistent strength. Because of the high porosity, the strength of RBSN (flexural strength typically in the range 200–300 MPa) is inferior to that of dense Si3N4 produced by sintering or pressure-assisted sintering. On the other hand, RBSN can be produced with a high degree of dimensional accuracy and with complex shapes, with minimal need for machining after nitridation. RBSN has a high creep resistance (due to the absence of an intergranular glass phase), good thermal shock resistance (due to its low thermal expansion coefficient), and good resistance to chemical attack by several molten metals. RBSN is used in low-stress applications such as kiln furniture, but it can also be used for more sophisticated components.
The correlation between structure, multifunctional properties and application of PVD MAX phase coatings. Part III. Multifunctional applications
Published in Surface Engineering, 2020
Bulk MAX phases have been formed by a process of hot pressing of elemental powders and by the sintering of a mixture of elements or compounds under isostatic pressure at high temperatures [15,116–119,141,142,158–163], by a solid–liquid reaction synthesis [123], by a mechanically induced self-propagation reaction [164] and by spark plasma sintering [11,124]. The properties of MAX phase compounds and their potential applications are reviewed in numerous papers, for example, by Barsoum [5], Sun [11], Sun et al. [1] and Wang et al. [2] and included such application as substitution for machinable ceramics, for electrodes, exhaust gas filters for automobiles, free-cutting elements, microelectronics, bio application, damping materials (high stiffness and up to high temperatures), low friction applications based on basal plane lubricity and corrosion-resistant materials, surface coatings, defence applications, such as armour, nuclear applications, low dimensional materials, and substrates for CVD diamond, kiln furniture, heat exchangers. Furthermore, Smialek [149,151] performed the first jet-fueled burning ring test evaluating a Ti2AlC type MAX phase for turbine application to demonstrate durability in high pressure, high-velocity water vapour, i.e. environmental resistance of bulk MAX phase ceramic.
Microstructure and mechanical properties of porous SiC ceramics by carbothermal reduction and subsequent recrystallization sintering
Published in Journal of Asian Ceramic Societies, 2020
Jian-Fei Zhang, Xiao-Nan Zhou, Qiang Zhi, Shan Zhao, Xin Huang, Nan-Long Zhang, Bo Wang, Jian-Feng Yang, Kozo Ishizaki
Porous silicon carbide (SiC) ceramics are hence an ideal candidate for filters, catalytic supports, separation membranes, acoustic and thermal insulators, high-temperature structural materials, kiln furniture, thermoelectric energy conversion, and reinforcement of composites [1–5]. This is due to their unique combination of properties such as excellent mechanical properties, good chemical resistance, high thermal conductivity, low thermal expansion coefficient, and high thermal shock resistance.
Processing of electric ceramic insulators from slate rocks and MgO
Published in Materials and Manufacturing Processes, 2020
S. M. Naga, M. Sayed, M. M. El-Omla, Ahmed R. Wassel, N. El-Mehalawy
Cordierite (Mg2Al4Si5O18) is considered a promising structural material that is used in several applications due to its specific unique characteristics. It is used in kiln furniture as a thermal coat for metals for gas turbine engines in the manufacture of gas exchangers for automobile mufflers because of its low thermal expansion coefficient, premium resistance to thermal shock and high refractoriness and for solar thermal storage.[1–3] In addition, cordierite possesses a low dielectric constant with an adequate electrical resistivity, which makes it a candidate for use as an integrated circuit substrate[4–6] and in millimeter wave dielectrics.[7] Moreover, the combination of the electrical, electromechanical and thermal properties of cordierite enable it to be used in internal combustion components[8] and for thermal insulation purposes.[9] Freer and Owate (1990)[10] found that the breakdown strength for cordierite glass ceramics (SiO2–MgO–Al2O3–TiO2) is highly affected by homogeneity and crystal size and shape. On the other hand, the dielectric constant and dielectric loss of dense cordierite are reduced upon increasing both the densification temperature and the test frequency.[11] The main factors that control the development of the cordierite phase are the starting material type, composition and purity and the fabrication methods. Several attempts have been made to develop cordierite as the main phase from natural resources. Cordierite has been conventionally synthesized from natural raw materials such as magnesite, talc and kaolin.[12,13] Talc, calcined bauxite and quartz were used to prepare cordierite via solid-state reaction at temperatures ranging from 1300 °C to 1420 °C.[14] Talc carbonate rocks, kaolin, and alumina have also been used to prepare cordierite bodies.[15] The addition of 2.5 mass% B2O3 to a cordierite batch prohibited the formation of µ-cordierite and lessened the probability of any silicate phase formation except α-cordierite.[15] Piresde et al.[16] showed that the factors that affect cordierite formation are the firing temperature and the median particle size. They claimed that cordierite begins to crystallize at 1250°C, while the produced bodies are sintered at 1350°C. They also stated that batches composed of kaolin waste, MgO, and talc are suitable for the synthesis of cordierite.