Chemical research needed to improve high-temperature processing of advanced ceramic materials (Technical report)

Abstract

Republication or reproduction of this report or its storage and/or dissemination by electronic means is permitted without the Chemical research needed to improve high-temperature processing of advanced ceramic materialsAbstract: Of the principal classes of engineering materials, ceramics are in many ways the most interesting and challenging. Many properties, or combination, of properties, not achievable with other classes of materials give ceramics enormous technical potential. The main obstacles that prevent the wider use of ceramics include insufficient reliability, reproducibility, and high cost. The physical basis of the processing steps is well established, however, the chemical reactions which occur during the high-temperature processing frequently influence the densification process and microstructure development of ceramics in an unpredictable way. Therefore, an ability to understand and control the chemical processes that occur during ceramic processing are necessary to advance and open up new uses for technical ceramics. The aim of this present report, resulting from discussions of an ad hoc group of ceramists and chemists, is to expose the areas of chemical research that can most benefit the processing, and further the use, of ceramic materials.

Dopant control over the crystal morphology of ceramic materials

“…This is indeed observed experimentally. 1 In all our experiments we used ca. 5 g of starting materials, corresponding to roughly 18 wt% of CaCO 3 , 8 wt% TiO 2 , 74 wt% KF and if Ni-doped we added ca.…”

“…Transition metal oxides and other ceramic materials are the key component in a range of advanced technologies, from microelectronics (for example dielectric resonators and piezoceramics) to heterogeneous catalysis [1]. These materials are easily processed as aggregates of microcrystalline particles.…”

“…When the active phase is in this physical form, the relevant materials and device properties are often controlled by the size and shape of the constituent particles as much as by their chemical composition. Developing the ability to engineer crystal morphologies with desirable properties for optimal processing and end-use, is therefore a high priority area in current materials science [1,2]. The surface behavior of a crystal is completely described by its morphology, as it characterizes the type and relative area of the surfaces exposed.…”

Decomposição ácida assistida por ultrassom para a determinação de Cu, Fe, Mg e Zn por F AAS em cerâmicas de uso doméstico

“…3 De modo geral, os processos de fabricação das cerâmicas variam de acordo com o tipo de peça ou de material desejado, os quais envolvem a preparação da matéria prima, o tratamento térmico e o acabamento final. 4 A primeira aplicação dos materiais cerâmicos ocorreu no período neolítico, em que eram fabricados de argila e cuja utilização servia para a conservação de água e de alimentos. 5,6 Dentre as suas utilidades, destacam-se no setor doméstico, em que, atualmente, são utilizados principalmente em louças de mesa (aparelhos de jantar, jogos de xícaras, utensílios para acondicionar alimentos e outros).…”

Formation of metastable tetragonal zirconia nanoparticles: Competitive influence of the dopants and surface state

“…Above this temperature, the tetragonal phase is forming, which is thermodynamically stable in the bulk of zirconia up to 2380 0 C [10]. Tetragonal zirconia widely used in practice due to its active surface and smaller grain size [11,12]. This explains abundant investigations aimed at the mechanisms and development of the approaches to the high-temperature tetragonal phase stabilization zirconia at low temperatures.…”