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Tin (IV) oxide, SnO2 (cassiterite), is an n-type semiconductor with an advantageous combination of chemical, electric and optical properties that make it suitable for a range of applications, from solid-state gas sensors, transparent conductive coatings, oxidation catalysts and varistors. In varistor ceramics, grain growth studies are of particular interest, because …

Wear is one of the key problems with many types of engineering components as it can limit their life expectancy. The same is true for tools and tool steels, which are the focus of this doctoral thesis. Tool-wear response and behaviour are closely related to a material’s final microstructure and …

Nuclear fusion offers a prospect of a safe, economical and environmentally friendly source of energy. For the advanced concepts of nuclear fusion, SiC-based fibre reinforced composites were proposed as a structural material for the first wall of the reactor vessel, enabling higher operating temperatures and efficiencies. Already developed techniques for …

Sodium niobate (NaNbO3) is the end member of several alkaline niobate-based solid solutions, which represent an important group of environment-friendly lead-free piezoceramics. Even though alkaline niobates are of considerable technological importance, problems in obtaining high densities and a fine-grained microstructure are still reported and not much is known about the …

The KNN solid solution was prepared from pre-synthesized binary compounds of, sodium and potassium niobate in a 1/1 molar ratio. The KNG sintering aid was prepared by homogenizing the pre-reacted binary mixtures of alkaline reagents and germanium oxide with the Na/Ge = 1/1 and K/Ge = 1/1 molar ratios. The …

KTaO3 belongs to the group of incipient ferroelectrics, which are materials important from the fundamental, as well as from the applications, point of view. It is well known in its single-crystal form; however, the processing of technologically interesting ceramics and thin films is a challenging task and knowledge of their …

The past fifteen years has seen the rapid development of various wireless communication devices, which operate at microwave or milimeterwave frequencies (mobile phones, wireless local-area networks (LAN), Bluetooth, etc.). At the same time, this progress has stimulated the development of new materials and process technologies, which enable the size reduction …

Magnetocaloric materials are promising materials for magnetic refrigerators which would substitute present compressor refrigerators. They work on the principle of the magnetocaloric effect (MCE), where the magnetocaloric material increases its temperature when exposed to an external magnetic field. These new type of refrigerators are energetically more efficient and environmentally friendly. …

The sillenites Bi12MO20 (M = Si, Ge, Ti, Pb, Mn, B1/2P1/2) have been recognised as promising bulk materials for electronic applications because their dielectric properties (5.5 GHz: ε = 37.4 - 41, τf = -19 – (-84) ppm/K, Q x f = 800 - 8100 and Tsin = 680 - …

A starting powder with the nominal composition 0.65Pb(Mg1/3Nb2/3)O3–0.35PbTiO3 (0.65PMN–0.35PT), which corresponds to the morphotropic phase boundary (MPB) composition, was prepared by mechanochemical activation followed by attritor milling and low-temperature calcination at 700°C. It had a narrow particle size distribution with the median particle size equal to 0.3 μm. From the …