Model ferrites

This compares well with the experimentally determined value (approximately 3 x 105Am 1). The discrepancy is probably due partly to the assumption that Ni0Fe203 has the ideal inverse spinel structure and partly to the incomplete quenching of the orbital moment. 

Generally speaking, the spinel ferrites have low magnetic anisotropies and are magnetically soft exceptions are those containing Co2+ which is itself strongly 

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The model ferritic Cr steels with variation in Mn, Ti and La content were manufactured by Krupp/Thyssen NIROSTA (KTN). The main features of the various studied alloy types are given in Table 1. The studied commercial alloys, supplied by Hitachi metals, Krupp/Thyssen VDM and Rolled Alloys, respectively are listed in Table 2. For oxidation studies, samples of... 

Figure 1. Oxidation behaviour under cyclic conditions of several commercial and model ferritic steels at 800°C in air.

A more recent example is shown (Fig. 9.6) in which EFTEM has been used to characterise Cu precipitates in a Cu-containing model ferritic steel. Lozano-Perez et al. demonstrated that once the drift is characterised, line... 

Eno] Calculation (central atoms model) Ferrite and austenite phase boundaries... 

This chapter presents detailed and thorough studies of chemical synthesis in three quite different chemical systems zinc ferrite, intermetallic, and metal oxide. In addition to different reaction types (oxide-oxide, metal-metal, and metal oxide), the systems have quite different heats of reaction. The oxide-oxide system has no heat of reaction, while the intermetallic has a significant, but modest, heat of reaction. The metal oxide system has a very large heat of reaction. The various observations appear to be consistent with the proposed conceptual models involving configuration, activation, mixing, and heating required to describe the mechanisms of shock-induced solid state chemistry. 

I.I The prediction of transformation diagrams after Kirkaldy et al. (1978). A model for the calculation of ferrite and pearlite was first presented by Kirkaldy et al. (1978) based on Zener-Hillert type expressions (Zener 1946, Hillert 1957). In this first effort, no attempt was made to differentiate between the diffusive and displacive transformations and a overall C curve was produced of the type shown schematically in Fig. 11.14. Kirkaldy ettd. (1978) used the formalism below where the general formula for the time (r) to transform x fraction of austenite at a temperature T is given by... 

An analysis of the thermodynamic stability models of various nickel minerals and solution species indicates that nickel ferrite is the solid species that will most likely precipitate in soils (Sadiq and Enfield 1984a). Experiments on 21 mineral soils supported its formation in soil suspensions following nickel adsorption (Sadiq and Enfield 1984b). The formation of nickel aluminate, phosphate, or silicate was not significant. Ni and Ni(OHX are major components of the soil solution in alkaline soils. In acid soils, the predominant solution species will probably be NE, NiS04°, and NiHP04° (Sadiq and Enfield 1984a). 

Methylene blue was used as a model drug, and matrices were based upon crosslinked copolymers of sodium acrylate or polymer composites of ferrite. 

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