Cobalt-nickel ferrite

Regazzoni, A.E. Matijevic, F. (1983) Formation of uniform colloidal mixed cobalt nickel ferrite particles. Colloids Surfaces 6 189—... 

In a similar manner, uniform spherical particles of nickel ferrite (NiFe204) (6), cobalt ferrite (CoFe204) (7), and cobalt-nickel ferrite (CorNi vFe204) (8) were prepared as well. 

Gonsalves, L.R., Mojumdar, S.C., and Verenkar, V.M.S. (2010) Synthesis of cobalt nickel ferrite nanoparticles via autocatalytic decomposition of the precursor. Journal of Thermal Analysis and Calorimetry, 100, 789-792. 

Good results are obtained with oxide-coated valve metals as anode materials. These electrically conducting ceramic coatings of p-conducting spinel-ferrite (e.g., cobalt, nickel and lithium ferrites) have very low consumption rates. Lithium ferrite has proved particularly effective because it possesses excellent adhesion on titanium and niobium [26]. In addition, doping the perovskite structure with monovalent lithium ions provides good electrical conductivity for anodic reactions. Anodes produced in this way are distributed under the trade name Lida [27]. The consumption rate in seawater is given as 10 g A ar and in fresh water is... 

A number of ferrites have been subjected to shock modification and studied with x-ray diffraction as well as static magnetization and Mossbauer spectroscopy [87V01], Studies were carried out on cobalt, nickel, and copper ferrites as well as magnetite (iron ferrite). 

The addition of cobalt to a nickel ferrite has been employed to increase resistivity, as illustrated in Fig. 9.24. For an explanation it is necessary to consider the third ionization potentials of chromium, iron, manganese, cobalt and nickel, which increase in this order. The addition of cobalt tends to maintain the iron in the Fe3+ state by virtue of the equilibrium... 

I. Preparation of Reduced Iron (Cobalt, Nickel) (245). 2. Pr ara-tion of Pyrophoric Iron (246). 3. Preparation of Iron(II) Oxide (246). 4. Preparation of Macrocrystalline Iron(III) Oxide (246). 5. Preparation of Nickel(III) Oxide (247). 6. Preparation and Properties of Sodium Ferrite (247). 7. Preparation of Anhydrous Cobalt (Nickel) Chloride in an Ethanol Solution (247). 8. Preparation of Anhydrous Iron(IlI) Chloride in a Fluidized Bed (247). 9. Preparation of Potassium Trioxalatoferrate(III) (247). 10. Preparation of Tetraamminecarbonatocobalt(III) Nitrate (248). 

Strong Attraction Steels carbon, alloy, tool Cast Irons gray, ductile, malleable Cobalt Nickel Stainless Steels ferritic, duplex, martensitic, martensitic precipitation hardening... 

Metal Oxides. Iron, cobalt, nickel oxides, and some ferrites ligated with long chain fatty acids. 

Natural rubber composites containing nickel-cobalt-zinc ferrite 11401... 

As a very important topic in contamination buildup, the question is still open to what extent the data on corrosion product solubilities in the primary coolant are of importance for the behavior of trace amounts of cobalt. It seems to be still questionable whether cobalt ferrites as a well-defined compound with properties similar to the nickel ferrites can exist under PWR primary coolant conditions, whether cobalt atoms can be incorporated into a nickel ferrite lattice or whether traces of cobalt may be deposited onto the surfaces of the reactor core by adsorption on other, already deposited oxides. Such adsorption processes may occur even on the Zircaloy oxide films in the absence of any net deposition of corrosion products. Experimental investigations of the interaction of dissolved cobalt with heated Zircaloy surfaces (Lister et al., 1983) indicated that at low crud levels in the coolant cobalt deposition on surfaces is dominated by processes involving dissolved species, with adsorption/desorption processes being the responsible mechanisms. The extent of cobalt deposition is controlled by the type of oxide present on the Zircaloy surface thin black films of zirconium oxide will pick up less cobalt from the solution than thick white oxide films, even when the differences in the available surface areas of both types of oxides are taken into account. The deposition process seems to be little affected by the heat flux in the exposed metal. According to Thornton (1992), such adsorption-desorption exchange processes provide a pathway for radioactive species to be transported around the circuit even when the net movement of corrosion products is minimized this means that under such circumstances the processes of activity transport and of corrosion product transport may be decoupled. They may provide a pathway for target nuclides such as Co to be adsorbed onto fuel rod surfaces even in a core which is virtually free of deposited corrosion product particles. 

A direct experimental detection of the state of cobalt traces in the particulate corrosion products is very difficult to obtain. One practical reason for this difficulty is the cobalt concentration, which is usually far too low for the usual structure analysis methods such as X-ray identification of the prevailing chemical compound moreover, the similarity of the crystallographic data of cobalt and nickel ferrites to those of Fe304 complicates the interpretation of the analytical results. However, there are two observations which raise doubts about whether the above-mentioned assumption of cobalt incorporation from the primary coolant into the... 

Other studies have indicated that nickel, which is incorporated into the superficial oxide layers on Incoloy 800 steam generator tubes, is present there in the form of neutral atoms. Schuster et al. (1988) analyzed contamination layers from different PWR plants using AES and XPS techniques their results showed, besides an almost homogeneous Co distribution over the whole thickness of the oxide layers, that they consist of a Cr-Fe spinel in which, with the exception of the uppermost regions (some nanometers), nickel is exclusively present in its atomic state and not as a chemically bound constituent of a nickel ferrite. The existence of Ni imder the conditions prevailing in the PWR primary circuit can be explained by thermodynamic causes. By analogy, it seems justifiable to assume that cobalt... 

Ferrite A ceramic material made of powdered and compressed ferric oxide, plus other oxides (mainly cobalt, nickel, zinc, yttrium-iron, and manganese). These materials have low eddy current losses at high frequencies. 

Thermal conductivity studies have been conducted on a wide range of filled polymers and composites, including carbon fibers [62-68], aluminum powder [65], nitride [66], magnetite, barite, talc, copper, strontium ferrite [67], glass fiber-filled polypropylene and manganese or iron-filled polyaniline, carbon nanotubes [68], and nickel-cobalt-zinc ferrite in natural rubber [70]. 

Ferrite is a ceramic material with the general formula MO Fe Oj where M may be manganese, iron, cobalt, nickel or zinc. Ferrite is magnetic with poor electrical con-... 

Soft magnetic materials are characterized by high permeabiUty and low coercivity. There are sis principal groups of commercially important soft magnetic materials iron and low carbon steels, iron—siUcon alloys, iron—aluminum and iron—aluminum—silicon alloys, nickel—iron alloys, iron-cobalt alloys, and ferrites. In addition, iron-boron-based amorphous soft magnetic alloys are commercially available. Some have properties similar to the best grades of the permalloys whereas others exhibit core losses substantially below those of the oriented siUcon steels. Table 1 summarizes the properties of some of these materials. 

Plain chromium, ferritic steels are much more resistant and for a time were considered virtually immune to stress-corrosion cracking. It is now known that failure can be caused, especially if the steels contain addition of copper, cobalt or nickel. Even so, resistance is superior to that of the standard austenitics, and ferritics are used where stress-corrosion cracking of the austenitic grades could be a possibility . 

A typical hexagonal ferrite is BaFei Oiy- Again, oilier magnetic ions, such as manganese, cobalt, and nickel may be introduced lo produce wide variations in M and T Hexagonal ferriles are characterized by large... 

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