Composite particles iron-nickel alloy

The composition of the codeposition bath is defined not only by the concentration and type of electrolyte used for depositing the matrix metal, but also by the particle loading in suspension, the pH, the temperature, and the additives used. A variety of electrolytes have been used for the electrocodeposition process including simple metal sulfate or acidic metal sulfate baths to form a metal matrix of copper, iron, nickel, cobalt, or chromium, or their alloys. Deposition of a nickel matrix has also been conducted using a Watts bath which consists of nickel sulfate, nickel chloride and boric acid, and electrolyte baths based on nickel fluoborate or nickel sulfamate. Although many of the bath chemistries used provide high current efficiency, the effect of hydrogen evolution on electrocodeposition is not discussed in the literature. 

Alloys are prepared commercially and in the laboratory by melting the active metal and aluminum in a crucible and quenching the resultant melt which is then crushed and screened to the particle size range required for a particular application. The alloy composition is very important as different phases leach quite differently leading to markedly different porosities and crystallite sizes of the active metal. Mondolfo [14] provides an excellent compilation of the binary and ternary phase diagrams for aluminum alloys including those used for the preparation of skeletal metal catalysts. Alloys of a number of compositions are available commercially for activation in the laboratory or plant. They include alloys of aluminum with nickel, copper, cobalt, chromium-nickel, molybdenum-nickel, cobalt-nickel, and iron-nickel. 

In recent years, we have seen an explosive interest in nanomaterials, in particular in nanofibers, nanofilaments, and nanotubes of the very different chemical composition. The interest arises from the specific mechanical and physicochemical properties of these nano objects, which allow them to be used, for example, as specific adsorbents, catalyst supports, reinforcing components of composite materials, and so on. The most cited generic types of nanomaterials are carbon nanofilaments and nanotubes. Numerous methods for preparing these carbon materials are known. However, the simplest method seems to be thermal pyrolysis of various carbon contain ing precursors (e.g., carbon monoxide, saturated and unsaturated hydro carbons, etc.) in the presence of special catalysts that are typically nanosized particles of nickel, cobalt, iron metals, or their alloys with different metals. 

With iron-nickel segregation is much less likely. Accordingly the XRD results of the nickel-iron catalysts point to a homogeneous phase, in which iron and nickel atoms have been randomly distributed over f.c.c. lattice positions. The experimental lattice parameter of the supported Ni-Fe catalysts allowed us to cdculate the chemical composition of the alloy particles. Using data collected by Pearson [2], we calculated for the nickel content of the three nickel-iron alloy catalysts 51.9, 59.9, and. 5 at.%, which agrees very well with the contents of 50.0, 60.0, and 66.7 at.% calculated from the stoichiometry of the nickel-iron cyanide complexes. 

An important appHcation of MMCs in the automotive area is in diesel piston crowns (53). This appHcation involves incorporation of short fibers of alumina or alumina—siHca in the crown of the piston. The conventional diesel engine piston has an Al—Si casting alloy with a crown made of a nickel cast iron. The replacement of the nickel cast iron by aluminum matrix composite results in a lighter, more abrasion resistant, and cheaper product. Another appHcation in the automotive sector involves the use of carbon fiber and alumina particles in an aluminum matrix for use as cylinder liners in the Prelude model of Honda Motor Co. 

We speak of a direct conversion when there is an alteration of the chemical structure of the material in the wake of a reaction of decomposition of the original material, MX, in a composite electrode comprising nanoparticles of metal M° encapsulated in a LiX matrix. There is no formation of a lithiated metal alloy as before, but rather of metal particles which are inactive in comparison to lithium. The reaction leads to the formation of a metastable compound LiX (essentially Li20). In theory, this compound which is formed is not stable, but it is considered to be so because of its very slow rate of transformation. Many transition-metal oxides are involved oxides of cobalt CoO and C03O4, of copper CuO, of nickel NiO and of iron FeO and Fc203. Other compounds such as NiPs and FeS2 can also be considered. 

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