Platinum-iron alloys

Iron-platinum alloy nanoparticles are very promising candidates for future data storage systems. They become available by simultaneous reduction of platinum acetylacetonate and the decomposition of Fe(CO)5 in oleic acid and oleyl amine.The composition of FexPti x can be varied between X = 0.48 and x = 0.7. The particles exhibit disordered fee structure. They are superparamagnetic at room temperature. Aimealing at 550-600 °C transforms the fee structure into a face-centered tetragonal (fet) one. These have been shown to be suited for storage devices owing to their room temperature coercivity. The exact transition temperature depends on the stoichiometry. 

Carpenter, E.E., Sims, J.A., Wienmann, J.A., Zhou, W.L., O Connor, C.J. Magnetic properties of iron and iron platinum alloys synthesized via microemulsion techniques. 1. Appl. Phys. 87, 5615-5617 (2000)... 

The corrosion behaviour of amorphous alloys has received particular attention since the extraordinarily high corrosion resistance of amorphous iron-chromium-metalloid alloys was reported. The majority of amorphous ferrous alloys contain large amounts of metalloids. The corrosion rate of amorphous iron-metalloid alloys decreases with the addition of most second metallic elements such as titanium, zirconium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, nickel, copper, ruthenium, rhodium, palladium, iridium and platinum . The addition of chromium is particularly effective. For instance amorphous Fe-8Cr-13P-7C alloy passivates spontaneously even in 2 N HCl at ambient temperature ". (The number denoting the concentration of an alloy element in the amorphous alloy formulae is the atomic percent unless otherwise stated.)... 

It must be appreciated that at high temperatures platinum permits the flame gases to diffuse through it, and this may cause the reduction of some substances not otherwise affected. Hence if a covered crucible is heated by a gas flame there is a reducing atmosphere in the crucible in an open crucible diffusion into the air is so rapid that this effect is not appreciable. Thus if iron(III) oxide is heated in a covered crucible, it is partly reduced to metallic iron, which alloys with the platinum sodium sulphate is similarly partly reduced to the sulphide. It is, advisable, therefore, in the ignition of iron compounds or sulphates to place the crucible in a slanting position with free access of air. 

Palladium electrocatalysts, 183 Palladium-alloy electrocatalysts, 298-300 Pareto-optimal plot, 85 Platinum-alloy electrocatalysts, 6, 70-71, 284-288, 317-337 Platinum-bismuth, 86-87, 224 Platinum chromium, 361 362 Platinum-cobalt, 71, 257-260, 319, 321-330, 334-335 Platinum-iron, 319, 321, 334-335 Platinum-molybdenum, 253, 319-320... 

Silvery, shiny, and hard. Unique metal, gives off an odor as it forms volatile 0s04 on the surface (oxidation states 81). Osmium is the densest element (22.6 g cm3 record ). Was replaced in filaments (Osram) by the cheaper tungsten. Used in platinum alloys and as a catalyst. Haber s first catalyst in ammonia synthesis was osmium, which fortunately could be replaced by doped iron. The addition of as little as 1 to 2 % of this expensive metal increases the strength of steel (e.g. fountain-pen tips, early gramophone needles, syringe needles). 

It is further important to note that all the current/voltage characteristics depicted in Fig. 6 are unchanged by the presence of liquid fuels such as methanol, formaldehyde, formic acid, or hydrazine. The phthalocyanine electrode remains completely inert toward such substances. For this reason, no mixed potential can be formed at a phthalocyanine electrode, as for example can occur at a platinum electrode, when it is used as cathode in a methanol cell containing sulfuric acid. This is shown by a comparison (see Fig. 7) of the stationary characteristics of the platinum alloy we found to be the most active in the presence of methanol, namely a Raney ruthenium—rhodium electrode, with an iron phthalocyanine electrode, both measured in 4.5 N H2SO4+2M CH3OH. 

Niokel and iron combine and form a very hard alloy, which is that found in meteoric stones. 1 Cobalt, copper, silver, gold, platinum, palladium, and. other more rare metals, all combine in small proportions with iron, producing alloys of no known. value in the arts. 

Inconel, a nickel-iron-chromium alloy, is normally used in manufacturing the RTD sheath because of its inherent corrosion resistance. When placed in a liquid or gas medium, the Inconel sheath quickly reaches the temperature of the medium. The change in temperature will cause the platinum wire to heat or cool, resulting in a proportional change in resistance. 

Concentrated sulphur acid evaporation and dehydration is performed in a group of two heat exchangers with important exchange surface (up to 1 340 m2) (HX-208). The S03/S02 decomposition reactor (HX-209) is a set of five reactors with two reactive zones. The first one, with a temperature of 875 K requires a platinum catalyst and the second one an iron-oxide catalyst. The operating temperature in the second zone increases up to 1125 K. Due to operating conditions (temperature, chemical composition), these three devices require a nickel-iron-chromium alloy. Then sulphur trioxide recombination reactor consists of a packed column (HX-210). Required investment for S03 conversion is estimated about EUR(08) 508.6 M. 

Platinum Alloy Electrocatalyst and Acid-Electrolyte Fuel Cell Electrode Using The Same Iron-Cobalt on Conductive Carrier, File date 24 June 1987, Issue date 27 Dec 1988. 

In Raney s method a catalytically active metal is alloyed with a catalytically inactive one and then treated with a reagent that dissolves out the inactive metal. The catalytically inactive component that is to be dissolved out may be aluminum, silicon, magnesium, or zinc. The catalytically active metal is usually nickel, cobalt, copper, or iron. Noble-metal catalysts can, however, also be produced by Raney s method if an aluminum-platinum alloy (40% of platinum) or a zinc-palladium alloy (40% of palladium) is decomposed by hydrochloric acid.153... 

An interesting approach to synthesize metal alloy nanocrystals is the use of simultaneous salt reduction and thermal decomposition processes. Sun et al. [18] reported on the synthesis of iron-platinum (FePt) nanoparticles through the reduction of platinum acetylacetonate by a diol, and decomposition of iron pentacarbonyl (Fe(CO)5) in the presence of a surfactant mixture (oleic acid and oleyl amine). On the basis of a similar approach, Chen and Nikles [217] synthesized ternary alloy nanoparticles (FC cCo3,Ptioo x-y), using a simultaneous reduction of acetylacetonate and platinum acetylacetonate and thermal decomposition of Fe(CO)5 and obtaining an average particle diameter of 3.5 nm and narrow particle size distribution. 

The synthetic approach developed for the synthesis of platinum-iron binary alloy nanopartides was subsequently adopted for the preparation of several other binary alloy nanopartides, such as FePd [90] or MnPt [91]. However, these alloys required further structural characterization, as well as further developments of the methods for controlling the partide size, shape, and composition. 

Platinum alloy catalysts have been found to improve the oxygen reduction kinetics. Shrinking of the Pt-Pt distance as well as electronic effects have been used to explain this phenomenon. Alloying of platinum with non noble metals such as cobalt, nickel or iron after extended contact with acid electrolytes left platinum rich skins on the surface, still providing improved kinetics. Pathways of the nrai... 

Anhydrous phosgene in the liquid state is compatible with a variety of common metals, including aluminum (of 99.5 percent purity), copper, pure iron or cast iron, steel (including cast steel and chrome-nickel steels), lead (up to 250°F or 12 PC), nickel, and silver it is also compatible with platinum and platinum alloys in instruments. Nonmetallic materials with which liquid anhydrous phosgene is also compatible include acid resistant linings (ceramic plates and carbon blocks), enamel on cast iron or glass-lined steel, Pyrex or Kimax, porcelain, quartzware, granite or basalt natural stone, stoneware, and Teflon. 

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