Platinum-iron magnets

Platinum-cobalt and platinum-iron magnets. These alloys are isotropic corrosion resistant, ductile, and hence easy to machine. Their magnetic properties are superior to most other permanent magnet materials except that of Nd-Fe-B. Due to the expensive price of platinum, they were replaced by Nd-Fe-B. 

The magnetic criterion is particularly valuable because it provides a basis for differentiating sharply between essentially ionic and essentially electron-pair bonds Experimental data have as yet been obtained for only a few of the interesting compounds, but these indicate that oxides and fluorides of most metals are ionic. Electron-pair bonds are formed by most of the transition elements with sulfur, selenium, tellurium, phosphorus, arsenic and antimony, as in the sulfide minerals (pyrite, molybdenite, skutterudite, etc.). The halogens other than fluorine form electron-pair bonds with metals of the palladium and platinum groups and sometimes, but not always, with iron-group metals. 

Mossbauer spectroscopy is a specialist characterization tool in catalysis. Nevertheless, it has yielded essential information on a number of important catalysts, such as the iron catalyst for ammonia and Fischer-Tropsch synthesis, as well as the CoMoS hydrotreating catalyst. Mossbauer spectroscopy provides the oxidation state, the internal magnetic field, and the lattice symmetry of a limited number of elements such as iron, cobalt, tin, iridium, ruthenium, antimony, platinum and gold, and can be applied in situ. 

For a comparison of experimental Mossbauer isomer shifts, the values have to be referenced to a common standard. According to (4.23), the results of a measurement depend on the type of source material, for example, Co diffused into rhodium, palladium, platinum, or other metals. For Fe Mossbauer spectroscopy, the spectrometer is usually calibrated by using the known absorption spectrum of metallic iron (a-phase). Therefore, Fe isomer shifts are commonly reported relative to the centroid of the magnetically split spectrum of a-iron (Sect. 3.1.3). Conversion factors for sodium nitroprusside dihydrate, Na2[Fe(CN)5N0]-2H20, or sodium ferrocyanide, Na4[Fe(CN)]6, which have also been used as reference materials, are found in Table 3.1. Reference materials for other isotopes are given in Table 1.3 of [18] in Chap. 1. 

Fig. 3.10. Reaction cell. 1 - Atom gun 2 - Thermostate 3 - Metal evaporator 4 - Pt/Pt-Rh thermocouple 5/7 - Collimation holes (diameter 3 mm) 8 -Shutter 9 - ZnO semiconductor sensor 10 - Mobile quartz weight 11 - Platinum contacts terminals 12 - Vitrificated iron bars controlled by a magnet 13 -Quartz guides...

Slow-cooled matte A process for extracting platinum metals from copper-nickel matte. The molten matte is cooled slowly, over several days. This causes the platinum metals to enter a nickel-iron phase which can be separated magnetically from the other components. Operated by Rustenberg Platinum Mines in South Africa, and INCO in Canada. 

Nonsteroidal antiinflammatory drugs, interaction with lithium, 36 66 No-phonon transition, 35 324 Norbomadiene complexes with cobalt, 12 286 with copper, 12 328, 330, 331 with gold, 12 348, 349 with group VIB metals, 12 231 with group VnB metals, 12 241 with iron, 12 265 with palladium, 12 314 with platinum, 12 319 with rhodium, 12 300-302 with ruthenium, 12 278, 279 with silver, 12 340-342, 344, 346 Norbomylsiloxane, 42 226, 228 Notch receptor proteins, 46 473, 475 h (N)" oxime complexes, osmium, 37 260 h (N,0) oxime complexes, osmium, 37 260 (NPr ljiFeCfrdto),], magnetization versus temperature, 43 230... 

Iron-platinum and similar materials require a lot of energy to alter their magnetic properties, making these substances stable and a good... 

If one looks along the strip in the direction of the current, with the magnetic lield directed downward, then, with si rips of antimony, cohall, zinc, or iron, the electric potential drop is toward the right and the effect is said to he positive. With gold, silver, platinum, nickel, bismuth, copper, and aluminum, it is toward the left, and Ihe effect is called negative. The transverse electric potential gradient per anil magnetic lield intensity per unit current density is called the Hall coefficient" for the metal in question Thus, the Hall coeflicienL is delined us... 

Fig. 7. Mossbauer spectra of oxidized plant-type iron-sulfur proteins in zero applied magnetic field. Abbreviations AZI = A zotobacter Fe-S protein I, 4.6°K AZII = Azoiobacter Fe-S protein II, 4.2 °K Put. = Putidaredoxin, 4.2 °K Ad.— Pig Ad-renodoxin, 4.2 °K Clos. = Clostridial paramagnetic protein, 4.2 °K PPNR = Spinach ferredoxin, 4.5 °K Parsley = Parsley Ferredoxin, 4.2 °K. Velocity scale is relative to iron in platinum...

The thermostat is an iron box about thirty centimeters square filled with molten lead. An iron blade keeps the lead stirred and a platinum resistance thermometer functions both as a thermometer and as a thermoregulator. The Wheatstone bridge, which contains the resistance thermometer as one arm, is adjusted for a given temperature, and the beam of light from the galvanometer strikes a zero reading on the scale. At this position is introduced a photoelectric cell connected with a radio tube and amplifier, which in turn actuates an electro-magnetic relay. When the temperature reaches the predetermined value, the beam of... 

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