Showing papers on "Cobalt published in 1971"

The Magnetization of Pure Iron and Nickel

Abstract: The saturation magnetizations of very pure iron and nickel have been measured absolutely by a force method at room temperature. The values are 217.6 and 55.1 emu/g (217.6 and 55.1 J T -1 kg -1 ) respectively. The theory and reliability of the force method are investigated and discussed. New measurements have also been made by a relative method on the same materials at temperatures ranging from 4 K to above the respective Curie temperatures of iron and nickel. Reduced magnetization, temperature data have been derived and are compared with those already available for face centred cubic cobalt.

A cobalt induced cleavage reaction and a new series of arenecobalt carbonyl complexes

Abstract: Reaction of bicyclo[2,2,1]hepta-2,5-diene with alkynedicobalt hexacarbonyls in inert solvents gives dicarbonylcyclopentadienylcobalt, but in aromatic hydrocarbons arene-nonacarbonyltetracobalt complexes are formed.

Analytical Study of the Lead Ion-selective Ceramic Membrane Electrode

Abstract: The lead(II) ion-selective ceramic membrane electrode developed by sintering a mixture of lead, silver, and cuprous sulfides showed sensitivity, selectivity, and other response characteristics well suited to analytical utilization. The Nernstian slope was obtained over a concentration range from 10−1 to 10−6M Pb2+ in activity, and the analytical range had a concentration of 10−1–10−7M when the membrane contained less than 30 wt% of cuprous sulfide and more than 1 wt% of lead sulfide. Among the common ions, silver, cupric, mercury(II), ferric, sulfide and iodide ions interfered seriously. About 10 times as many cadmium and bromide ions and more than 1000 times as many alkali metal, alkaline earth metal, zinc, aluminum, nickel, manganese(II), cobalt, and nitrate ions did not interfere with the lead ion, however. The electrode potentials did not change over a pH range from 2 to the pH at which the precipitation of lead hydroxide occurred. The electrode was safely used at temperatures from 0 to 95°C, and the ...

Sensitized substrates for chemical metallization

Abstract: There are provided new articles of manufacture, suitable for the production of metallized bodies, such as printed circuits, dials, nameplates, metallized plastics, glass, ceramics and the like, comprising bases coated with a layer of copper, nickel, cobalt or iron salts or salt compositions, which on exposure to radiant energy, such as heat, light, etc., or chemical reducing agents is converted to a layer of metal nuclei which is non-conductive, but which is capable of catalyzing the deposition of metal onto the base from an electroless metal deposition solution in contact with the metal nuclei.

Probable formation of 13-atom polyhedral complexes containing B10C2H122- and cobalt

Abstract: : The probable formation of a 13-atom polyhedral complex containing the B10C2H12(-2) ion, C5H5(-) ion and formal cobalt (III) is discussed together with its progressive rearrangement to two isomeric species. (Author)

Cobalt base coating for the superalloys

Abstract: THE OXIDATION-EROSION AND SULFIDATION RESISTANCE OF THE NICKEL-AND COBALT-BASE SUPERALLOYS IS MARKEDLY IMPROVED THROUGH THE USE OF A COATING CONSISTING OF COBALT,CHROMIUM, ALUMINUM AND AN ACTIVE METAL SUCH AS YTTRIUM, PARTICULARLY AT THE COMPOSITION, BY WEIGHT, BY OF 15-40 PERCENT CHROMIUM, 10-25 PERCENT ALUMINUM, 01-5 PERCENT YTTRIUM, BALANCE COBALT

Sintered Diamond Compacts with a Cobalt Binder

Abstract: Diamond powder can be successfully cemented with cobalt. At 62 kilobars the sintering occurs over the temperature range from 1570 degrees to 1610 degrees C. The maximum microhardness of the compact ( 3000 kilograms per square millimeter on the Knoop scale) is obtained with a mixture of 20 percent cobalt (by volume) and a diamond particle size of 1 to 5 micrometers.

Studies on the magnetic cross-over in five-co-ordinate complexes of iron(II), cobalt(II), and nickel(II). Part II

Abstract: The new terdentate ligand 2,6-di(diphenylphosphinomethyl)pyridine forms a series of crystalline complexes, MLX2, with iron(II), cobalt(II), and nickel(II) halides and thiocyanates. Distorted square pyramidal structures are suggested on the evidence of their electronic spectra and other physical properties. Magnetic susceptibility measurements as a function of temperature classify the cobalt and nickel compounds as low-spin, high-spin, or as having an anomalous temperature-dependence. For the latter group a low-spin ⇌ high-spin equilibrium is suggested. All the iron complexes are fully high-spin over the temperature range studied. The suggested magnetic cross-over in these compounds is discussed in relation to that in previously reported compounds having a distorted trigonal bipyramidal structure.

Determination of eleven metals in small samples of blood by sequential solvent extraction and atomic-absorption spectrophotometry

Abstract: A method is described for the determination of eleven metals in a 1-ml solution of an oxidised blood sample. The metals iron, copper, bismuth, zinc, cadmium, lead, cobalt, nickel, manganese, strontium and lithium are selectively extracted into small (0·30 to 0·50 ml) volumes of isobutyl methyl ketone as their chelates or ion-association complexes, and are determined in the organic phases by atomic-absorption spectrophotometry. The enhancement effect of the organic solvent combined with the extraction and concentration of the metals results in average sensitivity increases of seven times that obtained by a direct determination on the aqueous solutions.The recovery of the metals added to blood is quantitative and, with two exceptions (lead and bismuth), a precision of better than 8 per cent. can be achieved at the 0·1 p.p.m. level.The results are given of an application of the method to a study of the problem of metal ingestion by children who have pica.

Structural and Magnetic Characteristics of Th-Co and Th-Fe Compounds

Abstract: The Th–Co and Th–Fe systems were studied by x‐ray diffraction methods Five intermetallic compounds were observed in each system For each of these compounds the lattice parameters were determined The magnetic properties of the various compounds were investigated at temperatures between 42 and 1200 K with magnetic field strengths up to 30 kOe In the Th–Co system the compounds Th2Co17 and ThCo5 are ferromagnetic; the Curie temperature and the cobalt moment decrease rapidly with Th‐content The compounds Th2Co7, ThCo, and Th7Co3 are paramagnetic In the Th–Fe system the compounds Th2Fe17, ThFe5, Th2Fe7, and ThFe3 are ferromagnetic; with increasing Th content the Curie temperatures and iron moments first rise, then decrease The compound Th7Fe3 is paramagnetic A comparison is made with the magnetic properties of rare‐earth‐iron and ‐cobalt compounds Magnetic data are reported for La3Co, Y3Co, and YCo2 which are paramagnetic Curie temperatures are also given for YCo3 and YCo5

Precipitation-hardening characteristics of ternary cobalt - aluminum - x alloys

Abstract: Five precipitation-hardenable ternary cobalt-base alloy systems containing 4.25 weight percent aluminum with titanium, niobium, tantalum, molybdenum,. and tungsten as the third element were melted and evaluated as to their precipitation-hardening characteristics. Hardening phases were electrolytically extracted from alloys aged up to 1000 hours in the 600°C to 900°C temperature range. Based upon the evaluation of these systems, three quartenary alloys with compositions Co-4Al-15Cr-10Ta, Co-4Al-15Cr-20Mo, and Co-4Al-15Cr-25W were melted and simi­ larly evaluated after aging for times from 0.1 to 1000 hours at 800°C. The results of the investigation of the ternary al­ loys showed that Ti additions promoted the highest percent­ age increase in hardness, but that overaging of the AlC^Ti hardening phase was very rapid. The effects of the Nb and Ta additions to the Co-4Al matrix were somewhat similar in that both were considerably more effective as solid solution strengtheners than as pre­ cipitation hardening agents. Hardening in the Ta alloys was the result of the presence of primary and precipitated yCo2Ta (MgNi2 type) which, upon aging, transformed to the cubic xi aCo-jTa. Similarly, in the alloys containing Nb, the Laves phase Co2Nb (MgK^ type) was generally present. Two phases previously reported in the literature for the Co-Nb binary system were confirmed. The Co-4Al-5Nb alloy aged for 1000 hours at 700°C contained an ordered fee phase with O aQ = 3.655 A, while this same alloy aged at 800°C contained O a hexagonal phase having the parameters a = 5.9 4 A and c = 6.89 A. The cellular precipitation of Co^Mo in the Co-Al-Mo alloys produced very high hardnesses in that alloy system. Temperatures of 900°C were required to overage these struc­ tures within the 1000-hour test interval. In the Co-Al-W systems, an ordered fee superlattice, O or coherent precipitate, having a parameter of aQ = 3.5 95 A was found. Precipitation of this phase resulted in continu­ ous increases in hardness for aging times up to 1000 hours at 800°C. Additions of 15 weight percent Cr to the basic Co-4Al-10Ta, Co-4Al-20Mo, and CO-4A1-25W alloys changed their aging behavior; and in the case of the latter two al­ loys, the R and Mu phases, respectively, appeared. Aluminum additions to alloys of Co containing the refractory metals or Ti generally result in a stabilization of the fee Co matrix and a resulting decrease in the tend­ ency for the formation of non-cubic phases in the matrix. This effect seemed especially strong in the alloys containing

Synthesis of N-acyl amino-acids by a carbonylation reaction

Abstract: A novel cobalt carbonyl-catalysed reaction gives an N-acyl amino-acid from an aldehyde, an amide, and carbon monoxide.