A method for the determination of molybdenum in steel, based on catalytic electroreduction by the molybdate ion, is described. After a suitable sample dissolution, iron is removed by cation exchange and molybdenum is eluted with 0.5 M nitric acid. Tbe eluate is diluted 1 + 1 with 4 M ammonium nitrate solution, and polarographic analysis carried out over the range from 0 to -1.0 V versus a saturated calomel electrode. The method is applicable to the determination of molybdenum in the 0.001-5% of molybdenum range and good agreement is reported for a number of certified British Chemical Standard and commercial steels.

The curing of a commercial ethoxymethyl-phosphosiloxane at different temperatures and under various gas ambients was characterised using NMR, thermoanalytical techniques, and FTIR spectroscopy. DSC (Differential Scanning Calorimetry) and DTG (Differential Thermo Gravimetry) were employed to characterize the reactions that occur during thermal treatments in O2 or N2 atmospheres. FTIR spectroscopy and CP (Cross Polarization) 133C - NMR were used to detect the presence of the hydroxyl and organic groups in the cured samples. The experimental results identified three different temperatures (400,580,700°C) that define important stages of the curing reaction. In particular, for annealing at temperatuires up to 580°C in 02, DSC, DTG and FTIR spectra showed the elimination of the organic groups. However, when the annealing was carried out in N2 up to 700°C, these groups are retained.

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