Peter G. Laye

Studies on the ageing of a magnesium-potassium nitrate pyrotechnic composition using isothermal heat flow calorimetry and thermal analysis techniques

The ageing behaviour of a pyrotechnic mixture of magnesium and potassium nitrate has been followed at 50 °C and 65% relative humidity by isothermal heat flow calorimetry. Measurements have been carried out with samples in air and in an inert atmosphere. The main reaction product was found to be magnesium hydroxide. This has been determined quantitatively by thermogravimetry and the amount formed correlated with the measured cumulative heat of ageing. The results have been compared with those obtained for magnesium powder studied under the same conditions. In addition the influence of the ageing process on the pyrotechnic reaction has been studied by high temperature differential scanning calorimetry under ignition conditions and modulated temperature differential scanning calorimetry.

Cyclic voltametry and differential scanning calorimetry of lubricating oils: amine antioxidants

Abstract The use of cyclic voltametry for the determination of dioctyldiphenylamine in three different types of lubricating oils has been investigated. The electrochemical measurements were made using a three-electrode configuration with the oils dissolved in a mixture of methylene chloride and tetrabutylammonium perchlorate. The analytical results are obtained from the experimental data using a convolution procedure in which the concentration of the antioxidant is determined from the limiting value of the convoluted current. The results are compared with those obtained from differential scanning calorimetry where the overall oxidative stability is measured.