Diopside, CaO.MgO.2SiO2, and glasses of the same stoichiometry are fundamental phases in non-ferrous slags. Samples of this composition, prepared from the melt at different cooling rates, were examined via DTA and IR spectra. A correlation was found between the degree of vitrification and the magnitude of the exothermic effect at around 870 °C. The same dependence exists for some slags. No exotherm was observed for well-crystallized samples. The reactivity with water was assigned to the glass content.
The Piloyan activation energiesE of decomposition and the initial temperaturesTD of the exotherms of hexanitrobiphenyl (HNB), nonanitro-m-terphenyl (NONA), tripicryl-s-triazine (TPT) and 1,4,5,8-tetranitronaphthalene (TENN) have been determined by means of non-isothermal DTA. Due to its volatility in the zone of the beginning of thermal decomposition onlyTD values are specified fors-trinitrobenzene (TNB). From the values ofE ·TD−1 for HNB and from the derived values ofE ·TD−1 for TNB on the one hand, and from the published values of the Arrhenius parameters obtained by means of the manometric method on the other, relationships have been derived. The relationship betweenE ·TD−1and the standard activation enthropy is considered relevant.
The application of DTA to fluxed melts is discussed, and an apparatus for the determination of the solubility of crystalline materials in molten solutions is described. An exploratory study of the crystallization of nickel ferrite from barium borate fluxes is also described, and solubility curves are presented for fluxes which favour crystal growth. The heat of solution of nickel ferrite was found to be 73 ± 2 Kjoule mole−1.
Conditions are presented for application of the Piloyan method to the DTA of poly-nitro aromatic compounds. Activation energies (E) of the thermal decomposition and the initial valuesTD of the exotherms are determined for trinitrotoluene, trinitro-m-xylene, trinitromesitylene, picryl chloride and dichlorotrinitrobenzene. Linear relationships are derived between the termsE · T