The reaction mechanism between electroless Ni–P and Sn was investigated to understand the effects of Sn on solder reaction-assisted crystallization at low temperatures as well as self-crystallization of Ni–P at high temperatures. Ni3Sn4 starts to form in a solid-state reaction well before Sn melts. Heat of reaction for Ni3Sn4 was measured during the Ni–P and Sn reaction (241.2 J/g). It was found that the solder reaction not only promotes crystallization at low temperatures by forming Ni3P in the P-rich layer but also facilitates self-crystallization of Ni–P by reducing the transformation temperature and heat of crystallization. The presence of Sn reduces the self-crystallization temperature of Ni–P by about 10 °C. The heat of crystallization also decreases with an increased Sn thickness.
Mg ion conductors, MgAl2O4 and MgZr4(PO4)6, were prepared by solid state reaction. Their electrical properties were measured and their application in electrochemical sensors for on-line determination of Mg in molten Al in the refining process and alloying process was examined. The activation energies for Mg ion conduction in MgAl2O4 and MgZr4(PO4)6 are 2.08 eV and 1.7 eV, respectively. The sensors have been found to respond rapidly to the change of Mg content in molten aluminium around 1000 K.
A procedure of smectite containing clay enrichment has been optimized, and the process of sedimentation has been studied. The new enrichment based method for quantitative determination of clay fraction in smectite containing sediment was developed. A new method for obtaining organoclays from enriched smectite clays has been investigated. The method is based on solid-state reaction between smectite and organic compounds, where organic molecules can be intercalated in dried clay mineral (montmorillonite) by solid-state reactions, without or with use of solvents. The enriched clay and the obtained organoclay samples were characterized with X-ray powder diffraction (PXRD).
Time-Gated Raman Spectroscopy for Quantitative Determination of Solid-State Forms of Fluorescent Pharmaceuticals