The kinetics of formation of calcium aluminates was studied by firing the reaction mixes in the temperature range 1200" to 1460°C for reaction times from 15 to 360 min. Phases formed were determined by taking X-ray diffractograms of the samples. It was observed that all stable calcium aluminates were formed and that monocalcium aluminate (CA) grew with calcium dialuminate (CA,) in a 1:2 reaction mix of CaO and A1203. CA reacted further with AIz03 to form CA,. The formation of CA, obeyed the rate law equation 1 -(1 -x)ln = Kt/rZ. The activation energy for the system (140 kJ-mol-' (33.4 kcal-mol-')) was determined by the Arrhenius equation. [

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Aluminium doped zinc oxide (AZO) thin films were prepared on glass substrate by spray pyrolysis technique and subsequently their structural, morphological and optical properties were investigated and analyzed as a function of annealing temperature. The films were deposited at 350°C and were annealed at temperature 350, 400, 450 and 500°C. X-ray diffraction (XRD) analysis confirms that both deposited and annealed films are polycrystalline in nature and have hexagonal wurtzite structure. The crystalline size as well as the crystalline quality of the film was found to increase with the increase of annealing temperature to a certain point. However, the dislocation density and the compressive stress induced in as-deposited AZO films reduce with annealing temperature. SEM image reveals that the deposited film has nanorope like morphology. The average diameter of the rope and the density of the morphology increases with the increase of annealing temperature. As the annealing temperature increases from 350°C to 450°C, the average transmittance of the films increases and the band gap value decreases from 3.25 eV to 3.17 eV. In addition, obtained results also show that urbach energy, extinction coefficient, refractive index, optical conductivity has changes noticeably with annealing temperature.