G. Alan Castillo

Chemically deposited Sb2S3 thin films for optical recording

Laser induced changes in the properties of Sb2S3 thin films prepared by chemical bath deposition are described in this paper. Sb2S3 thin films of thickness 550 nm were deposited from a solution containing SbCl3 and Na2S2O3 at 27 °C for 5 h. These thin films were irradiated by a 532 nm continuous wave laser beam under different conditions at ambient atmosphere. X-ray diffraction analysis showed amorphous to polycrystalline transformation due to laser exposure of these thin films. Morphology and composition of these films were described. Optical properties of these films before and after laser irradiation were analysed. The optical band gap of the material was decreased due to laser induced crystallization. The results obtained confirm that there is further scope for developing this material as an optical recording media.

Corrosion Mechanisms in Refractory Castables by Liquid Oxides

Corrosion in refractories in a commercial furnace is a very complex phenomenon which involves chemical and physical wear. In this work three refractory castables (A, B and C) are being characterized and studied to compare their properties and determine their corrosion mechanisms in the presence of slag obtained from a steel furnace. The chemical composition of the slag consists mainly of CaO, SiO2, alumina and Fe2O3. Using a heating microscope, it was determined that the slag starts to melt around 1350 oC. The chemical composition of the castables consist mainly of alumina (86%, 90% and 92% respectively) with a variation in material A which contains 5.8% MgO. Prismatic bars were made and sintered at 1400 C to run the hot modulus of rupture at 1000 C. A non-destructive technique was used to investigate the Young’s modulus of the specimens before and after sintering.