Effect of Annealing based on the Structural, Optical, Morphological and Antibacterial Activities of Copper Oxide Thin Films by SILAR Technique

Copper oxide thin films were deposited onto a glass substrate using Successive Ionic Layer Adsorption and Reaction (SILAR) method. The structural, optical, surface morphology, and antibacterial activities are studied. The structural studies revealed that the as-deposited and annealed film at different temperatures like 150 °C, 200 °C, and 250 °C. The preferential orientations of all films are (111) plane with the cubic system. The XRD patterns are well-matched with JCPDS card No: 05-0667. From the UV-vis-NIR studies, the transmittance and absorbance of the film are increased with the increase of annealing temperature. It can attain a maximum temperature of 250 °C. The energy bandgap of the film is calculated using Tauc’s plot. The bandgap of the film is varying from 2.48 eV to 2.19 eV corresponding to the annealing temperature. The antimicrobial assay was tested against Staphylococcus aureus. The zone of inhibition is significantly changed at the temperature of 250 °C (≈16 mm). The surface morphological studies showed that the needle- shaped grains play a crucial role in the antibacterial activity of the Cu2O films. From EDAX, the presence of elements Cu and O in the product was confirmed. Atomic force microscope study depicts that the surface of the film has closely packed nearly uniform-sized grains. From the TEM, the film is well oriented after annealing

Plastic Deformation of Hafnium under Uniaxial Compression

The plastic behavior of polycrystalline hafnium (Hf) was investigated over a range of strain rates under uniaxial compression. Hafnium exhibited considerable ductility and a moderately rate-sensitive plastic behavior. The stress-strain response consisted of initial yielding followed by parabolic hardening. Microstructural observations on quasistatically deformed specimens revealed that yielding occurred by dislocation activity and that hardening was dominated by twinning on {1012} planes and by slip/twin interactions. A considerable reduction in dislocation and twinning activity was observed in specimens deformed at high strain rates. Failure occurred by shear localization and void growth and coalescence within the shear bands. Measurement of the temperature rise during high strain rate deformation was also made. From these measurements, the fraction of work converted to heat as a function of strain was determined and found to decrease with increasing strain