P. Kuppusami

Microstructural, nanomechanical and antibacterial properties of magnetron sputtered nanocomposite thin films of CrN/Cu

Abstract Synthesis of nanocomposite thin films of CrN/Cu on (100) Si and titanium modified stainless steel (D-9 alloy) substrates by pulsed magnetron sputtering from a composite target of Cr–Cu using sputtering gas mixture of argon and nitrogen is investigated. X-ray diffraction analysis of the films deposited at 773 K and 10 sccm of nitrogen flowrate indicated that the films are nanocrystalline and biphasic (fcc CrN and fcc Cu). The films showed a peak hardness of ∼15 GPa and a Young’s modulus of ∼200 GPa for those with a copper content of 15·1 at-%, and these values were found to decrease significantly with a Cu content of ⩾18·4 at-%. The evaluation of the antibacterial activity as a function of copper content in the range of 15·1–38·5 at-% indicated excellent antibacterial properties for CrN/Cu films with the copper content of 18·4 at-%. The phase stability of CrN of the nanocomposite is also discussed in relation to pure CrN thin films.

Structural and optical properties of electron beam evaporated yttria stabilized zirconia thin films

Yttria stabilized zirconia (10 mole % Y2O3) thin films were deposited on quartz substrates using electron beam physical vapor deposition at the substrate temperatures in the range 300 – 973 K. XRD analysis showed cubic crystalline phase of YSZ films with preferred orientation along (111). The surface roughness was found to increase with the increase of deposition temperatures. The optical band gap of ∼5.7 eV was calculated from transmittance curves. The variation in the optical properties is correlated with the changes in the microstructural features of the films prepared as a function of substrate temperature.

X‐Ray Diffraction Analysis of Defects in Cold Worked Type 316 Stainless Steel

In the present study, the dislocation densities of the cold worked type 316 stainless steel were calculated on the basis of the crystallite size and strain present in the samples using Williamson–Smallman approach. The samples annealed at 1323 K, 30 minutes and then furnace cooled were cold rolled to various percentages in the range 5–40percent;. Dislocation density has been found to increase with increasing percentage of cold work. The dislocation density values were correlated with hardness values of the cold worked samples.