Soltabayev, B.; Er, I Karaduman; Surel, H.; Coşkun, A.; Yildirim, M.A.; Ateş, A.; Acar, S.

Zn1-xNixO thin films (x = 0, 0.05, 0.10, 0.15 and 0.20) were systematically synthesized by Successive Ionic Layer Adsorption And Reaction (SILAR) method with 40 SILAR cycle and then were annealed at 300 °C. Influence of nickel doping and annealing treatment on the structural, morphological, optical and gas sensing properties of Zn1-xNixO thin films were investigated. X-ray diffraction (XRD), scanning electron microscope (SEM) and optical absorption measurements were used for characterization of the films. The gas sensing properties of the Zn1-xNixO sensors for low nitric oxide (NO) gas concentrations were investigated as a function of operating temperature and doping concentration. The gas sensing results showed that the doping process strongly influenced the response of ZnO sensors. The optimal operating temperature of the sensors was found of 95 °C, the response of the annealed Zn00.90Ni0.10O sensor for 25 ppm NO reached a maximum of 63%. The Zn0.90Ni0.10O sensor exhibited higher response and better response/recovery times than the others. It was concluded that Ni doping and annealing treatment enhanced the gas sensing properties of sensors by changing microstructure, morphology, bandgap of ZnO films.

Comakli, O.; Yetim, A.F.; Karaca, B.; Celik, A.

Grey cast iron is commonly utilized as an engineering material owing to its some properties such as its good machinability, ability to dampen vibrations, low-stress concentration, high thermal conductivity, good castability and low cost. Especially when this material is used as camshaft material, it can be exposed to wear because of its low wear properties. So, various surface treatment is applied to improve tribological properties of the grey cast iron. In this study, the grey cast irons were plasma nitrided under different gas mixture ratios for this aim. The structural, morphological and mechanical properties of plasma nitrided grey cast iron specimens were investigated by XRD, SEM, EDS and microhardness test. Also, tribological properties of unnitrided and nitrided specimens were characterized by tribotester under dry and lubricated conditions.