Search

Effect of 2 MeV Ni+ion beam irradiation with varying fluences on the surface, structural, and mechanical characteristics of titanium will be explored. For this objective, titanium targets were exposed to nickel ions obtained from a pelletron linear accelerator with 2 MeV energy and various fluences extending from 3 × 1012to 7 × 1015ions/cm2. Penetration features and damage evolution of 2 MeV Ni-ion in titanium have been estimated by employing SRIM-2013 software. Various characterization tools were employed to confirm the modifications in the ion beam irradiated targets. The surface and crystallographic variations of ion beam irradiated targets were explored by employing a scanning electron microscope (SEM) and X-ray diffractometer (XRD). Tensile testing and microhardness analysis was performed by utilizing a software-controlled 50 KN universal tensile testing machine and Vickers’s hardness tester, respectively. The SEM analysis represents random and irregularly distributed sputter morphology for lower ion fluences. With the increase of ion fluence, the pores keep growing radially while the growth rate slows down. At the highest ion fluence, localized melting, evaporation and expulsion of surface material were recorded at the irradiated zone. The X-ray diffraction analysis revealed no additional phases to be developed in the Ni-ion treated titanium. However, a variation in the peak intensity and slight angle/position shifting was reported, which depicts the creation of ion-induced stresses and defects. The mechanical testing results indicated the variations in the mechanical characteristics (yield stress, ultimate tensile stress, hardness etc.) of irradiated titanium. The hardness, yield stress and ultimate tensile strength increased monotonically with the increase of ion fluence. The reported modifications in the mechanical characteristics of irradiated titanium are in good accordance with structural and surface modifications. The stated changes in the irradiated titanium are ascribed to the development of ions induced stress as well to creation, augmentation/expansion, recombination, and annihilation of the ion-induced defects.

AISI M2 high-speed steels are widely used in cutting/forming tools due to their easy machinability and balanced toughness. Unfortunately, they exhibit severe cutting edge wear, which reduces their useful lifetime. The lifetime of such steels can be improved by titanium nitride hard coating. However, in sliding wear applications having a metal-to-metal contact, such coatings exhibit low adhesion to the substrate due to substantial hardness differences among coating and substrate. Here, plasma nitriding is performed before the deposition of magnetron sputtered-TiN coating using various nitriding parameters to find whether the surface properties of the duplex treated sample can be altered by changing these parameters or not. It is found that the surface hardness and hardening depth can be improved by using the duplex treatment as compared to only TiN coating. A significant decrease in wear rate is attained using the duplex treatment and substantial improvement by altering the plasma nitriding parameters.

We irradiate the single crystal boron-doped silicon (Si) at various laser fluences with 100 laser shots in ambient air at room temperature using an Nd:YAG laser and investigate its surface morphology and optical properties. The optical microscopy gives evidence of the formation of a crater and reveals that the heat-affected zone and melted area are increased with increase in laser fluence from 1.1 to 15.4  J/cm^2. The micrographs obtained by scanning electron microscopy (SEM) show that the micro- and nano-structures such as microcracks, bubbles, nucleation sites, clusters, redeposited layered material, nanoparticles, and alike water droplet structures are formed on a laser-exposed Si surface. The optical profilometry of the irradiated Si further confirms the ablation and redeposition of the material and shows that the depth of the crater is increased from 12.1 to 15.2 μm with increase in fluence from 1.1 to 15.4  J/cm^2. Raman spectroscopy of the samples shows that the irradiation generates anneal effects due to higher temperature, which increases the crystallinity of the Si. The ellipsometric analysis shows that the irradiation of Si with increasing laser fluence changes its optical constants (refractive index and extinction coefficient), which further influence its optical properties, e.g., reflectivity, absorptivity, and energy bandgap. The absorptivity of laser irradiated Si tends to increase with increasing laser fluence, and the energy bandgap is decreased accordingly due to increase in structural disorders. Our study shows that the controlled laser irradiation can tune the energy bandgap of exposed Si, and it makes the Si materials useful for the fabrication of optoelectronic devices such as solar cells, photovoltaic cells, and LEDs.

Zn-ion hybrid supercapacitors (ZHSCs) with high power and energy density have great potential in energy storage applications such as hybrid vehicles and renewable energy storage. However, the large radius of hydrated Zn2+-ions hampers their efficient storage in micropores with limited pore sizes, resulting in limited weight ratio capacitance and poor rate capability of ZHSCs. In this study, we developed the novel N-doped and oxygen vacancy-rich CCO nanowires (N-Ov-CCO@CC) architecture with the help of Chemical Vapor Deposition (CVD). Due to the guiding synergy of N-doping, defects, and surface engineering, N-Ov-CCO@CC exhibits significantly enhanced electrochemical performance. The N-Ov-CCO@CC single electrode exhibits excellent charge storage properties, including a high capacitance of 1480.7 F/g at 1 A/g, excellent rate-capability (88.4 % at 20 A/g), and excellent cycle stability of up to 90.1 % for 5000 cycles. The charge storage mechanism was analyzed by ex-situ XRD and XPS, and it reveals that the pseudocapacitive charge storage characteristics are dominant. Operating in the potential range of 1.2–2.0 V, the N-Ov-CCO@CC//Zn-ZHSC provides a high capacitance of 308.2 F/g at 1 A/g, excellent rate capability (86.9 % at 10 A/g), long lifetime (97 % after 10,000 cycles), and high specific energy/power (134.32 Wh/kg at 9507.6 W/kg). Density function theory (DFT) validations show that the N-Ov-CCO system possesses higher conductivities than Ov-CCO and pristine CCO. This work provides an effective strategy for constructing multifunctional electrochemical energy materials for ZHSCs.