Pankaj Kumar

Although oxidation is a primary challenge in the industrial high-temperature sector, the formation of oxidation-resistant surfaces via low-cost routes has been progressing. In this study, partially oxidized alloy powders were developed by a controlled heat-treatment process as a low-cost alternative to conventionally gas-atomized oxide-containing powders. The heat-treated powders of the three nickel-based alloys, AMDRY 962 (NiCrAlY), METCO 15E (NiCrBSiCFe), and PRAXAIR (NiCr), were subjected to cooling under various conditions to produce partial oxidation. Optical and scanning electron microscopies were used to identify the microstructural features of treated powders; these observations indicated a modified surface layer on the treated particles, consistent with partial surface oxidation. X-ray diffraction (XRD) showed treatment-induced changes in the metallic phases but no crystalline oxide, indicating that any surface oxide is thin or amorphous. TIG cladding was performed directly on SS321 stainless-steel substrates with partially oxidized powders deposited without the application of a bond coat. Cyclic oxidation tests were performed at 700 °C for 25 cycles, and the oxidation resistance was evaluated from mass-gain measurements. Under the present test conditions, all coated specimens showed a lower mass gain than the uncoated substrate. The coating layered with METCO 15E exhibited the best oxidation resistance of all layered coatings.

This chapter presents a novel method for generating nickel nanoparticles in deionized water using micro-EDM with polyvinyl alcohol (PVA) for stabilization. Characterization confirmed the excellent stability of the resulting nanofluids with significantly reduced nanoparticle sedimentation. The micro-EDM process itself emerged as a powerful tool for controlling the morphology of the nanoparticles. By decreasing the pulse-on time, researchers were able to precisely manipulate the shape, achieving a transition from spherical to needle-like nickel nanoparticles. Interestingly, this manipulation also resulted in a decrease in both the overall size and the average crystal size of the particles. This ability to tailor multiple properties through a single parameter (pulse-on time) highlights the potential of micro-EDM for the production of well-defined nickel nanoparticles. With PVA effectively preventing agglomeration, this approach opens doors for fabricating nickel nanoparticles with desired characteristics for various applications.

This book provides a comprehensive overview of the latest advancements in unconventional nanoparticle synthesis and their applications, including a foundational understanding of unconventional nanoparticle covering synthesis, characterization, and green manufacturing technologies. Further, it covers laser ablation-mediated synthesis of carbon-coated TiO2 nanoparticles, supercritical CO2-assisted reaction crystallization, continuous hydrothermal nanoparticle synthesis, and safety and environmental implications of unconventional nanoparticle synthesis. Presents insights into both fundamental and applied aspects of unconventional nanoparticle production methods. Discusses progress in unconventional nanoparticle synthesis, particularly in-situ supercritical fluid synthesis with additives. Provide insights into cutting-edge advancements in techniques to produce nanoparticles with distinct properties. Includes an in-depth analysis of green technology to produce nanoparticles. Reviews practical applications of unconventional nanoparticles, highlighting their role in pioneering energy storage solutions. This book is aimed at graduate students and researchers in materials science and nanomaterials.

Polymeric bone implants provide distinct benefits over their metallic counterparts because of their degradability, eliminating the need for surgical removal, especially when placed in complex areas, such as the craniofacial region. This technology is particularly beneficial for pediatric craniofacial fracture treatment. An ideal degradable implant degrades at a pace that matches bone development while maintaining structural integrity. Currently, polylactic acid (PLA) and polylactic-co-glycolic acid (PLGA) are the primary materials used for these implants, although their degradation takes over a year, posing a prolonged biohazard risk to the bone tissue. Thus, this study focused on achieving a faster degradation rate while maintaining the implant strength. The implant, designed using ANSYS SpaceClaim software, was 60 mm long and 2 mm thick, with three 4.5 mm holes. It also includes a centrally located lattice structure to bear any excessive load on the bone and promote suitable bone tissue formation. The mechanical and biomedical properties of the implants were confirmed. The surface roughness was suitable for tissue growth, the hardness managed sudden loads, and the biocompatibility was justified by the degradation rate and potential of hydrogen (pH) observation in in vitro degradation in simulated body fluid (SBF), underlining the advantages of biodegradable materials over traditional alloys, such as 316 L stainless steel, cobalt-chromium alloys, titanium alloys, and nickel–titanium alloys.

This investigation examined the mechanical strength and failure behaviour of various 3D printed lattices for implantation in bones, consisting of octahedral, double pyramid, diamond and cubic lattices. The combination of this research methodology includes a finite element analysis and fatigue testing. Low-cycle compressive fatigue tests were performed using specialized equipment, in addition to the employment of a scanning electron microscope for the properties of the surface and failure modes. The results of this study show that the octahedral lattice provides improved structural performance, a small amount of deformation, uniform stress distribution, and the greatest levels of fatigue resistance. Both diamond and double pyramid lattices indicate moderate deformation and fatigue strength; therefore, they are recommended where flexibility, together with high performance, is a concern. However, the cubic lattice was the worst case, resulting in the highest localized stress and poor ductility. Based on this extensive comparison of identifiers when using fused lattices configured for PLA materials, further studies must introduce physiological stimuli and use versatile biomaterials such as PEEK and titanium. The findings around lattice structure re-emphasize the criticality of lattice choice in the overall improvement of implant outcomes, with the octahedral lattice identified to have impressive fatigue properties that will work well in weight-bearing implants. This study furthers the field of biomedical implant science which could help improve the prognosis of patients through the use of robust bone implants.