Selective Laser Sintering (SLS) is a highly promising method that plays a crucial role in advancing the development of high-performance and intricate structural materials. Polymer powders are widely recognized for their exceptional strength and versatility as a lightweight structural material. Significant improvements in processing parameters have also expanded the use of SLS polymer parts for structural applications. This research paper thoroughly analyzes the challenges and issues related to SLS from various perspectives. I have a deep understanding of SLS parameters, metallurgical processes, microstructure evolution, metallurgical defects, mechanical properties, and surface roughness. The goal is to create a foundation of knowledge for future research efforts focused on improving productivity in SLS. In addition, the conclusion emphasizes the challenges encountered in research and the possible avenues for future advancements in SLS polymer parts.

Semiconducting nanocomposites (NCs) has proved their dominance in various energy applications. The facile chemical synthesis of semiconducting hybrid NCs of TiO2 nanoparticles with SnSe/SnO2 (SS) nanostructures has been carried out. Structural, morphological, compositions, optical and photo-catalytic (PC) properties of the synthesized materials were then studied by various characterization techniques. The hybrid NC of TiO2 nanoparticles grown with addition of 0.5 g of SS nanostructures has been observed to exhibit the best PC activity among the other samples. The fitted photoluminescence (PL) spectra of pristine TiO2 when compared with the other two TiO2 -SS hybrid NCs showed that the oxygen vacancy (OV) defects play a major role in enhancing the PC property. The samples with superior PC activities have higher intensity of PL emission peak from OVs, efficient charge separation owing to longer lifetime of free charge carriers deduced from time-resolved PL studies and higher surface area.

Marine vessels (MVs), such as cruise ships, submarines, cargo ships, tugboats, and yachts, whether big or small, require powerful batteries to start their engines, to run electric lights, power inverters for kettles, microwaves, induction cookers, and nowadays even air-conditioning systems. Thus, energy-efficient batteries with long life spans have become an integral part of MVs. MVs have various power requirements depending on their size, number of crew members, and mode of operation. Traditionally, lead–acid batteries were used extensively for these purposes but have now been replaced with lithium-ion batteries. Compared with their predecessors, lithium-ion batteries are 60% lighter, nontoxic, have 10 times the cycle life due to a low discharge rate and fast charging, and deliver nearly their rated capacity even at the higher discharge current with no distilled water maintenance. Lithium battery technology based on the lithium–sulfur (Li–S) system has been in the development stage for commercialization because it possesses a higher specific energy density (500 Wh kg−1 or more), is cost-effective, and is more eco-friendly. However, a few issues, such as shuttle reactions and electrode stability, must be addressed to make the commercialization of Li–S battery technology possible. Many companies are now involved in designing and marketing Li–S batteries for automotive, aviation, and marine applications. This chapter is focused on the importance of batteries in marine applications. The energy requirements of different MVs, the types of batteries used and their energy density and capacity, and cost analysis for installation in MVs are summarized. The introduction of developed Li–S technology in electric or hybrid MVs, especially ferries and yachts, can reduce operational costs and greenhouse gas emissions.

In additive manufacturing, selective laser melting (SLM) and electron beam machining (EBM) are two key processes which are widely used for fabrication of Ti6Al4V based products. These fabricated products having outstanding properties are widely employed in automotive, aerospace, marine, biomedical as well as offshore applications. This chapter compares SLM and EBM along with different process parameters, which are involved for processing of Ti6Al4V structures. For deep understanding and to analyze the potential as well as capability of Ti6Al4V structures, their microstructure and mechanical properties are also discussed. Related literature review with key focus is also presented and analyzed. As per these analyses, the challenges and their solutions are presented for improvements.

2D magnetic materials are either monolayer or few layers of 3D van der Waals materials (graphite, MoS2, MoSe2, WSe2, CrI3 etc.) which can be easily cleaved in perpendicular direction by simple and cost-effective exfoliation techniques. This review summarizes the synthesis methods, magnetic properties and transport measurements done on magnetic tunnel junctions, spin valves, multilayer heterostructures made up of 2D magnetic materials. This research area was started in 2017 when intrinsic 2D ferromagnetic ordering was observed in two systems, Cr2Ge2Te3 and CrI3 which was otherwise not possible theoretically as the Mermin–Wagner theorem. As per this theorem, thermal fluctuation will abolish long-range magnetic order in 2D system at finite temperature although 2D Ising type ferromagnetism is possible. Post 2017, there has been extensive research efforts done to explore promising 2D magnetic materials theoretically as well as experimentally as these magnetic 2D layers in vDW heterostructures will open up new possibilities for designing efficient low power- high speed spintronic devices such as magnetic tunnel junctions (MTJs), spin valves, spin filters, spin-FETs, magnetic memory devices and spin torque nano-oscillators.

SnSe-/SnO2-based in situ nanocomposites have been prepared by facile chemical co-precipitation method. These nanocomposites are vacuum-annealed at 400 °C to improve crystallinity. Structural properties of as-deposited and annealed nanocomposites were studied from X-ray diffraction (XRD). Morphological and optical properties are studied by transmission electron microscope (TEM), photoluminescence (PL) and Raman and XPS spectroscopy. The average size of nanoparticles was observed to be in two different ranges: < 10 nm of SnO2 and 30–40 nm of SnSe. PL emission spectra of nanocomposites show strong blue emission (426 nm) and green emission (512 nm) bands which highlight their potential applications in optoelectronics and colour labelling. The photocatalytic activities of the synthesized nanocomposites have been carried out on industrial waste dyes such as methylene blue and rhodamine B. The photodegradation of these dyes under the exposure of sunlight is found to be > 90% in 90 min. The possible mechanism of photodegradation of dyes by nanocomposite has been discussed. The degradation mechanism of rhodamine B dye via rate-limiting stepwise de-ethylation process is suggested. The de-ethylation intermediate products are confirmed by LC-MS measurements.

The growth and deposition mechanism of electrodeposited cobalt nanowires (NWs) at different bath temperatures (25 degrees C-60 degrees C) in strongly acidic bath (pH of 2.0) is studied. CV scans show that hydrogen co-deposition is most pronounced in 50 degrees C bath. X-ray diffraction patterns of Co NWs show that a mixture of hcp and fcc phases grows at 25 degrees C, (200) textured fcc-Co phase grows at 50 degrees C, and (10 (1) over bar0) and (11 (2) over bar0) textured hcp-Co phase at 60 degrees C, with these planes normal to the NW-axis. The magnetic properties studied by vibrating sample magnetometer show the change in coercivity, saturation field and magnetization reversal behavior is consistent with the phase of NW. Nucleation mechanism is explained on the basis of intermediates formation induced by the extent of hydrogen co-deposition leading to the change in nucleation overpotential and linked selection of the growth plane as per bath pH and temperature. Chronoamperometry study has confirmed the instantaneous and progressive growth mechanisms operative at 50 degrees C and 60 degrees C respectively and hydrogen co-deposition controlled grain size growth model is also put forth to understand the growth kinetics of fcc and hcp phase Co NWs. The suggested growth mechanism also consistently explains the growth in less acidic bath of pH 4.5. (C) 2016 The Electrochemical Society. All rights reserved.

This paper reports on the tuning of magnetic behaviour of NiFe alloy nanowires (NWs) by controlling the electro-deposition conditions like bath pH and bath temperature. The increase in temperature of the bath has resulted in the decrease in the grain size of the textured Ni80Fe20 nanowires along with an increase of Fe content in alloy. The magnetic measurements have understandably demonstrated the shape anisotropy in NWs. The observed variation in the coercivity with increase in deposition temperature can be correlated with changes in the alloy composition.

Effect of interdependence of aspect ratio (AR) and c-axis orientation of the hcp-cobalt nanowires (NWs) on their magnetization behavior is reported in 40 and 100 nm diameter NWs. Experimental evidence of periodically modulated magnetic state viz. large transverse-susceptibility arising due to orientation of c-axis normal to NW-axis in 40 nm NWs and magnetic domain imaging is demonstrated, which disappears at low AR owing to randomly oriented c-axes. The 100 nm NWs exhibit a crossover in the easy-axis direction from longitudinal at high AR to transverse at low AR and are explained on the basis of competition between different anisotropic contributions.

Cobalt nanowires (NWs) having hcp crystal structure are structurally tailored for different preferred orientations (PO) of (0002), ( 10 1 ¯ 0 ) , ( 11 2 ¯ 0 ) and ( 10 1 ¯ 1 ) by varying bath temperature and bath concentration in commercially available 50 nm pore diameter polycarbonate (PCT) and 20 nm pore diameter anodic alumina (AAO) membranes. The magnetization studies show orientation dependent competition of magneto-crystalline anisotropy with shape anisotropy. The large effective anisotropy, Keff (along longitudinal direction) of 1.42×106 erg/cc is observed in (0002) PO NWs, which changes sign (−1.50×106 erg/cc) in ( 10 1 ¯ 0 ) PO NWs. The angular dependence of coercivity [HC(θ)] in (0002) oriented Co NWs exhibits a non-monotonic behavior in both the 50 nm and 20 nm samples. The fitting of HC(θ) data reveals that the magnetization reversal mechanism initially takes place by curling and subsequently changes to coherent rotation mode after a certain transition angle, which is higher in case of denser NW array. This increase in transition angle can be attributed to the increased magneto-static interactions in the AAO membrane array having 103 times higher NW areal-density than that in PCT membrane array.

The effect of bath temperature on rotation of c-axis of hcp cobalt vis-a-vis the nanowire axis of 100 am diameter Co nanowires electrodeposited in polycarbonate membranes is studied. While the NWs deposited at 25 degrees C are of the polycrystalline hcp structure, the NWs deposited at 50 degrees C showed preferred orientation (PO) for (10 (1) over bar0) planes along the nanowire axis. In the nanowires deposited at 60 degrees C. the PO changes from (10 (1) over bar0) to (0002) along the nanowire axis. The changes in orientation are associated with the hydrogen co-deposition induced alterations in nucleation and growth mechanism at different temperatures. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.039212jes] All rights reserved.

Controlling the microstructure of nanowires offers a very practical means of producing nanostructures that are amenable to the needs of technological applications. Here we report an interesting observation of structural transition of electrochemically deposited cobalt nanowires with change in aspect ratio of the nanowires. These nanowires were deposited in PCT polycarbonate template single side coated with silver from an optimized CoSO4.7H(2)O bath (50mM) and subsequently their crystal structure were studied using X-Ray Diffraction. At room temperature (303K) change in the aspect ratio (length to diameter) of the nanowires brought in a change in their crystal structure from hexagonal close packing (HCP) to face centered cubic (FCC) as we kept on increasing their aspect ratio by varying the deposition time from 200 to 1000 seconds. Rate of deposition for a fixed bath concentration was studied and using that a critical aspect ratio for the conversion was calculated which came out to be approximately 40. This interesting finding has useful bearing in designing the magnetic behavior and switching characteristics of the wires for device applications.

Nanowires of Ni80Fe20 and Co90Fe10 binary alloys were synthesized by direct current electrodeposition in polycarbonate templates. The purpose of this work is to understand the effect of pH and temperature of the bath on the structural and magnetic properties of these galvanostatically electrodeposited nanowires. The increase in both, pH and temperature of the bath, has resulted in the increase in the grain size of the textured Ni80Fe20 nanowires. The magnetic measurements have understandably demonstrated the shape anisotropy in nanowires. The observed variation in the coercivity with increase in deposition temperature can be correlated with change in the grain size.