The media advertizes that soon everybody can manufacture models and parts of all kinds via computer-aided design –computer-aided manufacturing by additive manufacturing (AM) technologies. That can boost the do-it-yourself activities enormously. But it can also revolutionize the industries: Most conventional technologies of manufacture are profitable only in big lots of production. For single specimens and small lots of production, they are too expensive. But with AM, one or a few original or spare parts can be produced at low cost. However, to succeed in the market, the AM products must become competitive. They must have reproducibility of an exact shape, even in tiny details, a perfect surface and, above all, sufficient mechanical strength. This article deals with three-dimensional ink-jet printing with monomer inks and polymer powders. Since powder beds are always porous, the main aim was to fill the pores permanently with high amounts of the ink polymer. A new polymer powder that rapidly dissolves in monomer inks is reported.

Transparent 0.67(Pb1−xLax)(Mg1/3Nb2/3)O3–0.33(Pb1−xLax)TiO3 (x = 0–0.05) ceramics were successfully prepared without using a hot-pressing technique. The optical transmittance at the wave length of 400–2000 nm increased with increasing lanthanum (La) content, x from 0 to 0.03. The transmittance at 600–2000 nm further increased (with the highest transmittance of 68% at 2000 nm for ceramics with thickness of 0.5 mm) at x = 0.04 and 0.05, while the transmittance at 400–600 nm decreased. X-ray diffraction patterns suggested that the overall increase in the transmittance with x was associated with a change in the crystal systems from a monoclinic phase to a pseudocubic phase, and the decrease at x = 0.04 and 0.05 was related to the formation of an impurity second phase. Their microstructures and dielectric properties were also studied.

Three-dimensional transmission electron microscopy (3D-TEM) is a powerful technology that provides 3D characterization of the internal details of a material. In this work, for the first time, 3D-TEM was used to characterize a laser-sintered polymer nanocomposite. The dispersion of carbon nanotubes (CNTs) in the laser-sintered polyamide 12 (PA12)-CNT nanocomposite parts was evaluated. At first, to prepare 3D-TEM samples at specific locations, a focused ion beam technique was used. Then, high quality two-dimensional (2D)-TEM images were achieved at various scanning angles for the PA12-CNT laser-sintered sample. After that, 3D-TEM images were reconstructed by combining all the 2D-TEM images. Results revealed that the CNTs were agglomerate-free in the PA12-CNT parts after laser sintering, which helps to explain previously reported improvement in mechanical properties of laser-sintered PA12-CNT parts.

Graphene is currently one of the most extensively studied materials because it displays a number of unique structural and electronic properties. A variety of methods are currently available for the growth of graphene; however, few are viable for large scale, cost-effective production of high quality graphene. Here, a novel growth process for few layer graphene using chemical vapor deposition (CVD) and a commercial iron nanopowder catalyst is described. This method is readily scalable so it can be used to produce a large volume of graphene sheets. Graphene sheets made from this process were characterized by Raman spectroscopy, and scanning and transmission electron microscopy. Raman spectroscopy shows that the product consists of few layer graphene sheets. This is the first reported method of utilizing nanoparticles to synthesize graphene by a CVD process, which typically produces multiwalled carbon nanotubes. A possible mechanism for the formation of graphene by this modified CVD process is discussed.

This work describes the use of a piezo-actuated inkjet print head with a nozzle aperture of 50 µm to obtain picoliter drops of different model ionic liquids (ILs). A theoretical analysis of the microdrop generation of three model ILs is confirmed by experiments. The inkjet print process was optimized to enable a stable and reproducible drop ejection in both continuous and drop-on-demand modes by controlling the temperature of the nozzle, as well as the electrical signal sent to the piezo actuator used to generate the drops. Controlled volumes ranging from 43 ± 3 pL to 319 ± 1 pL have been achieved, with a volume control down to 3 pL. The null volatility of ILs yields an extremely high stability of the inkjet process, obtaining drops with very constant volumes during the entire print process. It also avoids the coffee staining effect observed in the deposition of conventional liquid drops. The possibility to deposit controlled volumes in a reproducible way is demonstrated here and applied to a proof-of-concept application with the aim to create dense concave optical lens arrays by replicating the deposited ionic liquid microdrops in poly(dimethylsiloxane) (PDMS).

CoCrMo alloy was deposited on a metallic substrate using laser engineered net shaping (LENS™) – a laser-based additive manufacturing technique. Several samples with five layers of deposit were fabricated at different combinations of laser power, powder feed rate, and scan velocity to study their influence using L4 Orthogonal array. The deposits were evaluated for their microstructure, hardness, wear resistance, and electrochemical performance. Grey relational grade analysis and analysis of variance were applied to identify optimum process parameters. The x-ray diffraction and microstructural analysis of the deposits showed uniform and fine microstructural features. Our experimental results revealed that the coatings fabricated using high laser power (350 W), low powder feed rate (5 g/min), and high scan velocity (20 mm/s) provide the highest hardness (446 ± 2.87 Hv) and wear resistance (1.80 ± 0.0007 mm3/Nm). However, the corrosion resistance was observed to be high for the deposits fabricated using low laser power (200 W), low powder feed rate (5 g/min), and low scan velocity (10 mm/s).

Spherical and conical nanoindentation experiments were performed for the same polymer specimens to compare Young's moduli measured from the elastic loading and unloading curves, and bending experiments. Finite-element simulation was employed to ensure pure elastic deformation during spherical nanoindentation. The moduli measured from the elastic loading curves using Hertz's contact law are very close to the bending moduli, because both measurements were conducted under the same elastic deformation. However, the moduli measured from the elastic unloading curves are up to 60% higher than the bending moduli owing to plastic deformation close to the sharp conical indenter tip.

A number of recent mechanical property studies have sought to validate atomistic and multiscale models with matching experimental volumes. One such property is the ductile–brittle transition temperature (DBTT). Currently no model exists that incorporates both external and internal variables in an analytical model to address both length scales and environment. Using thermally activated parameters for dislocation plasticity, the present study attempts a small piece of this. With activation energy and activation volumes previously determined for single and polycrystalline Fe–3% Si, predictions of DBTT both with and without atmospheric hydrogen are made. These are compared with standard fracture toughness measurements similarly for samples both with and without atmospheric hydrogen. In the hydrogen-free samples, average strain rate varied by four orders of magnitude. DBTT shifts are experimentally found and predicted to increase 100 K or more with either increasing strain rate or exposure to hydrogen.

Adsorbents with high specific surface areas, developed porosities, and sustainable CO2 capture capacity (∼180 mg/g at 25 °C, 1 bar) were prepared by KOH activation of hydrothermally carbonized carboxymethylcellulose (CMC). Condensed aromatic carbon materials (CSc) with particle diameters of 2–3 μm and many oxygen-containing groups on their surfaces can be obtained after hydrothermal treatment of CMC; these materials are similar to glucose-derived hydrothermal carbons. The activation conditions, including activation ratio and activation temperature, significantly influence the structure and morphology of the adsorbents. In turn, the pore structures, specific surface areas, and adsorption conditions significantly affect the adsorption capacities of these new adsorbents. For samples with the same activation ratio, those with higher specific surface areas show higher CO2 capture capacities at 25 °C and 1 bar. Under these conditions, for samples with different activation ratios, the capacity is dominated by the microporosity development and, in particular, the high volume of smaller micropores (d = 0.4–0.9 nm); when the adsorption pressure is decreased to 0.1 bar, the CO2 capture ability becomes closely correlated with the number of ultramicropores (d < 0.7 nm).