A precision dimple grinder-polisher produced by 3D printing.

A precision dimple grinder-polisher has been designed and constructed using 3D printing. The purpose of the device is to produce a thin central area in 3 mm round samples for transmission electron microscopy before ion milling to electron transparency. The device can be self-made by any laboratory with a 3D printer for scientific research or teaching, and when combined with recycling and use of biodegradable filaments it can help labs reach their sustainable development goals. A novel sample holder design allows sample alignment without a monocular and thickness detection by light transmission. Novel solutions are developed for aligning the grinding disc and sample rotation motors and for fixing the polishing cloth to the polishing disc. The diameter-depth relationship is investigated for steel and plastic grinding discs. Design principles and materials are discussed, and the tool is evaluated by preparing samples from copper, silicon and tungsten, which are then examined in the transmission electron microscope to evaluate their quality.

A mini vibrational polishing machine produced by 3D printing.

A small vibrational polishing machine (MiniViP) has been designed and constructed almost entirely from 3D printing. The purpose of MiniViP is to produce high quality damage-free surfaces suitable for metallogaphic and electron backscatter diffraction (EBSD) analysis. The experimental device can be self-made by any laboratory with a 3D printer. Combined with use of biodegradable filaments, MiniViP can help research labs reach their sustainable development goals. Design principles and materials are discussed and the device is evaluated by preparing samples from aluminium, brass, copper and nickel and examining the quality of etched surfaces and EBSD grain orientation maps.

A precision core drill for transmission electron microscopy sample preparation produced by 3D printing.

A precision core-drilling machine has been designed and constructed almost entirely from 3D printing. The purpose of the drill is to extract 3 mm diameter discs from thin slices of mainly hard brittle materials for analysis in a transmission electron microscope. Novel methods of producing a slide bearing and shaft couplings in 3D printed components have been developed. Design principles and material selection are discussed, and the drill is evaluated by preparing samples from silicon and aluminium. The device can be self-made by any laboratory with a 3D printer, can be recycled when no longer required and can help labs reach their sustainable development goals.

A precision manual grinding tool for sample preparation.

A novel precision grinding tool has been developed for manual-grinding of samples for analysis in a transmission electron microscope. The tool can be self-made by any scientific laboratory with a 3D printer. Using a simple method, the sample can be precisely aligned with the grinding plane, which enables preparation of samples with highly precise parallel faces. Combined with light weight and low vibration, the device is ideally suited for preparing extremely thin samples even below 10 µm thickness. The paper discusses design principles and materials, and the device is evaluated by preparing samples from magnesium alloy and silicon. Design files are included for 3D printing and CNC milling.

A Facile One-Pot Synthesis of Hierarchically Organized Carbon/TiO2 Monoliths with Ordered Mesopores.

Sol-gel processing combined with soft templating and gelation-induced phase separation is very sensitive to the precursor sol composition. In this work we present a straightforward synthesis towards hierarchically structured, macroporous carbon/titania monoliths with ordered mesopores derived from resorcinol/formaldehyde monoliths and a glycolated titanium precursor. We demonstrate the influence of various reaction solvents, where diol-based media and the proportion of the catalyst seem to be essential in controlling spinodal decomposition, obtaining similar monolithic structures under different synthesis conditions. Based on these observations, we further homogeneously incorporated TiO2 into the carbon structure by an in situ synthesis approach, obtaining structural features similar to pure carbon materials with surface areas of about 400 m2 g-1 , periodically arranged mesopores with a mean distance of 10-11 nm and cellular macroporosity.

Excellent age hardenability with the controllable microstructure of AXW100 magnesium sheet alloy.

Age-hardenability and corresponding improvement of the mechanical properties of Mg-1Al-0.7Ca and Mg-1Al-0.7Ca-0.7Y alloy sheets are addressed with respect to the microstructure and texture evolution during thermomechanical treatments. A fine grain structure and weak texture with the basal pole split into the sheet transverse direction are retained in the Mg-1Al-0.7Ca-0.7Y sheet even after the homogenization at 500 °C, due to the grain boundary pinning by Y-containing precipitates possessing a high thermal stability. Contrarily, the Mg-1Al-0.7Ca sheet shows a coarse microstructure and basal-type texture after the homogenization. The peak-aged condition is attained after the aging at 250 °C for 1800 s of both homogenized sheets, while the Y-containing sheet shows a higher hardness than the Mg-1Al-0.7Ca sheet. TEM analysis and thermodynamic calculation show the formation of metastable precipitates composed of Al, Ca, Y and Mg in the Mg-1Al-0.7Ca-0.7Y sheet at the homogenized and peak-aged conditions. A significant increase in the yield strength is obtained in the peak-aged condition from 162 MPa after the homogenization to 244 MPa, which arises from the increased size and number density of the precipitates. The high age-hardenability of the Mg-1Al-0.7Ca-0.7Y sheet attributes to the superior mechanical properties with an improved ductility promoted by the weak texture.

Novel multifunctional polymethylsilsesquioxane-silk fibroin aerogel hybrids for environmental and thermal insulation applications.

The development of aerogels with improved mechanical properties, to expand their utility in high-performance applications, is still a big challenge. Besides fossil-fuel based polymers that have been extensively utilized as platforms to enhance the mechanical strength of silsesquioxane and silica-based aerogels, using green biopolymers from various sustainable renewable resources are currently drawing significant attention. In this work, we process silk fibroin (SF) proteins, extracted from silkworm cocoons, with organically substituted alkoxysilanes in an entirely aqueous based solution via a successive sol-gel approach, and show for the first time that it is possible to produce homogeneous interpenetrated (IPN) polymethylsilsesquioxane (PMSQ)-SF hybrid aerogel monoliths with significantly improved mechanical properties. Emphasis is given to an improvement of the molecular interaction of the two components (SF biopolymer and PMSQ) using a silane coupling agent and to the design of pore structure. We succeeded in developing a novel class of compressible, light-weight, and hierarchically organized meso-macroporous PMSQ-SF IPN hybrid aerogels by carefully controlling the sol-gel parameters at a molecular level. Typically, these aerogels have a compressive strength (δ max) of up to 14 MPa, together with high flexibility in both compression and bending, compressibility up to 80% strain with very low bulk density (ρ b) of 0.08-0.23 g cm-3. By considering these promising properties, the superhydrophobic/oleophilic PMSQ-SF aerogel hybrids exhibited a high competency for selective absorption of a variety of organic pollutants (absorption capacities ∼500-2600 g g-1 %) from water and acted as a high-performance filter for continuous water/oil separation. Moreover, they have demonstrated impressive thermal insulation performance (λ = 0.032-0.044 W m-1 K-1) with excellent fire retardancy and self-extinguishing capabilities. Therefore, the PMSQ-SF aerogel hybrids would be a new class of open porous material and are expected to further extend the practical applications of this class of porous compounds.