Phys.org July 8, 2019 An international team of researchers (Germany, Russia, Sweden, USA – University of Chicago, France) has developed a route to scale up the synthesis of rhenium nitride pernitride through a reaction between rhenium and ammonium azide, in a large-volume press at 33 GPa. Although metallic bonding is typically seen incompatible with intrinsic hardness, Re2(N2)(N)2 turned to be at a threshold for super hard materials. The process can be used for the synthesis of other nitrides, in particular nitrides of transition metals, which could also have technologically important properties…read more. Open Access TECHNICAL ARTICLE
Category Archives: Advanced materials
Found: A sweet way to make everyday things almost indestructible
Science Daily June 27, 2019 An international team of researchers (USA – University of Virginia, University of Washington, Brookhaven National Laboratory, industry, University of Minnesota, USAID, UT Austin, Colorado State University, the Netherlands, France, UK, Tanzania, Switzerland, Italy) found that organisms that live in harsh environments have a pili on the surface. Pili, which are protein filaments, normally would be very sensitive to heat, acid and enzymes, but coating it in sugars make it almost indestructible. The sugars were arranged in such a stable fashion that even acid can’t dissolve them. According to the team coating materials with the special […]
Superhydrophobic ‘nanoflower’ for biomedical applications
Science Daily July 2, 2019 Current superhydrophobic materials require alteration to the chemistry or topography of the surface to work which limits their use. Researchers at Texas A&M adopted a ‘nanoflower-like’ assembly of Molybdenum disulfide (MoS2) atomic layers to protect the surface from wetting. With their hexagonal packed layer 2D materials repel water adherence, however, a missing atom from the top layer can allow easy access to water molecules by the next layer of atoms underneath making it transit from hydrophobic to hydrophilic. For biomedical applications specifically, the study demonstrated that blood and cell culture media containing proteins do not […]
Graphene and nanotube mesh filters salt from water
Physics World June 24, 2019 Porous graphene sheets have excellent filtration capabilities and can block most ions, but their fragility limits their scale-up beyond laboratory demonstrations. An international team of researchers (China, USA – UCLA) has developed a way to create centimetre-sized sheets of porous graphene that do not suffer from the effects of defects. This was done by depositing a mesh-like network of single-walled carbon nanotubes on top of a graphene sheet, which essentially reinforces the material and blocks the spread of cracks and tears. Then the pores are etched in the material to create a desalination membrane. When […]
A new ‘golden’ age for electronics?
Science Daily June 25, 2019 One way that heat damages electronic equipment is by making components expand at different rates, resulting in forces that cause micro-cracking and distortion. The valence fluctuations of Sm in samarium monosulfide (SmS) are known to induce possible large isotropic negative thermal expansion (NTE). Researchers in Japan prepared Ce-doped and Nd-doped SmS polycrystalline samples using a simpler method with much lower reaction temperature than the existing method. Typically, Sm0.80Ce0.20S exhibits giant NTE with total volume change of 2.6% in the wide temperature range from 330 K to 100 K, the lowest covered here. This research opens a new […]
Materials informatics reveals new class of super-hard alloys
Phys.org June 13, 2019 Researchers at Lehigh University used materials informatics to predict a class of materials that has superior mechanical properties. Using experimental tools, such as electron microscopy to gain insight into the physical mechanisms led to the observed behavior in the high-entropy alloys. They found alloys that had hardness values that exceeded by a factor of 2 better than other, more typical high-entropy alloys and other relatively hard binary alloys. Some exhibited new structures and superior mechanical properties, as well as enhanced oxidation resistance and magnetic properties, relative to conventional alloys. Such materials could potentially withstand severe impact […]
Metal foam stops .50 caliber rounds as well as steel – at less than half the weight
Phys.org June 5, 2019 A team of researchers in the US (North Carolina State university, U.S. Army) investigated the effectiveness of the Composite Meta Foam (CMF) hard armor armor system consisting of a ceramic faceplate, a CMF core and a thin back plate made of aluminum. The armor was tested using .50 caliber ball and armor-piercing round with the rounds being fired at impact velocities from 500 meters per second up to 885 meters per second. The CMF layer was able to absorb 72-75% of the kinetic energy of the ball rounds, and 68-78% of the kinetic energy of the […]
Researchers ‘stretch’ the ability of 2-D materials to change technology
Phys.org June 10, 2019 An international team of researchers (USA – University of Rochester, China) developed a platform and deposited a flake of molybdenum ditelluride (MoTe2) onto a ferroelectric material. When voltage is applied to the ferroelectric—which acts like a transistor’s third terminal, the 2-D material by the piezoelectric effect, causing it to stretch. When stretched, by about 0.4 percent, and unstretched, the MoTe2 changes from a low conductivity semiconductor material to a highly conductive semi metallic material and back again. It operates just like a field effect transistor. The process works at room temperature and requires only a small […]
‘Metasurfaces’ that manipulate light at tiny scales could find uses in consumer technology
Phys.org May 22, 2019 Metasurfaces etched with individual features can create patterns that enable the surface to scatter light very precisely if the exact pattern needed to produce a desired optical effect is known. A team of researchers in the US (MIT, Harvard) has developed a computational technique that can quickly map out patterns for a range of desired optical effects. Instead of having to solve Maxwell’s equations for every single nanometer-sized pixel in a square centimeter of material, the researchers solved these equations for pixel “patches.” Using their technique, the researchers quickly came up with optical patterns for several […]
Scientists create new aluminum alloy with flexibility, strength, lightness
Phys.org May 27, 2019 At present aluminum is reinforced mainly with the help of nanopowders, but this is an extremely expensive and time-consuming process. Researchers in Russia have demonstrated that if a melting technique is used, after Al-Ni-La crystallization, the diameter of doping particle does not exceed 30-70 nanometers. Due to natural crystallization, particles are distributed uniformly, forming a reinforcing structure. Hence, the composite becomes stronger and more flexible than its powder analogues. The important feature of the new development is the high reinforcing ability of the chemical compounds with ultrafine structure: the diameter of the reinforcing elements does not […]