Science Daily February 23, 2023 Often, the progression of localized corrosion is accompanied by the evolution of porosity in materials previously reported to be either three-dimensional or two-dimensional. Using new tools and analysis techniques, a team of researchers in the US (Lawrence Berkeley National Laboratory, Pennsylvania State University, MIT, Pacific Northwest National Laboratory, University of Virginia) realized that a more localized form of corrosion, which they call 1D wormhole corrosion, has previously been miscategorized in some situations. Using electron tomography, they showed multiple examples of 1D and percolating morphology. To understand the origin of this mechanism in a Ni-Cr alloy […]
Tag Archives: Materials science
Designing advanced ‘BTS’ materials for temperature and long-wave infrared sensing
Phys.org February 20, 2023 Replicating the molecular structure and functional motifs of biological compounds often provide clues to advance material designs and offers a blueprint for unprecedented functionalities. An international team of researchers (USA – Caltech, South Korea) has developed a flexible biomimetic thermal sensing (BTS) polymer that was designed to emulate the ion transport dynamics of a plant cell wall component, pectin. Using a simple yet versatile synthetic procedure, they engineered the physicochemical properties of the polymer by inserting elastic fragments in a block copolymer architecture, making it flexible and stretchable. The thermal response of the flexible polymer outperformed […]
Keeping drivers safe with a road that can melt snow, ice on its own
Science Daily February 16, 2023 In this study, a novel and economical green sustained-release microcapsule salt-storage anti-icing agent was prepared by researchers in China using solid waste porous sustained-release skeleton loading organic acetate salt as the core material and styrene-acrylic-acrylate copolymer P(AA-MA-BA-St) as the wall material, which have less corrosiveness and extended the release time. The blast furnace slag and NaHCO3 were selected as the sustained-release skeleton and corrosion inhibitors. The optimal conditions of the synthesis of vesicle wall materials were investigated: 3.8 wt % acrylic acid polymerized at 110 °C with 3 wt % AIBN and for 3.5 h, […]
New corrosion protection that repairs itself
Phys.org February 21, 2023 An international team of researchers (Switzerland, Italy) has developed a plastic, Poly(phenylene methylene) PPM for short, that could greatly improve and simplify corrosion protection. When mixed as paint and heated, PPM can be sprayed onto a surface and becomes solid. The polymer indicates holes and cracks in the protective layer by failing to fluoresce and it repairs any damage itself without further external intervention and has high thermal stability. At the end of a product’s life, the polymer can be completely removed and recycled with only minimal material loss. The recycled polymer can then be applied […]
Can clay capture carbon dioxide?
Phys.org February 9, 2023 Although numerous investigations have studied the formation of H2CO3 in water from CO2, the conversion of CO2 to H2CO3 in nanopores, and how it differs from that in bulk water, has not been understood. Researchers at Sandia National Laboratory used ReaxFF metadynamics molecular simulations to demonstrate striking differences in the free energy of CO2 conversion to H2CO3 in bulk and nanoconfined aqueous environments. They found that nanoconfinement not only reduces the energy barrier but also reverses the reaction from endothermic in bulk water to exothermic in nanoconfined water. Charged intermediates are observed more often under nanoconfinement […]
A counterintuitive way to make stronger alloys
Phys.org February 9, 2023 Low-temperature decomposition of supersaturated solid solution into unfavorable intergranular precipitates is a long-standing bottleneck limiting the practical applications of nanograined aluminum alloys that are prepared by severe plastic deformation. Minimizing the vacancy concentration is generally regarded as an effective approach in suppressing the decomposition process. An international team of researchers (China, Norway, Italy) has developed a strategy to stabilize supersaturated solid solution in nanograined Al-Cu alloys via high-density vacancies in combination with Sc microalloying. By generating a two orders of magnitude higher concentration of vacancies bonded in strong (Cu, Sc, vacancy)-rich atomic complexes, a high thermal […]
Scientists open new window on the physics of glass formation
Phys.org January 24, 2023 A common feature of glasses is the “boson peak”, observed as an excess in the heat capacity over the crystal or as an additional peak in the terahertz vibrational spectrum. The microscopic origins of this peak are not well understood; the emergence of locally ordered structures has been put forward as a possible candidate. An international team of researchers (UK, Slovenia, Japan) has shown that depolarised Raman scattering in liquids consisting of highly symmetric molecules can be used to isolate the boson peak, allowing its detailed observation from the liquid into the glass. The boson peak […]
MIT engineers grow “perfect” atom-thin materials on industrial silicon wafers
MIT News January 18, 2023 Two-dimensional materials and their heterostructures show a promising path for next-generation electronics. Nevertheless, 2D-based electronics have not been commercialized, owing mainly to three critical challenges: i) precise kinetic control of layer-by-layer 2D material growth, ii) maintaining a single domain during the growth, and iii) wafer-scale controllability of layer numbers and crystallinity. An international team of researchers (USA – MIT, UT Dallas, UC Riverside, Washington University, South Korea) has introduced a deterministic, confined-growth technique that can tackle these three issues simultaneously, thus obtaining wafer-scale single-domain 2D monolayer arrays and their heterostructures on arbitrary substrates. They geometrically confined the […]
Solid material that ‘upconverts’ visible light photons to UV light photons could change how we utilize sunlight
Phys.org January 30, 2023 Only about 4% of terrestrial sunlight falls within the UV range in the electromagnetic spectrum. This leaves a large portion of sunlight spectrum unexploited for photopolymerization to form a resin and activation of photocatalysts to drive reactions that generate green hydrogen or useful hydrocarbons (fuels, sugars, olefins, etc.). Photon upconversion (UC) could be the key to solving this problem. Researchers in Japan have developed a revolutionary solid film that can perform visible-to-UV photon UC for weak incident light while remaining photostable for an unprecedented amount of time in air. The film is completely solvent-free “green” formation […]
Solids that are also liquids: Elastic tensors of superionic material
Phys.org January 30, 2023 Superionics display both solid- and liquid-like characteristics: as solids, they respond elastically to shear stress; as liquids, they display fast-ion diffusion at normal conditions. They are technologically relevant for energy, electronics, and sensing applications. Characterizing and understanding their elastic properties are needed to address their feasibility as solid-state electrolytes in all-solid-state batteries. However, static approaches to elasticity assume well-defined reference positions around which atoms vibrate, in contrast with the quasi-liquid motion of the mobile ions in fast ionic conductors. Researchers in Switzerland have derived the elastic tensors of superionics from ensemble fluctuations in the isobaric-isothermal ensemble, exploiting extensive Car-Parrinello simulations. They applied this approach to […]