More Like this

1. Electrophoretic deposition of iron oxide nanoparticles to achieve thick nickel/iron oxide magnetic nanocomposite films

   https://doi.org/10.1063/1.5129797  

   Mills, Sara_C; Smith, Connor_S; Arnold, David_P; Andrew, Jennifer_S (January 2020, AIP Advances)

   For modern switching power supplies, current bulk magnetic materials, such as ferrites or magnetic metal alloys, cannot provide both low loss and high magnetic saturation to function with both high power density and high efficiency at high frequencies (10-100 MHz). Magnetic nanocomposites comprised of a ferrite and magnetic metal alloy provide the opportunity to achieve these desired magnetic properties, but previously investigated thin-film fabrication techniques have difficulty achieving multi-micrometer film thicknesses which are necessary to provide practical magnetic energy storage and power handling. Here, we present a versatile technique to fabricate thick magnetic nanocomposites via a two-step process, consisting of the electrophoretic deposition of an iron oxide nanoparticle phase into a mold on a substrate, followed by electro-infiltration of a nickel matrix. The deposited films are imaged via scanning electron microscopy and energy dispersive X-ray spectroscopy to identify the presence of iron and nickel, confirming the infiltration of the nickel between the iron oxide nanoparticles. A film thickness of ∼7 μm was measured via stylus profilometry. Further confirmation of successful composite formation is obtained with vibrating sample magnetometry, showing the saturation magnetization value of the composite (473 kA/m) falls between that of the iron oxide nanoparticles (280 kA/m) and the nickel matrix (555 kA/m). These results demonstrate the potential of electrophoretic deposition coupled with electro-infiltration to fabricate magnetic nanocomposite films. 

   more » « less
2. Formation of iron oxide–apatite deposits

   https://doi.org/https://doi.org/10.1038/s43017-022-00335-3  

   Martin Reich, Adam C. (September 2022, Nature reviews)

   Renewed economic interest in iron oxide–apatite (IOA) deposits — containing tens to hundreds of millions of tonnes of Fe and substantial amounts of rare earth elements, P, Co and V — has emerged to supply the sustainable energy transition. However, the mechanisms that efficiently concentrate dense iron- rich minerals (for example, in ores up to ~90% magnetite) at the Earth’s near- surface are widely debated. In this Review, we discuss synergistic combinations of magmatic and hydrothermal iron- enrichment processes that can explain the available geochemical, petrological and geological IOA data. IOA deposits typically evolve from subductionrelated water- rich and chlorine- rich intermediate magmas under a wide temperature range, almost spanning the whole igneous–hydrothermal spectrum (from ~1,000 to 300 °C). Magmatic– hydrothermal fluids could efficiently scavenge Fe from magmas to form large IOA deposits (>100 million tonnes of Fe), whereas crystal fractionation and liquid immiscibility processes might account for more minor Fe mineralization occurrences. Igneous magnetite crystallization, volatile exsolution and highly focused transport of Fe- rich hydrothermal fluids through the crust under extensional tectonic conditions could be key factors enabling concentration of dense magnetite minerals in the less- dense upper crust. Future research should target both fertile and barren mafic–intermediate magmatic suites for distinctive signatures diagnostic of metallogenic fertility, to help unravel the genetic linkage between IOA and iron oxide–copper–gold systems. 

   more » « less
3. Proton‐Mediated and Ir‐Catalyzed Iron/Iron‐Oxide Redox Kinetics for Enhanced Rechargeability and Durability of Solid Oxide Iron–Air Battery

   https://doi.org/10.1002/advs.202203768  

   Tang, Qiming; Morey, Chaitali; Zhang, Yongliang; Xu, Nansheng; Sun, Shichen; Huang, Kevin (August 2022, Advanced Science)

   Abstract Long duration energy storage (LDES) is an economically attractive approach to accelerating clean renewable energy deployment. The newly emerged solid oxide iron–air battery (SOIAB) is intrinsically suited for LDES applications due to its excellent low‐rate performance (high‐capacity with high efficiency) and use of low‐cost and sustainable materials. However, rechargeability and durability of SOIAB are critically limited by the slow kinetics in iron/iron‐oxide redox couples. Here the use of combined proton‐conducting BaZr_0.4Ce_0.4Y_0.1Yb_0.1O₃(BZC4YYb) and reduction‐promoting catalyst Ir to address the kinetic issues, is reported. It is shown that, benefiting from the facilitated H⁺diffusion and boosted FeO_x‐reduction kinetics, the battery operated under 550 °C, 50% Fe‐utilization and 0.2 C, exhibits a discharge specific energy density of 601.9 Wh kg^–1‐Fe with a round‐trip efficiency (RTE) of 82.9% for 250 h of a cycle duration of 2.5 h. Under 500 °C, 50% Fe‐utilization and 0.2 C, the same battery exhibits 520 Wh kg^–1‐Fe discharge energy density with an RTE of 61.8% for 500 h. This level of energy storage performance promises that SOIAB is a strong candidate for LDES applications. 

   more » « less
4. Induced Hyperthermia Using Synthesized Iron Oxide Nanoparticles

   Hernandez, G; Heersema, L; Hufnagel, S; Cui, Z; Smyth, H (January 2018, Biomedical Engineering Society annual meeting)
5. Superionic iron oxide–hydroxide in Earth’s deep mantle

   https://doi.org/10.1038/s41561-021-00696-2  

   Hou, Mingqiang; He, Yu; Jang, Bo Gyu; Sun, Shichuan; Zhuang, Yukai; Deng, Liwei; Tang, Ruilian; Chen, Jiuhua; Ke, Feng; Meng, Yue; et al (March 2021, Nature Geoscience)

   null (Ed.)