Rare, precious and specialized metals and alloys are widely used in the defense industry, not only in weaponry and defense equipment, but also for communications equipment and infrastructure. Military contractors require metal products like nickel-aluminum bronze, Beryllium copper and copper-nickel for these and related applications, which include aircraft components, anti-missile defense systems, rockets, explosives detection equipment, missile guidance equipment, communications and satellite systems, and other highly specialized products and equipment.
Copper forms a vital link in the defense industry’s metal and alloy supply chain, carrying a wide range of refined and raw materials with a comprehensive range of applications in the defense industry. The metals uniformly display great strength and durability, the ability to withstand corrosion and temperature extremes, and high levels of wearability. Copper – like nickel and zinc – is a kind of gateway metal, providing access to other elements present in concentrations too minor to mine in their own right. Close the door on copper production, and you’re making a difficult situation far worse for national defense planners tasked with securing reliable supplies of critical metals, according to The 2015 National Defense Stockpile Requirements Report documents.
Copper, which is a d block element, is named as cuprous or cupric based on the electronic configuration. The main difference between cuprous and cupric is that cuprous is copper +1 cation whereas cupric is copper +2 cation. When copper is reacted with oxygen, two stable compounds Cu2O and CuO form. The name “cuprite” of cuprous oxide Cu2O comes from the Latin “cuprum”, meaning copper. Old miners used to call it “ruby copper”. Cuprite mineral has been a major ore of copper and is still mined in many places around the world. Of all the copper ores, except for native copper, cuprite gives the greatest yield of copper per molecule since there is only one oxygen atom to every two copper atoms. As a mineral specimen, cuprite shows fine examples of well-developed cubic crystal
forms. Crystal habits include the cube, octahedron, dodecahedron, and combinations of these forms.
Cuprite’s color is red to a deep red that can appear almost black. Dark crystals show internal reflections of the true deep red inside the almost black crystal. Other varieties, such as chalcotrichite, form long needle-like crystals that have a beautiful red color and a special sparkle that make them popular display cabinet specimens. Cuprite (or cuprous oxide) is the oldest material of semiconductor electronics (Brattain 1951). It has been the subject of numerous theoretical and experimental studies, but still its electronic and atomic structures continue to puzzle the researchers.
New applications of Cu2O in nanoelectronics, spintronics, and photovoltaics are emerging. Compound Cu2O, or cuprous oxide, is a promising material for quantum photonics, optoelectronics and renewable energy technologies. Now, a team of researchers has found a way to synthesize high-quality copper oxide microcrystals.
Differences Between Cuprous Oxide and Copper Nanoparticles
Copper Oxide is the inorganic compound with the formula CuO also known as ‘cupric oxide’. In this form, Cu is in the form of Cu+2 and the electron configuration of the Cu changes from [Ar]3d104s1 to [Ar]3d94s0. It is known as tenorite as a mineral. CuO can be obtained by using pyrometallurgical processes.
Cuprous Oxide is the other stable compound of Copper with formula Cu2O. In this form, Cu is in the form of Cu+1. Its electron configuration changes from [Ar]3d104s1 to [Ar]3d104s0 so it is more stable compared to copper(II) oxide. CuO is generally obtained via the oxidation of copper and it can have yellow or red color. Cu2O degrades to CuO in moist air. This product is a toxic compound and it can cause acute poisoning when exposed to 1-2 hours if it is presented in air at a content of 0.22-14mg/mg3.
In terms of structure, copper oxide has a monoclinic crystal structure where Cu is coordinated by 4 oxygen atoms whereas cuprous oxide has cubic structure where Cu atoms are placed in FCC sublattice and oxygen atoms are placed in BCC sublattice. Solid Cu2O is diamagnetic while CuO exhibits antiferromagnetic ordering. Both are p-type semiconductors, but Cu2O has a band gap of 2eV whereas CuO has a band gap of 1.2 eV – 1.9 eV. Cu2O is obtained by oxidation of copper metal or reduction of copper(II) solutions with sulfur oxide, whereas CuO is obtained by pyrometallurgical processes used to extract copper from ores.
Applications of Copper Oxide (CuO) Nanoparticles are : Many of the wood preservatives are made of copper; It is also used as a pigment to create different glazes and used when welding with copper alloys. Applications of Cuprous Oxide (Cu2O) Nanoparticles include: used as a pigment and antifouling agent form marine paints to kill low-level marine animals. it is used for coating of ship bottom paint.
Cu2O for Solar Cells Applications
Copper oxide (Cu2O) is a very important semiconductor for optoelectronics and photovoltaic applications; it is a promising candidate for technological applications due to its stability, its nontoxicity, and its wide and direct band gap in order of 1.9-2.2 eV . All of these proprieties make Cu2O a promising material in photovoltaic conversion, photocatalysis, and gas sensing. Copper oxide is the most promising p-type semiconductor considered for the manufacture of low cost solar cells . Cu2O thin films can be synthesized by several techniques, including thermal oxidation , electrochemical deposition, chemical vapor deposition, sputtering , Among these techniques, electrodeposition is one of the most practiced thin film deposition methods because of the advantage of simplicity, uniformity on large areas to control the crystallization, morphology and thickness of Cu2O thin films.
High-Quality Copper Oxide Crystals Synthesized for Quantum Photonics
Researchers from KTH Royal Institute of Technology report that they have developed a scalable production method for cuprous oxide (Cu2O) micrometer-size crystals. Also involved in the study were the Institute of Solid State Physics; Graz University of Technology, Austria; and Laboratoire d’Optique Appliquée Ecole Polytechnique, Palaiseau, France. “The unique properties of Cu2O can lead to new schemes for quantum information processing with light in the solid state, which are difficult to realize with other materials,” said Stephan Steinhauer, a researcher in KTH’s Quantum Nano Photonics group. “This work paves the way for the widespread use of Cu2O in optoelectronics and for the development of novel device technologies.”
To synthesize the crystals, a copper thin film is heated to high temperatures in vacuum conditions. In their study, which was published in Communications Materials, the researchers at KTH took this method and identified the growth parameters to achieve Cu2O microcrystals with optical material quality. The process is compatible with standard silicon fabrication techniques and allows the possibility for photonic circuit integration. “The majority of quantum optics experiments with this material have been performed with geological samples found in mines, for instance, the Tsumeb mine in Namibia,” Steinhauer said. “Our synthesis method is associated with very low-cost fabrication, suitable for mass production, and does not require gases or chemicals that are toxic or harmful for the environment.”
Steinhauer said the work lays the foundation for realizing quantum technologies based on solid-state Rydberg excitations, which are excited quantum states with high principal quantum number. According to Steinhauer, these excitations can be interfaced with photonic integrated circuits, aiming at on-chip generation and manipulation of light at the single-photon level. “Exciting challenges lie ahead to translate quantum information processing and quantum sensing schemes previously developed for Rydberg atoms into the solid-state environment of a semiconductor crystal at the micrometer or nanometer scale.”
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