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Copper and its alloys
Published in William Bolton, R.A. Higgins, Materials for Engineers and Technicians, 2020
Copper is extracted almost entirely from ores based on copper pyrites (a mineral in which copper is chemically combined with iron and sulphur). The metallurgy of the process is rather complex, but is essentially as follows: The ore is ‘concentrated’; i.e. it is treated by ‘wet’ processes to remove as much as possible of the earthy waste, or gangue.The concentrate is then heated in a current of air, to burn away much of the sulphur. At the same time, other impurities, such as iron and silicon, oxidise to form a slag which floats on top of the purified molten copper sulphide (called matte).The molten matte is separated from the slag, and treated in a Peirce-Smith converter, the operation of which resembles to some extent that of the furnace used in steel-making by the oxygen process (see Section 11.2). Some of the copper sulphide is oxidised, and the copper oxide thus formed reacts chemically with the remainder of the sulphide, producing crude copper.
Methods of Investigating Structure and Chemical Composition
Published in Rishat G. Valeev, Alexander V. Vakhrushev, Aleksey Yu. Fedotov, Dmitrii I. Petukhov, A. N. Beltiukov, A. L. Trigub, A. V. Severyukhin, Nanostructured Semiconductors in Porous Alumina Matrices, 2019
Rishat G. Valeev, Alexander V. Vakhrushev, Aleksey Yu. Fedotov, Dmitrii I. Petukhov
Copper is introduced into zinc sulfide as the main electroluminescence activator. Copper can react with sulfur and form the inclusions of CuxS phase. At the same time, a lot of heterojunctions of ZnS/CuxS, on which the generation and radiative recombination of charge carriers take place during the electric field excitation, are formed in the phosphor volume. X-ray structural analysis allows detecting and attesting the structure of copper sulfide inclusions. Copper can form point defects of penetration, being the luminescence centers. The emission color depends on penetration type of copper and coactivators. Associates (copper in zinc node)–(copper in interstice) produce the emission of blue color, associates (copper in zinc node)–(chlorine in sulfur node)—the emission of green color.11 Thus, depending on the copper concentration, the predominance of one or another electroluminescence mechanism is possible. Furthermore, it becomes problematic to determine the position of copper atom in the zinc sulfide lattice and its chemical state by the method of X-ray structural state. In this case, it is possible to apply X-ray absorption fine structure (XAFS) methods for investigating the local atomic structure.
Sulfur Carriers
Published in Leslie R. Rudnick, Lubricant Additives, 2017
Thomas Rossrucker, Sandra Horstmann, Achim Fessenbecker
All available sulfur carriers are limited in their thermal stability. This is a desired feature, because reactive sulfur will only be released while the molecule breaks down. However, there are applications running at high temperature where a fast decomposition of the EP product is not desired. Corrosion toward yellow metals is another deficiency of sulfurized compounds. In high-temperature applications, the active sulfur will react with copper to form copper sulfide.
Deposition of stoichiometry – tailored amorphous Cu-S thin films by MOCVD technique
Published in Phase Transitions, 2023
Bolutife Olofinjana, Tobiloba Grace Fabunmi, Frank Ochuko Efe, Oladepo Fasakin, Adebowale Clement Adebisi, Marcus Adebola Eleruja, Olumide Oluwole Akinwunmi, Ezekiel Oladele Bolarinwa Ajayi
Over the years, copper sulphide has gained much interest due to its versatility and potential applications in optoelectronics and solid-state devices such as solar cells, electrochemical sensors, supercapacitors, gas sensors cathode materials in lithium rechargeable batteries, thin film coating for windows filters, among others [1]. This is a result of their tunable semiconductive and metallic characteristics based on their composition [2]. Copper sulphide belongs to a group of chemical compounds with the general molecular formula CuxSy, which can be both synthetic and natural (minerals) materials. Copper sulphide has varieties of stable phase compositions at room temperature among which are, covellite (CuS), anilite (Cu1.75S), digenite (Cu1.8S), djurleite (Cu1.95S), and chalcocite (Cu2S). They have properties in between the most prominent minerals of Cu2S (chalcocite) and CuS (covellite). They are known to have direct band gap energy between 2.4 and 3.8 eV; and absorption coefficients of around 104 cm−1 [3]. The room temperature electrical resistivity is of the order of 10−3–105 Ωm [4,5], which shows the tunable nature of copper sulphide as a result of their stoichiometry. The presence of different phases also has a great influence on electrical properties [6]. The I-V characteristics can be linear showing ohmic behavior [7] in some cases, and diode characteristics in both forward and reverse bias, in others [8].