Copper Inclusions Research Articles

Effects of copper on hydroxyapatite thin films by pulsed laser deposition on silicon

AbstractThis study deals with the effect of Cu on hydroxyapatite (HAp) thin films on silicon substrates prepared by pulsed laser deposition (PLD) technique for Cu concentrations ranging from 0 to 0.8 wt.%. Fourier transform infrared spectroscopy and Raman spectroscopy provide additional evidence of HAp in the films, which exhibit characteristic HAp bands such as the 960 cm−1 phosphate ion band. The X‐ray diffraction patterns confirm the presence of HAp, without copper‐related peaks, suggesting that it is not incorporated into the HAp lattice, which is present as an amorphous phase. X‐ray photoelectron spectroscopy confirms the presence of Cu on the HAp thin films, possibly related to the adsorption of Cu2+ on HAp surfaces through electrostatic or interactions with (PO4)3− groups. Atomic force microscopy shows that the roughness of the films varies depending on the presence or absence of copper ions. Finally, density functional theory and kinetic Monte Carlo simulations explain the effects of atomic diffusion on roughness and HAp clustering. These changes correlate with the contact angle values, indicating the formation of hydrophobic films due to copper inclusions.

Preparation of copper glycinate and study of its effect on the germination of winter barley seeds

We analyzed the encrustation of winter barley seeds, which includes its preliminary treatment with cuprum glycinate, with the purpose of increasing yield and biochemical indicators of grain, and also improving the ecological condition of the soil. The objective of the research was to select methods for the synthesis of cuprum glycinate, study its chemical composition and the possibility of using this compound as a chelated micro-fertilizer for pre-sowing encrustation of winter barley seed as part of a tank mixture. Two well-known synthesis methods were used to obtain cuprum glycinate. The first method was the interaction between CuO with a solution of glycine during heating, during which pink metallic copper inclusions were noticed in the mixture of reaction products. It was found that it is expedient to synthesize the glycine complex of cuprum by the reaction of a suspension of Cu2CO3(OH)2 with glycine during heating (the yield is 97%), since a complex compound Cu(NH2CH2COO)2•H2O of sufficient purity is formed. The composition of the synthesized substance and the confirmation of the formula of the compound Cu(NH2CH2COO)2•H2O were obtained by determining the infrared and the atomic absorption spectrum of the aqueous solution. Based on the obtained differences in the atomic absorption spectra of the synthesized copper sulfate and copper glycinate the formation of the latter was confirmed. The IR spectrum confirms the formula of the complex compound and the formation of strong covalent bonds between the metal cation and the ligands. The study of the effect of cuprum glycinate on the germination of winter barley Tutankhamun seeds was carried out in comparison with the similar effect of a complex compound of cuprum with ethylenediaminetetraacetate. The study of the influence of cuprum glycinate on the germination of winter barley revealed positive results in which the germination exceeded the control by 9–27%. Winter barley seeds treated with distilled water served as a control. Treatment of winter barley seeds with an aqueous solution of cuprum glycinate in the amount of 20 g of cuprum per 1 ton of grain led to better germination than pre-treatment of seeds with a twice concentrated corresponding solution. Treatment with a complex compound of copper with ethylenediaminetetraacetate had no significant effect on the germination and characteristics of sprouts. The results of laboratory studies confirmed the feasibility of using complex compounds of biometal copper with organic chelating ligands as microfertilizers for pre-sowing seed encrustation, as they have high stability and sufficient solubility in water, are non-toxic, are better absorbed by plants and are considered cost-effective and environmentally safe.

Charakteristika měděného slitku ze zlatého dolu na Zlatém vrchu v Mníšku pod Brdy (střední Čechy, Česká republika)

A copper pig with dimensions 3.3 × 2.3 × 1.7 cm and weighing 25 g was found together with few iron artefacts (several mining chisels, several fragments of mining hoes, a hook) in dump material of ancient gold mine at the Zlatý vrch Hill near Mníšek pod Brdy town, central Bohemia, Czech Republic. The gold mines were in operation in the surrounding area in the 15-16th centuries with some later attempts in 18th century. A material characterization of the copper artefact, based on reflected light microscopy and electron microprobe study, is presented in this paper. The composition can be roughly approximated as an As-poor Cu-As alloy, with predominating matrix composed of low-As copper and most impurities being concentrated in intergranular spaces of low-As copper grains, where domeykite and inclusions of native lead were identified. The copper matrix contains 1.54 - 2.23 wt. % As, and low Sb and Ni. Strongly substituted domeykite (Cu3As) contains high Sb (9.3 - 15.6 wt. %) and lesser amounts of Pb, Ni, S, Ag, Sn, and Fe. Metallic lead is characterized by elevated contents of Bi, Ag, Sb, Cl, and S. In addition, a discontinuous rim with composition close to cuprite (Cu2O), locally containing inclusions of a Sb-As oxide, was identified on the surface of the copper pig. The element assemblage observed in the studied metallic artefact may indicate the source of the copper ore in the neighbouring base-metal (Ag-Pb-Zn) Příbram ore area, however, there are not known indications of historical smelting of sporadically occurring copper ores in the Příbram area. Therefore, we suggest that the studied artefact likely has more distal provenance.

First evidence for alloying practices in the Chalcolithic Southern Levant (4500–3800 BCE) as revealed by metallography

Excavations at the Chalcolithic site Fazael in the central Jordan Valley uncovered a large number of metal items, many of them polymetallic copper alloys cast in the lost wax technique. Metallography and SEM–EDS analysis on a subset of the assemblage confirm previous notions of the lost wax metallurgy in the Chalcolithic Southern Levant but extend them significantly in three aspects: The Fazael metal assemblage is slightly depleted in its arsenic content compared to metal assemblages from other sites, silt-sized quartz inclusions in unalloyed and polymetallic copper items, and the presence of unalloyed copper inclusions. These latter provide the earliest direct evidence for mixing of different metal types in West Asia, potentially alloying or recycling.

Metal prills in primary glass: A puzzling aspect of the production process

Primary glassmaking in the first millennium CE during Roman and post Roman periods was conducted in large heating installations, the so-called tank furnaces, in two main regions of the East Mediterranean, namely the Levant and Egypt. Especially in Israel, a large number of tank furnaces in various sites such as Apollonia, Bet Eli’ezer (Hadera) and Jalame have been discovered, giving new insights regarding the technology of glassmaking in the first millennium CE.In this paper, we investigate the existence of metal prills embedded in raw glass at the contact layer with a tank furnace floor. The glass chunks were found in a refuse pit at Umm ez-Zinat, southern Carmel, Israel, and are dated to the Late Roman-Early Byzantine periods (fourth-early fifth centuries CE) based on glass vessels found with the debris of primary and secondary production. Another three prills from Bet Eli’ezer, the massive glass industry dated to the seventh-early-eighth centuries CE, were also analysed to compare any similarities/differences between the prills from the two sites.Results show that the prills vary greatly in shape and composition. Their morphology ranges from rounded spheres to asymmetric ellipses, all showing inclusions indicating the source material was chemically heterogeneous. The prills from Umm ez-Zinat are mainly lead, with minor contribution of copper, tin, antimony and silver as inclusions. Two of the three prills from Bet Eli’ezer are copper alloyed with lead, and one has a lead matrix with various copper inclusions. We investigate possible scenarios to understand the nature of the metal in the glass, how and when it was added to the glass melt, and possible technological and ritual interpretations for its presence.

Further Characterisation of Native Copper Inclusions in Cu-Bearing Tourmaline

Further Characterisation of Native Copper Inclusions in Cu-Bearing Tourmaline

Microstructure and mechanical properties of a welded joint obtained by friction stir welding of thin copper and aluminum plates

Friction stir welding was used to produce a welded joint of 1 mm thick plates of copper M1 and aluminum alloy AMg2M. The microstructure of the shoulder-side of the joint had areas of mixing of aluminum and copper. In the area of aluminum, copper inclusions were observed, and in the area of copper, aluminum inclusions were observed in the form of particles and thin lamellas. The bottom side of the joint consists mainly of copper. X-ray diffraction showed the presence of intermetallic phases Al2Cu, Al4Cu9 from the side of the shoulder. The formation of intermetallic phases occurred in the solid-state, without melting the initial materials. The presence of copper particles in the region of aluminum and aluminum particles and lamellas of various lengths in the regions of copper, intermetallic phases led to the formation of a composite-like structure. The formation of a composite-like structure during friction stir welding of copper and aluminum plates affects the mechanical properties of the joint. Thus, the microhardness of the joint increased in comparison with the microhardness of the initial plates. The distribution of microhardness over the thickness of the joint is almost uniform. The formation of composite-like structure using friction stir welding are discussed.

Wet ball milling and subsequent high-speed selective laser sintering of Nb[sbnd]Cu powders for applying wear-resistant coatings

The work investigates niobium-carbohydride- and copper-based powders prepared via wet ball milling of niobium and copper in petroleum ether, including their phase composition evolution under heat treatment. High-speed selective laser sintering of the prepared powders on iron substrates provides gradient coatings ~70 μm thick. The outer layer of the coating contains phases of NbC0.75, Nb2C, (Fe,Nb)6C, Cu, and Fe, whereas the 10-μm layer adjacent the substrate shows the presence of NbC0.75, (Fe,Nb)6C, Fe2Nb, Сu, and Fe. Dry friction with a WC–Co counterbody does not cause wear of the coatings, and the friction coefficient being ~0.6. High wear resistance of the coatings results from their structure including regions containing nanosized niobium carbides (50–500 nm) with a hardness of ~11 GPa, regions of Fe + Fe2Nb eutectic reinforced with niobium carbide inclusions with a hardness of 6.5 GPa, and copper inclusions working as a solid lubricant in tribological tests.

Work on the cutting edge: metallographic investigation of Late Bronze Age tools in southeastern Lower Austria

This paper analyses 20 Late Bronze Age (ca 1080–800 BC) copper alloy objects to discern their manufacture and the skills of local craftsmen. Several tools and jewellery were studied that originated from a bronze workshop located immediately next to the Prigglitz-Gasteil copper ore mining site and several contemporaneous sites in the surrounding area. The samples were studied with optical microscopy (microstructurally), and SEM-EDXS and XRF (chemical analyses). Our analyses are part of a larger study and suggest that the Prigglitz region’s bronze production was not standardized. Particular alloys do not seem to have been chosen for object types or due to their intended use-function. Notably, approximately 20% of the objects contain unalloyed copper inclusions, which are most likely a result of the incomplete mixing of scrap metals and alloys during their production.

Electrodeposition of chitosan enables synthesis of copper/carbon composites for H2O2 sensing

This work presents a novel approach in synthesizing copper (Cu)/carbon composite materials by electrodeposition of the biopolymer chitosan, a renewable carbon precursor, on a copper anode, followed by pyrolysis of the electrodeposited chitosan gel. The amount of copper in the Cu/carbon composite material can be controlled by modifying the pH of the chitosan solution from which the electrodeposition is performed. This further influences the physical properties of the composite material. Here we show a 14 fold increase in electrical conductivity of the Cu/carbon composite, when compared to the material without copper inclusions. Metal/carbon composite materials have a wide range of applications already reported in the literature. As a proof of concept, we demonstrate the electrochemical sensing capability of this Cu/carbon material for non-enzymatic detection of hydrogen peroxide, achieving a sensitivity of 58.9 μA/mM cm2, which is comparable to state of the art non-enzymatic hydrogen peroxide sensors. The anodic electrodeposition of chitosan proves to be a simple and straightforward medium for synthesis of Cu/carbon composites. We speculate that this method can be extended to obtain other metal/carbon composites as a low-cost alternative for the fabrication of functional composite electrodes.

The properties of oxide-ceramic layers with Cu and Ni inclusions synthesizing by PEO method on top of the gas-spraying coatings on aluminium alloys

Based on thermodynamic calculations, the possible options for forming of oxide-ceramic layers (Al2O3) alloyed with copper and nickel inclusions have been considered. For this purpose, plasma-electrolyte oxidation (PEO) of the directly aluminum alloys surfaces or the gas-thermal coatings sprayed on top of them was used. A sequence of reactions occurring in plasma channels during PEO is proposed. Experimental verification of the obtained oxide-ceramic layers was carried out at the different types of tests. All analyzed oxide-ceramic layers were characterized by high elasticity modulus, hardness and wear resistance. A selective mass transfer effect was detected during friction of the oxide-ceramic layers (alloyed with dispersed copper inclusions) with cast-iron in the boundary lubrication conditions in the motor oil with glycerine addition. The glycerate films of iron and copper were formed during friction process on the surfaces of friction elements. As a result of the friction ratios and the wear resistance of such friction pairs was reduced by an order of magnitude. However, most importantly, the low values in friction coefficient were maintained even at high specific loads.

Gradient transition zone structure in “steel–copper” sample produced by double wire-feed electron beam additive manufacturing

This paper describes the results of an investigation into a microstructure formation on a wire-feed electron beam additive manufactured “steel–copper” bimetallic sample. The peculiarities of a gradient zone structure with a smooth change of components’ concentration are revealed. The heterogeneity of copper and steel distribution in the gradient zone is provided by copper solidification and precipitation mechanisms. Both solidification of coarse copper inclusions in the interdendrite areas or along the dendrite boundaries and precipitation of fine Cu-based particles at the cooling stage from the solid solution of Cu in γ-Fe are the main factors of structure formation during the double wire gradient zone deposition. The presence of such fine copper precipitates from the supersaturated solid solution was revealed by means of transmission electron microscopy. The shape of copper particles in the gradient zone varies from spherical to oblong and irregular. The shape of steel particles and/or grains is mainly determined by the peculiarities of the crystallization zone and is characterized by the primary crystallization of γ-iron dendrites from the liquid melt. A physical scheme describing a variation in phase composition and microstructure in gradient zone of the bimetallic specimen was proposed.

Investigations of surface defects during laser polishing of tool steel

During laser polishing of tool steel surfaces produced by electric discharge machining with NIR continuous wave laser, small craters were observed on the polished surface. Their formation was observed in situ with high-speed camera. Post mortem investigation of the composition of the craters with energy dispersive X-ray spectroscopy (SEM) has shown that they were caused by copper inclusions on the steel surface. The inclusions are probably coming from the electrode employed during the electric discharge machining process. The low absorption of copper in NIR signifies that the bigger copper particles do not melt at high speed which leads to the formation of the craters.

Peculiarities of Structure Formation in Copper/Steel Bimetal Fabricated by Electron-Beam Additive Technology

In the present paper, the microstructure of heterogeneous material bimetal compound fabricated by wire-feed electron-beam additive technology from CrNiTi stainless steel and С11000 copper has been investigated. The bimetallic compound is characterized by the well-defined interface between the two materials and possesses two-phase transition areas on both sides of the interface. The heterogeneity of strength properties (microhardness) in the transition zones is associated with a solid solution hardening of the bimetal basis components and formation of composite structures in the transition zone of the bimetal: spherical inclusions of steel in the copper part and copper inclusions in the steel section. In the copper part of the bimetal sample, a heterogeneous grain structure is formed – areas with macroscale non-equiaxed grain structure and zones with spherical grains were observed. The heterogeneity of grain structure does not have significant influence on the yield strength, but affects the macroscopic deformation pattern of the bimetal copper part, as has been revealed by microstructural analysis of slip traces and grain structure calculated using the Hall–Petch relationship.

Through the ‘Scope: Copper Inclusions in Quartz Microcrystals from Michigan's Keweenaw Peninsula

Twenty-seventh in a series of articles on the mines and minerals of Michigan's Copper CountryThe Lake Superior copper district is world famous for the copper-included calcite crystals that occurred...

Effect of Thermoelastic Characteristics of Components, Shape of Non-Isometric Inclusions, and Their Orientation on Average Stresses in Matrix Structures

The paper presents model calculations on which to predict volume-average external stress under changes of local internal stress in matrix composites with non-isometric inclusions. It is assumed that the rise of local stress owes to different coefficients of linear thermal expansion of non-isometric inclusions and matrix. The inclusions are taken as ellipsoids of rotation (disks, short fibers) and their principal semiaxes as oriented either along three mutually perpendicular directions x, y, and z of a rectangular coordinate system, only along x and y, or only along x. The average stress in the heterogeneous material and its local stress within an individual inclusion are related through a stress concentration operator (fourth rank tensor) for which an explicit expression is derived in a generalized singular approximation of random field theory. The relations obtained for external stress take into account thermoelastic characteristics of the two components as well as inclusion concentrations and orientations in the matrix. The calculation is applied to estimate the average stress along three axes in a composite consisting of an ED-20 epoxy binder and non-isometric copper inclusions.

Gibbs energy calculation of electrolytic plasma channel with inclusions of copper and copper oxide with Al-base

The oxide ceramic coating with copper inclusions was synthesized by the method of plasma electrolytic oxidation (PEO). Calculations of the Gibbs energies of reactions between the plasma channel elements with inclusions of copper and copper oxide were carried out. Two methods of forming the oxide-ceramic coatings on aluminum base in electrolytic plasma with copper inclusions were established. The first method – consist in the introduction of copper into the aluminum matrix, the second - copper oxide. During the synthesis of oxide ceramic coatings plasma channel does not react with copper and copper oxide-ceramic included in the coating. In the second case is reduction of copper oxide in interaction with elements of the plasma channel. The content of oxide-ceramic layer was investigated by X-ray and X-ray microelement analysis. The inclusions of copper, CuAl2, Cu9Al4 in the oxide-ceramic coatings were found. It was established that in the spark plasma channels alongside with the oxidation reaction occurs also the reaction aluminothermic reduction of the metal that allows us to dope the oxide-ceramic coating by metal the isobaric-isothermal potential oxidation of which is less negative than the potential of the aluminum oxide.

Carolingian and Ottonian Brass Production in Westphalia Evidence from the Crucibles and Slag of Dortmund and Soest

The abundant new crucible and slag finds from the Thier-Brauerei excavation in the center of medieval Dortmund have provided a stimulus to revive the discussion of Westphalian brass cementation technology in the Carolingian and Ottonian periods and to explore unanswered questions concerning the process and its potential outcome. A total of sixteen crucibles and slag samples from stratified deposits in the Dortmund-Thier-Brauerei and Soest-Plettenberg excavations were prepared for optical and scanning electron microscopy to analyze metallic inclusions, slag phases and crucible ceramic. The copper and brass inclusions within the crucibles and their adhering slag from Dortmund show a relationship between lead and zinc contents and indicate that lead-bearing calamine ore was heated with charcoal and copper metal to produce leaded brass. Ternary Cu-Zn-Pb alloys are common for contemporary bar-shaped ingots, which supplied casting industries in early medieval Northern European towns like Hedeby and Kaupang. Concerning the zinc-rich black slag lining the interior of some crucible fragments, they regularly showed increases in lime and iron oxides in relation to the crucible ceramic and thus reflect impurities coming from the zinc ore. The lead-silicate slags often found in association with crucible finds in Dortmund have yet to have a clear interpretation; although the lead isotope analysis of crucibles and lead-silicate slag shows they may have the same source of lead, the production of the lead-silicate slag is definitely unrelated to the metallurgical process occurring inside the cementation crucibles themselves.

Atomic scale understanding of the interaction between alloying copper and MnS inclusions in stainless steels in NaCl electrolyte

The effect of alloying copper on the dissolution of manganese sulphide which triggers the pitting corrosion of stainless steels was studied by in-situ ex-environment transmission electron microscopy (TEM) with an atomic resolution. It was found that the benefits of Cu addition act in two ways: Cu ions replace the Mn ions in the surface layer of MnS and insoluble copper sulphide compound forms; on the other hand, Cu ions could stabilize harmful surphur species released from dissolved MnS. The two processes are supposed to be helpful to reduce the detrimental effect of MnS on the corrosion resistance of stainless steels.

High dynamic stiffness mechanical structures with nanostructured composite coatings deposited by high power impulse magnetron sputtering

Nanostructured Cu:CuCNx composite coatings with high static and dynamic stiffness were synthesized by means of plasma-enhanced chemical vapor deposition (PECVD) combined with high power impulse magnetron sputtering (HiPIMS). Scanning electron microscope (SEM) images and energy-dispersive X-ray spectroscopy (EDS) mapping from cross-sectioned samples reveals a multi-layered nanostructure enriched in Cu, C, N, and O in different ratios. Mechanical properties of the coatings were investigated by Vickers micro-indention and model tests. It was observed that copper inclusions as well as copper interlayers in the CNx matrix can increase mechanical damping by up to 160%. Mechanical properties such as hardness, elastic modulus and loss factor were significantly improved by increasing the discharge power of the sputtering process. Moreover the coatings loss modulus was evaluated on the basis of indentation creep measurements under room temperature. The coating with optimum properties exhibited loss modulus of 2.6 GPa. The composite with the highest damping loss modulus were applied on the clamping region of a milling machining tool to verify their effect in suppressing regenerative tool chatter. The high dynamic stiffness coatings were found to effectively improve the critical stability limit of a milling tool by at least 300%, suggesting a significant increase of the dynamic stiffness.