Influence Of Copper Content Research Articles

Influence of copper content and nanograin size on toughness of copper containing diamond-like carbon films

Five copper containing diamond-like carbon films (Cu-DLC), each with a particular content of Cu, were deposited on Si (100) substrates in an ion beam assisted deposition system. The influence of Cu content and nanograin size on film toughness has been investigated along with verifying through the microstructural, mechanical and sliding tribological behaviours of the films. Variation of Cu content and nanocrystallites dispersing in DLC matrix induces corresponding modification in film toughness as well as hardness, intrinsic stress and sliding frictional behaviour, resulting in improvement of film toughness for the combined tribological performances. The film toughness was investigated by scratch crack propagation resistance from the critical load data obtained from scratch test. Results revealed that doping Cu with nanograin sizes, especially at a suitable content of 10·5 at-%, will significantly improve the crack initiation resistance and propagation resistance of crack during scratch test, demonstrating the improved toughness.

Influence of copper content on the microstructure and hardness of copper-doped tungsten carbide–cobalt bulk at the elevated temperature

Ultrafine WC–Co cemented carbides doped with 0, 0.5, 1, 1.5 and 2wt.% Cu were fabricated by the sintering/hot isostatic pressing (sinter–HIP) process for the mixed WC and chemical precipitated Co–Cu powders. The Vickers hardness of cemented carbides was measured at temperatures ranging from room temperature to 800°C. The Cu-doped WC–Co alloys with the higher proportion of WC hard phase and finer microstructure of the average grain size of 590nm exhibit the higher hardness at the elevated temperature of 800°C. The Cu-doped WC–Co cemented carbides have a potential application in machining.

Microstructural evolution and tribological behavior of Mo–Cu–N coatings as a function of Cu content

Ternary Mo–Cu–N coatings with various Cu contents were deposited on Si wafers and AISI 304 substrates by magnetron co-sputtering from two elemental targets of Mo and Cu in Ar–N 2 gas mixtures. The influence of copper content was investigated with regard to the microstructure, morphology, and tribological properties of these coatings. The results indicated that the Mo–Cu–N coatings exhibited face-centered-cubic B1-MoN phase structure. No diffraction peaks of Cu phase appeared in the coatings with Cu content below 11 at.%. The copper segregated in the amorphous inter-granular phase in the coatings. Incorporation of Cu into the growing Mo–N coating led to grain refinement. The average friction coefficient of the Mo–Cu–N coatings decreased from 0.40 to 0.21 with increasing Cu content up to 11 at.% due to formation of lubricious oxides of CuMoO 4.

Influence of copper content on structural features and performance of pre-reduced LaMn 1-xCu xO 3 (0≤ x

A series of pre-reduced LaMn 1- x Cu x O 3 (0≤ x<1) catalysts for methanol synthesis from CO 2 hydrogenation were prepared by a sol-gel method. The catalytic performances were strongly dependent on the copper content. XRD investigation revealed that the single perovskite structure could be preserved after being reduced, when the substitution for Mn by Cu was less than 50%. The Cu-doped ( x=0.5) LaMnO 3 was much more active than the other catalysts for reaction, showing CO 2 conversion up to 11.33% and methanol selectivity close to 82.14%. The structural features of samples ( x≤0.5) were studied. It was determined that copper existed as Cu + species under reduction conditions. H 2 was adsorbed on Cu + sites and CO 2 was activated on the medium CO 2 active species in the lattice. The strong interaction between Cu + and Mn inhibited the further reduction from Cu + to Cu 0 and made the fine dispersion of medium basic site to adsorb CO 2, contributing to reactivity.

Shape evolution of Cu-doped Mn3O4 spinel microcrystals: influence of copper content

Spinel-type Cu-doped Mn3O4 microcrystals with various shapes were synthesized by hydrothermal method. The interrelation between the preparative conditions and the composition, structure, and morphology of the products were investigated using various analytical techniques, such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and thermal gravimetric analysis. Results revealed that the introduction of Cu2+ ions into the reaction system promoted the formation of single phase Cu-doped Mn3O4. A gradual shape evolution from polyhedron to octahedron occurred upon increasing the additive copper content. Complete decolorization of organic dye (methylene blue) aqueous solution was achieved by treating the dye with Cu-doped Mn3O4 in acidic media, which shows the possible application of doped Mn3O4 as effective reagents for the degradation of organic contaminants in water.

Comparison of the influence of copper micro- and nano-particles on the mechanical properties of polyethylene/copper composites

This article reports on the influence of copper content and particle size on the tensile properties of low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE) mixed with up to 25 vol.% Cu micro-particles and up to 5 vol.% Cu nano-particles, and on the influence of Cu micro-particle content on the dynamic mechanical properties of these polymers. This influence depends upon the extent of branching and crystallinity in the particular polymer. The copper micro-particles seemed to have a negligible influence on the tensile strength of LDPE and HDPE, while there was quite a significant reduction in tensile strength when LLDPE was used as matrix. The elongation at break generally decreased with increasing copper content, but the effect was more significant in the case of LDPE and HDPE. The tensile modulus generally increased with increasing Cu content, but the extent of increase was lower in the case of the more crystalline HDPE. The nano-copper containing samples showed comparable properties at equivalent Cu contents. The storage and loss moduli generally increased with increasing Cu. For all three polyethylenes the β-transition (where present) was not significantly influenced by the presence and amount of copper, but the α-transition was strongly influenced, especially in the case of LDPE and LLDPE.

A Study on the Influence of Copper Content in CrN/Cu Nanocomposite Thin Films Prepared by Pulsed DC Magnetron Sputtering

Synthesis of nanocomposite thin films of CrN/Cu deposited on (100) Si and D-9 alloy substrates by pulsed magnetron sputtering as a function of copper content in the range 15.1-35.8 at.% is investigated. XRD analysis of the films deposited at 773 K with nitrogen flow rate of 10 sccm indicated that the films are nanorystalline and bi-phasic (fcc-CrN and fcc-Cu). Scanning electron microscopy showed a structureless morphology for CrN, while agglomerates were obtained for CrN/Cu nanocomposite thin films. Atomic force microscopy also confirmed the agglomeration of particles with increasing Cu content. The amount of copper content in the nanocomposite films had also shown a significant reduction in the crystallite size of CrN. The nano hardness measurements showed a peak hardness of 17 GPa for the films with copper content of 15.1 at.%. The hardness values were found to decrease significantly with Cu content > 31.1 at.%.

The influence of copper on microstructure and mechanical properties of compacted graphite iron

The influence of copper content (0·26 to 1·31 wt-%) on microstructure formation and mechanical properties of compacted graphite iron (CGI) has been evaluated through standard metallographic analysis, colour etching techniques and tensile testing of machined test bars. The properties investigated are yield strength, tensile strength and elongation. The castings were made in an industrial environment from a combination of CGI returns, pig iron, cast iron- and steel scrap. A total of four heats were cast in specially designed sampling cups (3 different cooling rates), chill wedges as well as tensile test bars machined from sand moulded cylinders (20, 45 and 85 mm in diameter). The results clearly illustrate the combined effect of copper and cooling rate on nodularity, chilling tendency as well as pearlite content. A discussion concerning the effect of graphite morphology on the ferrite growth is also included.

The influence of copper content on intergranular corrosion of model AlMgSi(Cu) alloys

AbstractApplication prospects in automotive and aerospace industry have led to extensive studies on AA6xxx alloys in recent years. Varying amounts of Mg, Si and Cu and heat treatments are used to achieve the desired mechanical properties in these alloys. In this investigation, a series of tests have been designed and carried out on model AlMgSi(Cu) alloys to investigate the effects of Cu, Mg and Si composition and heat treatments on the corrosion properties for a range of Cu content levels (0.03, 0.15 and 0.80 wt%, respectively). The results indicate that the localized corrosion susceptibility of the model alloys primarily increased with Cu content. The Si and Mg content and ratio do not appear to have a significant effect on the local corrosion behaviour. Heat treatment can improve the corrosion resistance. However, this effect is small compared to that of the Cu content for the range of model alloys investigated. Intergranular corrosion will occur by micro‐galvanic coupling between the cathodic AlMgSi(Cu) (Q) phase precipitates and the aluminum matrix adjacent to the particles. The increasing susceptibility to intergranular corrosion with Cu content can be attributed to an increased formation of Q phase particles.

Preparation of 3D C/SiC-Cu Composites via Precursor Pyrolysis and Property Investigation

A novel composite, 3D C/SiC-Cu, which contained copper as transpiration agent, was designed and prepared. The influence of copper contents (2.18, 4.86, 6.53vol %) upon the mechanical and anti-ablative properties was investigated. The flexural strengths of three composites were over 450MPa, and fracture toughness over 15.0MPa•m1/2. After being ablated for 35 seconds in flowing oxyacetylene torch environment, the composites remained integral, and the flexural strength and strength retention ratio of the composite increased with the copper content increase. The maximum recession rate of the samples in oxyacetylene torch test was as low as 0.0490mm/s.

Removing and recovering gas-phase elemental mercury by Cu xCo 3−xO 4 (0.75 ⩽ x ⩽ 2.25) in the presence of sulphur compounds

The Hg 0 oxidation ability and reusability of Cu x Co 3− x O 4 were investigated in an attempt to improve SO 2 anti-poisoning ability of metal oxide and produce more economic and effective sorbents for the control of Hg 0 emission from combustion processes. The influence of copper content on Cu x Co 3− x O 4’s (0.75 ⩽ x ⩽ 2.25) oxidation ability of Hg 0 in the presence of SO 2 was investigated. According to the X-ray diffraction, Brunauer–Emmett–Teller (BET) and mass balance analysis on mercury, we found that Cu 1.5Co 1.5O 4 showed the highest S BET and best Hg 0 oxidation ability. With continuous increase of x from 0.75 to 2.25, Cu x Co 3− x O 4’s SO 2 anti-poisoning ability increased. The analysis results of the X-ray photoelectron spectroscopy manifested that the adsorptive mercury species on spent Cu 1.5Co 1.5O 4 was HgO. The spent Cu 1.5Co 1.5O 4 could be regenerated by thermal decomposition at 673 K and regenerated Cu 1.5Co 1.5O 4 showed higher Hg 0 oxidation ability due to Hg-doping. Regenerated enrichment Hg 0 was collected using activated carbon at an ambient temperature to eliminate the secondary pollution.

Evaluation and characterization of Mn–Cu mixed oxide catalysts for ethanol total oxidation: Influence of copper content

Mixed oxides of manganese and copper with different wt% of copper have been prepared and evaluated in ethanol combustion. The co-precipitation method used for the synthesis of Mn xCu y mixed oxides is adequate to obtain catalysts with excellent catalytic performance in combustion reactions. Catalysts were characterized by means of XRD, FT-IR, TPR and O 2-TPD. A small amount of copper prevents manganese oxide reaching a crystalline structure. This poor crystalline structure of manganese oxide may improve the existence of oxygen vacancies giving a best performance in ethanol combustion to CO 2. When the copper content increases, an extent of solid state reaction between Cu and Mn is favored and the partial oxidation of ethanol becomes more important. The incorporation of manganese into incomplete spinel structure diminishes CO 2 yield.

130 アトマイズ鉄粉のレーザ焼結特性及び積層特性に及ぼす銅含有量の影響(OS 粉末加工(1))

Sintering and lamination characteristics of Fe-Cu atomized powder have been investigated to meet requirements on recycling of automobiles and manufacture of lightweight structure. The greentape laser sintering method using Nd:YAG pulse laser and powder tape called "greentape" is employed for the fabrication of Fe-Cu porous structure. Extensively investigated is influence of copper content and laser parameters, such as voltage, pulse width and average power, upon the state of liquid sintering or both surface texture and tensile strength of the sintered specimens. A gas-atomized Fe-2mass%Cu powder (20um in mean diameter) is superior to the Fe-15mass%Cu one in monolayer tensile strength, but contains many pores. It is successful to laminate 16 layers of the greentape (190 jam in thickness each) at a voltage of 198V, a pulse width of 2.0ms and an average power of 13W. Porous structure can be controlled by altering these laser parameters as well as by varying copper content.

Influence of copper content on NO removal of the activated carbon fibers produced by electroplating.

In this study, the activated carbon fibers (ACFs) on which copper metal was deposited by electroplating were used to remove nitric oxide (NO). N(2)/77 K adsorption isotherm characteristics, including the specific surface area and micropore volume, were investigated by BET and T-plot methods. NO removal efficiency was confirmed by gas chromatographic technique. From the experimental results, the copper content supported on ACFs led to an increase in the NO conversion, in spite of the decrease of the specific surface area or the micropore volume of ACFs. Consequently, the presence of Cu on ACFs played an important role in improving the NO reduction into O(2) and N(2), which was mainly attributed to the catalytic reactions of Cz-NO-Cu.

Influence of Copper on Iron Corrosion in Weakly Alkaline Environment Containing Chloride Ions

The influence of copper content on the corrosion of iron has been investigated to make possible the use of scrap as a source material for reinforcing steel in concrete structures. An AC impedance technique was used to monitor the corrosion of iron, Fe-0.4 mass%Cu and Fe-3 mass%Cu undergoing cyclic wet-dry conditions with a 1 hour immersion in a pH 10 solution of Ca(OH) 2 containing 0.01 M NaCl followed by a 3 hour drying at 298 K and 50% RH. The corrosion rate of iron is greatly accelerated by wet-dry cycles. This is because active FeOOH species produced by the oxidation of Fe(II,III)oxide in air during drying act as very strong oxidants that promote corrosion in the wet condition. In each cycle, shortly before the surface dried out, a large increase in the corrosion rate was observed. This can be explained by the acceleration of oxygen transport through the thin electrolyte layer. Fe-0.4 mass%Cu showed a similar trend to iron. On the other hand, Fe-3 mass%Cu showed much lower corrosion rates and the corrosion was not accelerated by wet-dry cycling. Monitoring showed that the addition of 0.4 mass%Cu does not diminish the corrosion resistance of iron and the addition of 3 mass%Cu improves it under these wet-dry conditions. Energy Dispersive Analysis of X-ray (EDX) results indicated enrichment of copper in an inner rust layer after exposure to 56 wet-dry cycles.

Catalytic Activity and Hydrothermal Stability of Cu-ZSM-5 Used for the Decomposition of N2O

This article reports on the results of the influence of copper content and Si/Al ratio of the parent zeolite on activity and stability of Cu-ZSM5 used for the decomposition of nitrous oxide. Since H 2 O is present in all industrial exhaust gases, the influence of water vapor on the activity and hydrothermal stability of the catalysts used was also examined.

Influence of copper content on the fracture toughness of type D16 alloys

1. With a reduction in copper content from 4.2 to 3.1% the fracture toughness KIc of type D16 alloys increases by about 30% practically independently of the type of semifinished product, aging cycle, or sample orientation. 2. After artificial aging at 190 °C for plates in the VD direction the value of KIc is more and in the DP direction somewhat less than for bars. 3. An increase in aging time of D16 type alloys from 8 to 16 h at 190 °C leads to a decrease in fracture toughness which is greater for plates than for extruded bars.

Further Observations on A533-B Steel Plate Tailored for Improved Radiation Embrittlement Resistance

A series of advanced investigations on the radiation performance of four 6-in-thick plates from a large (30-ton) commercial melt of A533-B steel is described. The melt represented the first commercial scale demonstration test of improved radiation embrittlement resistance through the control (minimization) of selected residual impurity elements. Melt specifications emphasized the attainment of a low copper and phosphorus content; one half of the melt was modified, however, by a copper addition (0.03 percent Cu increased to 0.13 percent Cu). Initial plate tests described superior 550 F (288 C) radiation resistance, in terms of notch ductility retention, for the primary melt composition and verified the detrimental influence of impurity copper on irradiation behavior. Promising capability of the primary melt composition for very high fluence (∼2.5 × 1020 n/cm2 &gt; 1 MeV) service is shown by the current investigations. In addition, a significant influence of copper content on radiation resistance is revealed for a broad range of exposure temperatures. A dependence of 650 F (343 C) postirradiation heat treatment response (notch ductility recovery) on copper content was also found. Charpy-V versus dynamic tear test performance and tensile strength trends with temperature are examined for low (&lt;450 F, 121 C) and elevated (550 to 585 F, 288 to 307 C) temperature irradiation conditions.