Papers by Keyword: Copper Matrix

Abstract: Effects of graphite content, and sliding speed on the tribological characteristics of copper-graphite composites under dry sliding condition were evaluated using a pin-on-disc tribometer. The worn surfaces of the composites were analyzed through Scanning Electron Microscopy (SEM). The experimental results revealed the improvement in wear resistance with increasing graphite content. The friction coefficient is also gradually decreasing upto 25 vol% graphite. Sliding speed has an effect on copper (5-15 vol%) graphite composites where as sliding speed has no effect in copper-(20-30 vol%) graphite composites. This difference is attributed to availability of self-lubricating graphite layer at the contact zone.

Abstract: The reasearch shows that when the mass ratio of copper to iron is equal or greater than 100, the influence of copper on the determination of trace iron can not be ignored. To eliminate the interference, the polypropylene radical strong base anion ion exchange fiber was taken as the solid phase extraction solvent. Extraction and separation of trace iron (Ⅲ) from solution copper (Ⅱ) by the extraction solvent was studied. The extraction conditions including of adsorption and elution were optimized. The strong base anion ion exchange fiber was put into the analysis solution with the medium of 6mol/L HCl. After adsorption 1h by vibration on the oscillator, adsorptive iron(Ⅲ) was eluted with the 1mol/L HCl. The concentration of iron (Ⅲ) in the eluate solution was mesured by inductively coupled plasma atomic emission spectrometry (ICP-AES). The results showed that the residual Cu (Ⅱ) in the eluate solution did not affected the accurate determination of iron. The iron in metal copper, copper oxide and copper nitrate were separated and determinated, and the RSDs(n=3) were between 2.3% and 4.2%, the recoveries were between 96% and 103%, the detection limit of the method was 0.011μg/mL.

Abstract: Copper matrix composite with pure copper matrix reinforced with high modulus carbon fibres Thornel K 1100 was prepared by gas pressure infiltration technique. As-received composite was subjected to thermal expansion and thermal conductivity measurements in longitudinal and transversal directions. Large anisotropy of properties as well as surprisingly good structural stability has been observed. The mean coefficients of thermal expansion as low as 0.8 x 10-6 K-1 in longitudinal and as high as 23.5 x 10-6 K-1 in transversal directions were determined, the thermal conductivities as high as 650 Wm-1K-1 in longitudinal direction and as low as 60.7 Wm-1K-1in transversal directions were measured.

Abstract: The purpose of this work is to investigate and understand the thermomechanical behaviour of copper matrix composites with long fibres. The effects of the volume fraction of fibres are considered in this analysis. A micromechanical finite element model has been used to study the behaviour of the copper matrix composites reinforced with tungsten fibres, which undergo thermal cycling conditions. Furthermore, regular and random arrangements of fibres are considered

Abstract: A micromechanical model is employed to investigate the influence of the interface between the fibre and the matrix of a metal matrix composite with long fibre, which is elaborated through finite element method. Also, transverse properties of composite are studied in the present work. The interface, between the fibre and the matrix, is studied employing cohesive elements. These elements employ a cohesive zone model, which follows a bilinear law.

Abstract: Copper film was plated on Al2O3 ceramic powder in Al2O3 ceramic with copper matrix. The influence of copper film plated on Al2O3 ceramic powder to friction coefficient and amount of wear has been studied in this paper. Variance analysis shows that copper film on Al2O3 ceramic powder does not have significance influence to friction coefficient, but has significance influence to amount of wear of Al2O3 ceramic with copper matrix. Amount of wear of Al2O3 ceramic with copper matrix decreases with the increase of copper film plated on Al2O3 ceramic powder initially. When the copper film plated is beyond 47%, The amount of wear reaches a stable volume, and almost does not reduce again with the increase of the copper film plated on Al2O3 ceramic powder. To Al2O3 ceramic with copper matrix in this paper, the optimum copper film plated is 47%.

Abstract: Graphite is introduced into Al2O3 ceramic with copper matrix. The influence of graphite content to friction factor and wear and tear of Al2O3 ceramic with copper matrix has been studied in this paper. Friction factor of ceramic with copper matrix decreases with the increase of graphite content at first. After graphite content exceeds more than 3%, friction factor stops reduction. Wear and tear decrease with the increase of graphite content from the beginning. After graphite content surpasses more than 3%, it increases instead with the increase of graphite content. When graphite content is 3%, Wear and tear locates the lowest point. Solid lubrication film formed by graphite on the friction surface is the cause that makes friction factor drop.