Papers by Keyword: Cu-Sn

Abstract: The aim of this paper is to obtain the Cu-Sn-PTFE composite coating with wear-resistant and antifriction properties, which can improve the comprehensive performance of Cu-Sn coating and satisfy the self-lubricating property in special working condition. This coating was prepared by pulse current on the basis of non-cyanide pyrophosphate-stannate Cu-Sn plating bath. The effect of PTFE content on the microstructure, composition, microhardness, and tribological properties were analyzed and compared in detail. Results show that with appropriate PTFE content, the composite coating of Cu-Sn-PTFE displays preferable low friction and anti-wear behavior.

Abstract: Due to environmental concerns, lead-free solders were introduced to replace the lead-based solders in microelectronics devices technology. Although there are many lead-free solders available, the Sn-Ag-Cu solders are considered the best replacement due to their good wettability and joint strength. Although the Sn-Ag-Cu solders are accepted widely, but there are still some room for improvement. In this study, 1wt% Zn, which can be considered high percentage for a dopant, was added into the solder via powder metallurgy route. The effects of adding this dopant into the Sn-3.5Ag-1.0Cu solder on the interface intermetallic and thickness were investigated. The intermetallics phases formed were observed under Scanning Electron Microscope (SEM) and their thicknesses were measured. The SEM results showed the presence of Cu₆Sn₅, Cu₃Sn and (Cu,Zn)₆Sn₅ intermetallics. It can be concluded that Zn behaved as retarding agent and significantly retarded the growth of Cu-Sn intermetallics.

Abstract: The Cu-Sn composite is one of material for frangible bullet application. Frangible bullet are designed to disintegrate on impact against rigid surfaces to avoid ricochet hazards in shooting ranges or law enforcement training facilities. The manufacturing process of CuSn is based on powder metallurgy with variation of weight percent of Sn and compacting pressure. Sintering is performed at temperature of 260°C within 30 minutes period with nitrogen gas atmosphere. The secondary phase (Cu₃Sn and Cu₆Sn₅) was identified. The highest density and hardness are 7,446 g/cm³, 83 HRF for Cu-5 wt% Sn at 500 MPa. The pressure strength and modulus of elasticity are 275,72 MPa and 59,43 GPa.

Abstract: The bronze process is a mature technology for the production of Nb3Sn superconducting wires exploiting reaction diffusion behaviour in the Cu-Nb-Sn system. However, the superconducting properties depend strongly on the applied heat treatment, and optimisation of the heat treatment is still largely by trial and improvement. Modelling of the reaction-diffusion behaviour would allow improved heat treatments to be designed; combination of this with a nondestructive in situ characterisation technique would also permit improved superconducting wires to be produced. A finite difference reaction diffusion model has been designed to permit rapid calculation of the bronze matrix composition and Nb3Sn layer thickness profiles across the wire cross-section as a function of time for any applied heat treatment. The model has also been designed to calculate the electrical resistivity of the wire, which has previously been demonstrated as a suitable in situ characterisation technique. This model has been applied to isothermal and more complex heat treatments and compared with experimental results. Good qualitative agreement has been found, and plans for further improvement of the model are described in detail.