Papers by Keyword: Copper Substrate

Abstract: The different composition material of copper substrate significantly affects the intermetallic compound (IMC) formation and the solder joints durability. This study was conducted on the interfacial reaction between lead-free solder and the different copper substrates via reflow soldering. The selected substrate is copper (Cu) and copper-beryllium (Cu-Be). The lead-free solder involved is Sn-3.8Ag-0.7Cu (SAC3807) solder ball with a diameter of 700 μm. All the samples were subjected to the isothermal aging process. The material characterization and analysis on the IMC formation were examined by scanning electron microscopy (SEM), optical microscope (OM), and energy dispersive X-ray analysis (EDX). After the reflow process, the result revealed that Cu₃Sn, Cu₆Sn₅ IMC layer formed at SAC3870/Cu and SAC3870/Cu-Be interface. The changes to a rod-like shape Cu₆Sn₅ and irregular needle-shaped Cu₃Sn₄ occur after the aging treatment on SAC3870/ Cu. Meanwhile, the IMC layer for SAC3870/Cu-Be shows a rod-like shape transformed into a blocky-like shape Cu₆Sn₅ and Cu₃Sn₄ diamond-shape. This result indicates that Ag₃Sn nanosized was formed on the intermetallic surface during the aging process for both SAC3807/Cu and SAC3807/Cu-Be. The Ag₃Sn nanosized element at SAC3807/Cu-Be is many compared to SAC3807/Cu. In addition, IMC thickness for SAC3807/Cu-Be shows a thicker layer than SAC3807/Cu. Lastly, in this research, the element of Be in SAC3807/Cu-Be cannot be defined because the beryllium element is not easily detected as the percentage was very low.

Abstract: Diamond films were grown by hot filament chemical deposition (HFCVD) on Cu metal substrate with two different buffer layers (SiC or MoSi2) synthesized by using magnetron sputtering technique. The components of films were investigated using X-ray diffraction (XRD) and laser Raman spectrum, and the surface morphology and structure were observed with scanning electron microscopy (SEM). Film adherence was investigated by micro-indentation. The results showed that the diamond films were successfully grown on Cu metal substrate with two different buffer layers. There were cracks on diamond film grown on 3µm SiC buffer layer and some SiC crystal whiskers were observed. Dense diamond films with bad adhesion were observed on 22µm MoSi2 buffered copper substrate. MoSi2 made chemical reaction with CH4 and produced MoC and Mo5Si3 on the process of HFCVD. Conclusion: the 3µm buffer layer of SiC can’t help deposit no cracking diamond film; the 22µm buffer layer of MoSi2 is helpful for depositing good diamond film, but can’t effectively improve the bond strength between diamond film and copper substrate.

Abstract: By pulse magnetron deposition method the heat-shielding coatings on the basis of Zr-Y-O/ Si-Al-N layers on copper substrate are formed. Surface layer of copper substrate was treatment by the Zr⁺ ions. Structure-phase states were investigated by TEM, SEM, X-ray and SIMS. Thermal cycle durability of coatings is defined.

Abstract: Superhydrophobic surfaces on metal substrates are often prepared via roughing the surfaces and lowering their surface energy. Composite brush plating technique is developed to prepare superhydrophobic n-SiO₂/Ni brush plating composite coating on copper surfaces. Under the better process parameters, the water contact angle of the obtained superhydrophobic surface is approximately 160°, and the water sliding angle is less than 10°. The influences of plating voltage and plating time on the coating surface structure and hydrophobicity were discussed. The surface morphology and chemical composition were characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS).The results show that the prepared surfaces have the appearance of the uniform micron papilla-like structures, which are composed of submicron globular Ni particles covered with n-SiO₂ nanoscale villiform structures. These hierarchical micro/nanostructures are similar to the lotus leaf and play an important role in gaining superhydrophobicity. It is expected that this sample technique will be widely used for large-scale production of superhydrophobic engineering materials.

Abstract: The non-cyanide silver electroplating on copper substrate has been discussed. Based on the surface morphology by using SEM, the smooth and fine silver layer is obtained. The influences of concentration of silver and plating temperature on the thickness of the plating layer are discussed, the thickness of the silver layer is increasing with silver concentration rising and plating temperature rising.

Abstract: In order to improve the surface Performance of thick copperplate, A Ni- Cr alloy coating metallurgically bonded onto thick copperplate is performed by YAG laser remelting plasma spraying coating process. In laser cladding processing, it is difficult to get good metallurgical bonding between the layer and copperplate. Plasma spraying technology is developed to get a alloy layer on the surface of thick copperplate, and then using YAG laser cladding method to make a coating. The results of Micro organization analysis indicate that the cladding layer and substrate form favorable metallurgical bonding, as a narrow metallurgical bonding zone, about 3m in thickness. The structure is more compact compared with witch of plasma spraying coating, and the crystal grains are refined grain.

Abstract: In order to improve the service life of copper crystallizer, a layer of Ni-based alloy on thick copperplate surface was performed by plasma spray process, and then YAG pulsed laser was used to remelt spray coating. Microstructure analysis, hardness test, and the wear resistance comparison experiments were taken to the specimen. The result shown that the Ni-based alloy cladding, metallurgy bonding with the copperplate, can be performed by taking the method of the YAG laser remelt technology; the structure of the cladding is compact, without defects such as pores and cracks. The micro hardness of cladding zone is between 450-490HV, which is much higher than that of the copper substrate (about 90 HV). The wear tests showed the laser cladding layer performed 14 times higher wear resistance compared to copper substrate.

Abstract: To achieve the welding of the larger copper substrate and iron parts, the new method of laser-TIG (Tungsten-arc Inert-Gas welding) hybrid welding is proposed. Experiment shows that the Ni-Cr alloy cladding layer is firstly prepared by YAG laser on the welding body of copper surface, it is metallurgically combined with copper substrate, and then the 5 mm diameter iron cylinder is welded by TIG welding in the cladding layer. The welding zone is fine, no weld cracks is observed under the microscope, metallographic analysis shows that copper and iron is the metallurgical bond.

Abstract: Copper has some excellent performances in anti-erosion and high thermal conductivity. It is applicable in many important fields. In the paper, two methods of preparing Ni-Cr alloy cladding layer on the surface of copper are proposed, including the spray welding and YAG pulse laser cladding .Then the Ni-Cr alloy layer prepared on the copper is investigated by optical microscopy, there is no hole and crack in the cladding layer. The experimental results show the coating is metallurgically bonded with the substrate. In comparison to the prepared cladding layers, the Ni-Cr cladding layer prepared by YAG pulse laser is the better, the size of copper is not restricted, and the copper substrate isn’t preheated.

Abstract: In rocket engine combustion chambers, the cooling channels experience extremely high temperatures and environmental attack. Thermal protection can be provided by Thermal Barrier Coatings. Due to the need of good heat conduction, the inner combustion liner is made of copper. The performance of a standard coating system for nickel based substrates is investigated on copper substrates. Thermal cycling experiments are performed on the coated samples. Due to temperature limitations of the copper substrate material, no thermally grown oxide forms at the interface of the thermal barrier coating and the bond coat. Delamination of the coatings occurs at the interface between the substrate and the bond coat due to oxide formation of the copper at uncoated edges. In real service a totally dense coating can probably not be assured which is the reason why this failure mode is of importance. Different parameters are used for thermal cycling to understand the underlying mechanisms of delamination. Furthermore, laser heating experiments account for the high thermal gradient in real service. Pilot tests which led to a delamination of the coating at the substrate interface were performed successfully.