Papers by Keyword: Nickel Plating

Abstract: Grinding is an important and very frequently used technology, allowing for significant gains in surface integrity. Products which have undergone surface treatment are often used in engineering. The required surface quality after grinding is one of the most important parameters. Nickel coatings as protection against corrosion are used, erosion, abrasion and as a material for the renovation of worn-out parts. This paper discusses the change of cutting conditions when samples were ground. The surface of the samples was treated with galvanically applied nickel. The data shows what level of surface roughness is achieved when choosing different cutting conditions. The results were evaluated on the basis of a comparison of the parameters of roughness. The input parameters were chosen on the basis of the practice, which was in the area carried out.

Abstract: Despite of its excellence magnetic quality, one of the critical properties of PrFeB based permanent magnet is a low corrosion resistance so it can be oxidized easily which can reduce its magnetic properties. In this study, Nickel coating has been performed for bonded PrFeB magnet by the electroplating method using Nickel-Watts bath-type as the electrolyte to improve the corrosion resistance. The varying amount of the electrolyte compounds used to have the optimized composition indicated by the corrosion resistance measurement. The solution composition used was NiSO₄ (230-380 g/L), NiCl₂ (30-60 g/L), and H₃BO₃ (30 and 45 g/L) with a fixed value of other parameters. Characterization used including the immersion corrosion test, microstructure analysis, and magnetic properties. Based on the corrosion rate measurement, the highest corrosion resistant of Nickel coated PrFeB magnet achieved from the electrolyte composition of NiSO₄: NiCl₂: H₃BO₃ = 380: 60: 30 g/L with a plating time and current density (J) of 60 minutes and 40 mA/cm² respectively. The corrosion rate data showed that the Nickel metal coating can improve the corrosion resistance of bonded PrFeB magnet up to 29 times than of the substrate. The SEM images showed that the thickness of the Nickel coating on the optimum electrolyte composition was in average value of 35.1 µm. The overall samples has a magnetic remanence value (B_r) reached ≥ 6 kG, so it has enough properties to be applied in devices such as generators and electric motors.

Abstract: In this paper, we got Ni-MWNTs through pretreatment of MWNTs and electroless plating of nickel, and observed the Ni-MWNTs and MWNTs with TEM and FTIR. In addition, we prepared Ni-MWNTs/EP and MWNTs/EP composites. The volume resistivity、permittivity and permeability of composites were measured. Results showed that the volume resistivity of Ni-MWNTs/EP was higher than MWNTs/EP’s when volume fraction was lower than 8%. The ε" of Ni-MWNTs/EP was larger than MWNTs/EP’s. It indicated that Ni-MWNTs/EP had better electromagnetic energy storing and consumption capacity. And the permeability of Ni-MWNTs/EP would increase with the increasing of Ni-MWNTs. Ni-MWNTs/EP had some ferromagnetism.

Abstract: SiCp/A356 composites containing 20% (volume fraction) SiC and three kinds of different filler metals were investigated by vacuum brazing process. Brazability of SiCp/A356 composites was analyzed after nickel plating on the surface of composites and without nickel plating process. The effects of holding time on microstructure of the brazed joints of SiCp/A356 composite were studied by metallographic microscope, SEM and Energy spectrum analysis. The results showed that nickel plating on the surface of composite contributed to improve brazability of SiCp/A356 composites prominently, while inferior brazability displayed without nickel plating on the surface of composites. Hardness of joints brazed at holding time of 6 min, 8 min and 10 min were studied, consequently the hardness of the weld seam region is the highest when the holding time was 8 min.

Abstract: A short electroless Ni-P plating process for preparing EMI shielding wood-based composite was studied. Birch and Fraxnus madshurica veneers were used as the substrate. It is a simple method that Ni-P coating was easily deposited on the surface of two kinds of veneers. The plated specimens were observed by SEM that the films are uniform, compact and continuous. EDS results shows that the coating contains 4wt% phosphorus and 96wt% nickel. It is indicated by XRD analysis that the film on the two kinds of veneers are crystalline. It was measured that the two wood-based composites have better electromagnetic shielding performance if more than 60dB in the frequency ranges from 9k to 1.5GHz.

Abstract: To increase the manufacture efficiency of electroplated diamond tools, a nickel plating solution containing ammonium sulphate and sodium formate was investigated. The effects of concentration of ammonium sulphate, sodium formate and pH value on throwing power, covering power, ability to resist Cu2+ contamination and deposit microhardness were studied. Surface topography of deposits was also observed by SEM. Compared to watts bath, the plating solution studied is advantageous in terms of the performance of plating solution, deposit hardness and diamond bit behavior. Ammonium sulphate can refine deposit crystal grains and result in crystal form change.