Papers by Keyword: Ni–P Alloy

Abstract: In order to improve the corrosion resistance of sintered NdFeB magnet, experiments are done by the new process which involves ultrasonic electroforming Ni–P alloys. The influence of ultrasonic on electroforming Ni–P alloy on NdFeB was studied by using microscope, adhesion test and NaCl solution immersion test.The results showed that the Ni–P alloy deposit on NdFeB is rough and has poor adhesion without ultrasonic agitation; However, the Ni–P alloy deposit on NdFeB with ultrasonic agitation has the following advantages: uniform and smooth deposit grains, strong adhesion and good corrosion resistance.

Abstract: In order to improve the corrosion resistance of Nd-Fe-B, the new technological process is done which involves electroplating Ni–P alloys with ultrasonic. The influence of ultrasonic on electroplating Ni–P alloy on Nd-Fe-B was studied by using microscope, adhesion test and NaCl solution immersion test. The results showed that the Ni–P alloy deposit on Nd-Fe-B is rough and has poor adhesion without ultrasonic agitation; however, the Ni–P alloy deposit on Nd-Fe-B with ultrasonic agitation has more compact and uniform microstructure, smoother morphology. At the same time, the adhesion and corrosion resistance are greatly enhanced.

Abstract: In order to obtain stable and homogeneous diamond-Ni-P composite electroless plating, dispersants were selected by determining the height of emulsion in the colorimetric cylinder after standing different time.The structure,elemental contents and properties of the diamond-Ni-P composite electroless plating coating were investigated by SEM and EDS. Experimental results show that OP-10 of 50mL•L^-1 and softex kw of 1g•L^-1 have better dispersing effect to diamond powder of 1g•L^-1 in water. This composite electroless plating solution can keep stable for more than twelve or eight hours respectively at 85°C. While in the electroless plating solution, Softex kw of 1g•L^-1 has better dispersing effect and can be stable for more than two hours at 85°C. The diamond powder grains in the composite coating are homogeneous and the content of carbon is 2.261 wt% under the certain amount of the selected dispersant. When the content of diamond was 5g•L^-1 in the solution, the diamond powders were dispersed non-homogeneously in plating and cluster phenomena were appeared. The composite electroless plating coating consists of amorphous Ni-P and diamond powder. Its hardness and porosity are similar to those of the electroless plating Ni-P coating. The wear-resisting is improved greatly,which is 2.6 times of electroless plating Ni-P or 2 times of that after heat treatment at 400°C for one hour.

Abstract: In this paper, the effect of different concentrations of complexing agent on the surface of aluminum alloy plating Ni-P alloys is studied. Study the influence of malic acid complexing agents on the electroless Ni-P alloy deposition rate, morphology, corrosion resistance, and determine the optimal complexing agent concentration. The results show that when the malic acid concentration is 24g /L, the deposition rate gets to maximum, and coating uniformity, structure compact and corrosion resistance is best.

Abstract: Dispersants are selected and optimized by determining the height of emulsion in the colorimetric cylinder after standing in order to ensure the homogeneity of the powder and the stability of electroless plating solution. Experimental results show that non-ionic surfactants such as PEG6000,PEG10000,OP-10 have stronger emulsifying ability to α-Al2O3 powder in ordinary condition and IW has more stability at 80~90°C. The optimum conditions are suggested as PEG6000 8g, IW 0.95g and ethanol 3mL per 50mL solution. Moreover, this composite electrolessplating solution is stable for seven days under 90°C. Therefore it has more dispersing ability. The SEM images show that the powder in the coating is homogeneous. The electroless plating coating consists of α-Al2O3 and amorphous Ni-P that will change into crystal Ni3P and Ni-base solid solution after heat treatment at 400°C for one hour, the α-Al2O3 powders are dispersed evenly in the nickel matrix.

Abstract: In this study, a Ni-P alloy electroforming nanostructure material with low surface roughness and low internal stress was developed by using a pulse current. Square-wave cathodic current modulation was employed to electrodeposit ultrafine-grained Ni-P films from an additivefree Sulfamate nickel bath. The effect of various factors, such as peak current density, duty cycle and pulse frequency on the roughness and internal stress were investigated. Pulse current significantly influences the microstructure of Ni-P alloys. The internal stress and roughness of Ni-P alloys increased as peak current density increased, but the internal stress of Ni-P alloys decreased as duty cycle decreased.

Abstract: A tri-layer amorphous Ni-P alloy coating was prepared in the same bath by changing the temperatures and currents, followed by heat treament. We studied the behavior of corrosion-resistance of the tri-layer coating before and after heat-treatment at 360°C for different time in the 5% NaCl solution. The result showed that: the tri-layer amorphous Ni-P coating has the excellent performance of anti-corrosion compare with single electroless or electrodeposited Ni-P amorphous coating. The performance of anti-corrosion of the coating was improved by controlling the coating’s structure and the role of electrochemical protection. After being heat-treated at 360°C for 1 hour ,the coating’s structure changed from amorphous to crystalloid and the corrosion resistance of the heat-treated coatings was higher than as-plated tri-layer Ni-P coating.

Abstract: Tribological properties are found to change with microstructure. In Ni-P amorphous alloy, annealing conditions were varied with laser irradiation parameters such as scanning speed and laser power. The increase in hardness affected by scanning speed. A peak of hardness was observed as the function of scanning speed. This is because, the formation of nanoscopic composite structure by distribution of crystalline Ni3P compounds in amorphous matrix is the hardest structure.

Abstract: A novel tube-form asymmetrical carbon membrane based on phenol-formaldehyde resin (PFR) is proposed in this paper. The membrane is composed of Ni-P alloy on exterior surface of carbon support membrane by electroless plating method after adding ferrous powders (<20&m) as active particles inside the membrane procurer. The results show that the H2, N2 and CO2 permeation rate through the composite Ni-P carbon membrane decrease and gas separation factors increase with increase of Fe content, and H2, N2 and CO2 permeation rates reach 0.44, 0.10 and 0.08 m3.m-2.s-1.MPa-1, respectively; H2/N2 and H2/CO2 separation factors are 4.2 and 5.5, respectively. The morphology of the membrane is measured by Scanning Electron Microscope (SEM).