Zibo Institute of New Material Research

Zibo, China

Zibo Institute of New Material Research

Zibo, China
SEARCH FILTERS
Time filter
Source Type

Liu H.,Shandong Polytechnic University | Guo R.-X.,Zibo Institute of New Material Research | Bian J.-S.,Shandong Polytechnic University | Zhong H.,Shandong Polytechnic University | And 2 more authors.
Cailiao Gongcheng/Journal of Materials Engineering | Year: 2011

The microstructural characteristics of the amorphous electroless Ni-W-P coatings before and after laser crystallization were evaluated by a quantitative XRD method. Wear behaviour of the coatings were investigated by means of measurement of microhardness, wear test and optical microscope and SEM observation. The results indicate that crystalline reaction of Ni 3P phase occurs at different scanning velocities. The crystallization degree of the coating increases with the decreasing scanning velocity, but there is an incomplete crystallization for all coatings. At the scanning velocity of 7mm/s, the crystallization degree is 73.0%. The size of precipitated Ni 3P is larger than Ni at the scanning velocity (10mm/s) of critical precipitation of Ni 3P phase. The evolution of magnitude of both phases is opposite while the scanning velocity decreases. The sizes of both phases are in the range of nano-scale during the process of laser crystallization. Microhardness and wear resistance of the coating before and after laser crystallization are affected by the crystallization degree, relative proportions of Ni and Ni 3P phases as well as grain sizes. Adhesive wear dominates at 7mm/s, and abrasive wear is the major form of the coating at 8mm/s. The wear resistance of the coating can be improved with fitting crystallization degree and suitable sizes of both phases.


Liu H.,Shandong Polytechnic University | Guo R.-X.,Zibo Institute of New Material Research
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2012

Two kinds of Ni-4.9%W-xP (x is 11.26% and 5.98%, respectively) coatings were prepared by electroless deposited method. Effects of phosphorous content on microstructural characteristics, including degree of crystallization, grain size and lattice strain of the coatings before and after annealing treatment were investigated by a quantitative XRD analysis technology. Electrochemical corrosion behaviour of the coatings was analysed by measurements of polarization curves and electrochemical impedance spectra and observation of SEM for the coating surface morphology before and after corrosion. The polarization tests of the coatings under different heat treatment conditions in 0.5 mol H 2SO 4 solution show that their corrosion is uniform corrosion. The corrosion mechanism mainly depends on phosphorous contents and microstructure of the coatings after heat treatment. The EIS measurements of the coatings in 3.5% NaCl solution indicate that their corrosion is pitting corrosion. The corrosion mechanism mostly affected by defects, especially the porosity in the coatings. The more the number of pores are and the larger the size is, the easier the pitting corrosion occurs.


Liu H.,Shandong Institute of Light Industry | Guo R.-X.,Zibo Institute of New Material Research | Zong Y.,Shandong Institute of Light Industry | He B.-Q.,Shandong Institute of Light Industry
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2010

The evolution of amorphous electroless Ni-W-P coatings with different phosphorus content in the process of heat-treatment was investigated by means of SEM and a quantitative XRD method. The results show that when annealed at 400°C, the degree of crystallization for the coatings with 13.36% and 11.34% phosphorus tends to be the same, regardless of the phosphorus contents. Ni3P phase and Ni phase are detected in the amorphous Ni-W-P coatings annealed at temperatures between 400°C and 500°C, and the grain size of Ni3P is larger than that of Ni phase. However, when the temperature exceeds 500°C, the grain size characteristics is reversed. When the temperature reaches 700°C, some amorphous phase still exists in the coatings, and higher phosphorus content results in higher amount of Ni3P than Ni. Residual stress measured by XRD and lattice strain for the electroless deposited coatings treated within the temperature range of 400°C to 700°C exhibit similar trends with increasing temperature. The as-plated amorphous coatings present the maximum lattice strain and it decreases gradually with the crystallization of the coatings during annealing treatment.


Liu H.,Shandong Institute of Light Industry | Guo R.-X.,Zibo Institute of New Material Research | Zong Y.,Shandong Institute of Light Industry | Bian J.-S.,Shandong Institute of Light Industry | Li S.,Shandong Institute of Light Industry
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2011

The effects of addition of tungsten in Ni-P coating on behavior of annealing crystallization and grain size of the coating were examined by XRD method. Wear behaviour of the coatings were investigated by means of measurement of microhardness, wear test under unlubrication friction and SEM. The results indicate that the addition of tungsten increases the nanocrystallization degree of the as-plated and annealed Ni-W-P coatings, promotes the process of crystallization of Ni phase, and enhances the crystallization reaction temperature of Ni3P phase and the hardness of Ni-W-P coating compared to that of Ni-P coating. Adhesive wear dominates in the wear process for as-plated and annealed Ni-9.27%P coating. The addition of tungsten Ni-W-P doesn't change the wear behaviour of Ni-5.13%W-9.32%P coating in the as-plated and low-temperature-annealed conditions, however, the micro-cutting wear becomes the main wear wechanism of the coating annealed at high temperature(above 600°C).

Loading Zibo Institute of New Material Research collaborators
Loading Zibo Institute of New Material Research collaborators