Papers by Author: Li Qun Zhu

Abstract: Titanium alloys has been widely used in many fields, while in high temperature and rigorous corrosive environment, it is very necessary to do some work on the surface of titanium alloys to satisfy with application purpose. In this paper, four kinds of sol film were prepared on titanium alloys with and without anodic oxidation film. The prepared sol included Al2O3, Al2O3-ZrO2 and doped sol by adding additive into them respectively. The film thickness, high temperature oxidation resistance and corrosion resistance after high temperature oxidation for some time were investigated. The results show that the sol film obtained on the anodic oxidation film of titanium alloys is thicker than that without anodic oxidation film. Compared with the other three kinds of film, the doped Al2O3-ZrO2 sol film has the best high temperature oxidation resistance and corrosion resistance due to insulation effect of the sol film, and the composition of additive and zirconic.

Abstract: In this paper, the anodic oxidation film was prepared in the 1~3mol/L NaAlO2 solution with and without silicon sol added. The film thickness, high temperature oxidation resistance, corrosion resistance, and SEM image, element composition in the film were investigated. The results show that there were obvious improvement in high temperature oxidation resistance and corrosion resistance of the film on titanium alloys after adding silicon sol into the NaAlO2 solution, and with the sol percentage in the solution increased, the foregoing protection abilities of the anodic oxidation film became better, while the film thickness was little affected with the sol percentage difference. The reason was discussed and the effective factor was the silicon composition and more even and compact image in the film.

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: A new method has been devised to obtain a Zn coating on the AZ91D magnesium alloy from the base electrolyte of ZnSO4 and K4P2O7 by electroplating. To improve the properties of the coating, a SnO2 sol was prepared and added in the electrolyte. The effects of the SnO2 sol addition on the morphologies, compositions and phase structures of the plated coatings were investigated by scanning electron microscopy (SEM), energy dispersion spectrometry (EDS) and X-ray diffraction (XRD). The results reveal that the addition of SnO2 in the solution changes the polarization behavior of the electrolyte and the compositions of the plated coating. The plated coating formed in the electrolyte with an addition of SnO2 sol are more uniform and provide a better protection for the AZ91D substrate.