Papers by Author: Yu Qiao Shan

Abstract: In this work, CrN/NbN nanometer multi-layers were deposited on the metal substrates by a dual-target DC reactive magnetron sputtering system. X-ray diffraction, Scanning Electron Microscope and Energy Dispersive Spectrometer were used to analysis the phase composition, crystal structure, surface morphology, fracture morphology and elemental composition of thin films. Micro Hardness Tester and wear-resistant experiments were used to test the hardness and wear properties of the films.

Abstract: TiN thin films were deposited by D.C reactive magnetron sputtering on glass and metal substrate. The relations between the technical conditions and the properties of the thin films are studied, According to control the intensity of gas pressure by changing the flux of Ar and N2, the structure of TiN films could be control. By changing the target power、N2 flux and substrate temperature, the relations between the technical conditions and the structure of TiN thin films were analyzed so as to produce the TiN thin films of excellent decorations, good corrosion resistance and high micro-hardness.

Abstract: The Al-Mg coatings were deposited on high-speed electro-galvanizing steel by using double-target DC magnetron sputtering. Numerous Al-Mg coatings were prepared with a range of different Mg-target power at different substrate temperatures. The morphologies and compositions were analyzed by SEM, EDS and XRD, the corrosion-resistance properties with different sputtering parameters were discussed by electrochemical measurement. It was found that with the substrate temperature increasing, the porosity decreased, meanwhile, higher substrate temperature resulted in more granular particles and an increased average particle size, but that did not affect corrosion properties obviously. The corrosion-resistance properties were found to be significantly affected by the targets power. As the power of Al-target and Mg-target were 900W and 200W respectively, the film acted the best corrosion-resistance property. Corrosion current density was approximately 4μA/cm2, decreased significantly compared with galvanized sheet. After analysis, the coating was mainly composed of Al12Mg17 which afforded sacrificial anode protection. As the Mg-target power over high relative to Al-target, the coating was composed of Al12Mg17 and MgZn2, the latter can cause micro-galvanic acceleration of corrosion.

Abstract: With the correlation in stochastic process applied to the experimental results, the surface during grinding and further lapping with abrasive jet finishing (AJF) restricted by grinding wheel was investigated with respect to auto correlation function (ACF) , cross correlation function (CCF) and power spectral density (PSD) analysis. The results indicated that AJF made the surface contour formed periodicity in a small range and removed fluctuation of the surface contour in low frequency greatly. The average spacing of the surface contour decreased and the machined surfaces changed from continuous parallel micro-groove and plough to randomly distributed discontinuous micro-pit with the increase of machining circles. The surface texture became fine and surface roughness was obviously improved. Furthermore, the isotropy surface and uniformity veins both parallel and perpendicular machining direction was attained by the finishing process to improve greatly the wearable capability of the workpiece.