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Effect Of Rear Earth On The Structure And The Performance Of AlCrN Films Used Vacuum Arc Deposition Technology

Posted on:2008-12-24Degree:MasterType:Thesis
Country:ChinaCandidate:Y H LiFull Text:PDF
GTID:2121360215461981Subject:Materials Processing Engineering
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On the basis of AlCrN films, which were made by Bulat-6 multi-arcs ion plating machine using VAD methods, we had made AlCrREN films using Rear Earth as doping elements. In order to let the Rear Earth elements joined in the AlCrN films, we used Al/RE and Cr targets to deposit films. We also used IBAD methods to deposit AlCrREN films under the same technological conditions. SEM was adapted to observe the films' surface and sectional topography. The structure of AICrREN films was determined by XRD machine. The microhardness test machine and the friction wear testing machine were used to test the films' mechanical properties. Subsequently, we analyzed the high temperature oxidation resistance of the films. From the data got from above, we studied the affection of the films, such as structures, topography, microhardness, friction wear performances and high temperature oxidation resistance, which created by the doping of Rear Earth elements and IBAD methods.It is indicated that Rear Earth are surface-active elements. Rear Earth elements not only reduce the surface energy of the grains, but also enhance the ratio of nucleation. Otherwise, it has a little solid solubility in aluminum, that is, it almost not dissolve in aluminum. So, Rear Earth can refine the cast structure of aluminum alloys and upgrade the stability of the arc starting and the ability of anti-ablation.It is possible to create an interlayer before we deposited the AlCrN films. We found that used chromium as an interlayer can improve the high temperature oxidation resistance of AlCrN films obviously. With this process, we pulled Rear Earth elements (lanthanum, yttrium and cerium) into AlCrN films to form the multivariate AlCrREN films. The micro alloying of Rear Earth elements had active the composite and structure of AlCrN films. Firstly, the surface condition had been improved by the reduction of the shape and number of the drippings. Secondly, the cross-section structure of the films exhibited columnar crystals, which grow tightness and uniform. Thirdly, IBAD technology disturbed the growing of nucleates. The main phase, AlN (220), and phase CrN (220) were offset to small angle and the intensity decreased. The preferred orientation of Cr2N had reduced sharply along with (110) orientation. Meanwhile, with the addition of Rear Earth elements, the microhardness, friction wear performance and high temperature of AlCrN films also had been improved.We had done much work on the high temperature oxidation resistance of the AlCrREN films. It is conclude that there were compact oxide films, Al2O3 and Cr2O3, after high temperature oxidation. The ability of high temperature oxidation resistance of the films had been improved after the doping of Rear Earth elements. Rear Earth elements can reduce the growing rate and adhesion of the oxide films. So, the oxygen atoms were not easy to penetrate into the substrate from the oxide film and exhibited good high temperature oxidation resistance.At last, we found that lanthanum can improve both the stability of the arc starting of the target and high temperature oxidation resistance obviously.
Keywords/Search Tags:Rear Earth, vacuum arc deposit, AlCrN, high temperature oxidation resistance
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