Dissertation
Dissertation > Industrial Technology > General industrial technology > Materials science and engineering > Special structural materials

The Microstructure、Superhardness Effect and High Temperature Oxidation Resistance of VN/SiO2 and TiAlN/Si3N4 Films

Author WuYing
Tutor LiGeYang
School Shanghai Jiaotong University
Course Materials Science
Keywords VN/SiO2 nano-multilayers TiAlN/Si3N4 nano-multilayers Reactive sputtering Amorphous crystallization Superhardness effect Coherent interface Mechanical Properties High temperature stability
CLC TB383.2
Type Master's thesis
Year 2008
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High hardness and material combinations NANOMULTILAYERS diversity it has broad application prospects in the tool coating and surface modification field such material through the micro-structure to strengthen high hardness of superhard effects more theoretical research value . Recent studies show that the use of nano-multilayered film crystal growth \However, using this method to obtain with a the superhard effect NANOMULTILAYERS material combinations still need to experiment to explore. On the other hand, due to the high temperature stability of the tool to withstand high temperature rise in service NANOMULTILAYERS is the type of material used in the production of one of the key performance. This article was prepared by reactive sputtering method VN / SiO multilayers 2 nano vapor deposition, when usually the amorphous SiO 2 and Si , 3 N 4 VN and TiAlN crystal layer on the crystallization conditions, and VN / SiO the 2 , TiAlN / Si 3 N < sub> 4 nano growth of multi-layer film structure, superhard effect and strengthening mechanisms; examine the high temperature stability of TiAlN / Si 3 N 4 multilayers sex. The results show that: in a mixed atmosphere of Ar-N 2 V target and SiO 2 target reactive sputtering can be easily prepared by VN / SiO 2 nano-multilayers. In the the thus prepared VN / SiO 2 nano-multilayers, usually to amorphous SiO 2 its thickness is less than about 1nm, because VN crystal layer template effect and crystallized into the NaCl structure pseudospin crystal, and total epitaxial growth structure of a columnar crystal, the multilayer film presents a strong (200) texture the VN layer is formed having a clear interface. Accordingly, the hardness of the multilayer film has been significantly improved, maximum hardness reached 34GPa. With the further increase of the SiO 2 layer thickness, SiO 2 layer gradually transformed to amorphous, destruction of the multilayer film epitaxial growth, the hardness of reduced. Growth structure of the VN layer thickness increases NANOMULTILAYERS obvious, multilayer films with the the VN thickness of the increase remains epitaxial growth way, the hardness of the multilayers incremental gradually reduced to VN layer the thickness of 37nm, the multilayer film hardness and VN monolayer quite. As the reactive sputtering the VN has high deposition efficiency, high hardness nitride / oxide has broad prospects for industrial applications of nano-multilayers prepared using Ar-N 2 atmosphere. In TiAlN / Si 3 N 4 nano-multilayers the NaCl structure TiAlN mode layer can Si to 3 N 4 formed in less than 0.9nm crystalline state, formed with the crystal layer epitaxial growth structure TiAlN / Si 3 N 4 multilayers tension and compression stress field alternating its hardness corresponding improved the highest hard as 39 GPa. Further increase in Si 3 N 4 layer with thickness amorphous form of growth, the destruction of the multilayer film epitaxial growth, its hardness decreases . Temperature annealing, TiAlN / Si 3 N 4 multilayers modulation structure and crystal structure at 800 ℃ stable multilayers total alternating stress field of cell growth arising from the gradual disappearance of more than 600 ℃ superhardness effect disappeared. The study showed that the nano-multilayer film epitaxial growth of alternating stress field is strengthened micro-structural reasons.

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