874 resultados para Mechanical properties of thin films


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Effects of alumina and chromium interlayers on the microstructure and optical properties of thin Ag films are investigated by using spectrophotometry, x-ray diffraction and AFM. The characteristics of Ag films in Ag/glass, Ag/Al2O3/glass and Ag/Cr/glass stacks are analysed. The results indicate that the insertion of an Al2O3 or Cr layer decreases the grains and influences the reflectance of Ag films. The reflectance of the Ag film can be increased by controlling the thickness of alumina interlayer. The stability of Ag films is improved and the adhesion of Ag films on glass substrates is enhanced by alumina as an interlayer.

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The variation of the structure, morphology and the electrical properties of thin amorphous silicon films caused by Rapid Thermal Annealing is studied. The films annealed at 1200degreesC for 2 minutes change their structure to polycrystalline and as a result their resistivity decreases by 4 orders of magnitude. Due to the small thickness of the as deposited amorphous silicon the obtained poly-Si is strongly irregular and has many discontinuities in its texture.

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GaN epitaxy films were grown on (0001) oriented sapphire substrate by metal-organic vapor deposition(MOCVD). AFM and SEM were used to analyze the surface morphology of GaN films. Hardness and critical load of GaN films were measured by an nano-indentation tester, friction coefficient by reciprocating UMT-2MT tribometer. It is found that the surface of GaN film is smooth and the epitaxial growth mechanism is in two-dimension mode, GaN epitaxy films also belong to ultra-hardness materials, whose hardness is 22.1 MPa and elastic modulus is 299.5 GPa. Adhesion strength of epitaxial GaN to sapphire is high, and critical load reaches 1.6 N. Friction coefficient against GCr15 ball is steadily close to 0.13, while GaN films turns to be broken rapidly by using Si3N4 ceramic ball as counterpart.

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The variation of the structure, morphology and the electrical properties of thin amorphous silicon films caused by Rapid Thermal Annealing is studied. The films annealed at 1200degreesC for 2 minutes change their structure to polycrystalline and as a result their resistivity decreases by 4 orders of magnitude. Due to the small thickness of the as deposited amorphous silicon the obtained poly-Si is strongly irregular and has many discontinuities in its texture.

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The electronic and mechanical properties of 5d transition metal mononitrides from LaN to AuN are systematically investigated by use of the density-functional theory. For each nitride, Six Structures are considered, i.e., rocksalt, zinc blende, CsCl, wurtzite, NiAs and WC structures. Among the considered structures, rocksalt structure is the most stable for LaN, HfN and ALIN, WC structure for TaN, NiAs structure for WN, wurtzite structure for ReN, OsN, IrN and PtN. The most stable Structure for each nitride is mechanically stable. The formation enthalpy increases from LaN to AuN.

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A kind of full-biodegradable film material is discussed in this article. The film material is composed of starch, PVA, degradable polyesters(PHB, PHB-V, PCL) with built plasticizer, a cross-linking reinforcing agent and a wet strengthening agent. It contains a high percentage of starch, costs cheap and is excellent in weather fastness, temperature resistance and waterproof and it could be completely biodegraded. The present paper deals mainly with a new technical route using a new type of electromagnetic dynamic blow molding extruder and some effects on mechanical properties of the system.