Influences of Y Addition on Mechanical Properties and Oxidation Resistance of CrN Coating

AbstractCr1-xYxN coatings were fabricated by reactive co-sputtering deposition and the Y content was changed by varying the Y target power. The influence of varying amounts of Y addition on the mechanical properties and oxidation resistance of CrN coatings has been studied. The results reveal that Y ions substitute Cr ions in Cr-N lattice forming the solid solution Cr1-xYxN coatings. Y doping has a beneficial effect on the improvements of hardness and adhesion of the coatings. After the oxidation in air at 850°C for 2h, The CrN coating with 1.2 at. % Y addition exhibits superior oxidation resistance than Y-free CrN coating, while over doping of Y produces detrimental effects on oxidation resistance of the coatings

Stabilization of the cubic phase of HfO2 by Y addition in films grown by metal organic chemical vapor deposition

Addition of yttrium in HfO2 thin films prepared on silicon by metal organic chemical vapor deposition is investigated in a wide compositional range (2.0-99.5 at. %). The cubic structure of HfO2 is stabilized for 6.5 at. %. The permittivity is maximum for yttrium content of 6.5-10 at. %; in this range, the effective permittivity, which results from the contribution of both the cubic phase and silicate phase, is of 22. These films exhibit low leakage current density (5x10(-7) A/cm(2) at -1 V for a 6.4 nm film). The cubic phase is stable upon postdeposition high temperature annealing at 900 degrees C under NH3. (c) 2006 American Institute of Physics

Designing amorphous/crystalline composites by liquid-liquid phase separation

The Cu-Zr-Ag system is characterized by a miscibility gap. The liquid separates into Agrich and Cu-Zr rich liquids. Yttrium was added to the Cu-Zr-Ag and Cu-Zr-Ag-Al systems and its influence on liquid immiscibility was studied. This alloying element has been chosen to check the effect of the heat of mixing between silver and the given element. In the case of Ag-Y system it is highly negative (-29 kJ/mol). The liquid becomes immiscible in the Cu-Zr-Ag-Y system. To the effect of Y addition the quaternary liquid decomposed into Ag-Y rich and Cu-Zr rich liquids. The Y addition increased the field of miscibility gap. An amorphous/crystalline composite with 6 mm thickness has been successfully produced by liquid-liquid separation based on preliminary calculation of its composition. The matrix was Cu38Zr48Al6Ag8 and the crystalline phases were Ag-Y rich separate spherical droplets. © (2014) Trans Tech Publications, Switzerland

Some characteristics of matroids through rough sets

At present, practical application and theoretical discussion of rough sets are two hot problems in computer science. The core concepts of rough set theory are upper and lower approximation operators based on equivalence relations. Matroid, as a branch of mathematics, is a structure that generalizes linear independence in vector spaces. Further, matroid theory borrows extensively from the terminology of linear algebra and graph theory. We can combine rough set theory with matroid theory through using rough sets to study some characteristics of matroids. In this paper, we apply rough sets to matroids through defining a family of sets which are constructed from the upper approximation operator with respect to an equivalence relation. First, we prove the family of sets satisfies the support set axioms of matroids, and then we obtain a matroid. We say the matroids induced by the equivalence relation and a type of matroid, namely support matroid, is induced. Second, through rough sets, some characteristics of matroids such as independent sets, support sets, bases, hyperplanes and closed sets are investigated.Comment: 13 page