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The objective of this paper is to show that in the framework of the mathematical model conceived by Zheng, Larson and Zhang [1] (to explain the Mn distribution in a thin BiMn/Bi cylindrical bar, grown in the Shuttle mission 51 -G experiment MRS77F075 [2]) can be proved that there exists an adequate initially nonuniform Mn distribution for which the deviation from a prescribed value of the Mn concentration in the first 70% of a thin BiMn/Bi bar, grown in a Bridgman- Stockbarger system, in zero gravity, is of order 10-3. In the theoretical part, the presentation of the mathematical model is followed by a general theorem of existence and uniqueness of the solution of the heat and mass transport equations in the melt. In the numerical part the Mn distribution in the melt and in the BiMn/Bi bar is computed for an initially uniform and for an adequate initially nonuniform Mn distribution, respectively. The deviation from a prescribed value of Mn concentration is estimated. [ABSTRACT FROM AUTHOR]

Recently, research has been conducted on nanocomposite thin films containing new additive elements in ZrN. In this paper, a method for depositing ZrCuSiN nanocomposite coatings using a ZrCuSi single target is presented. The ZrCuSi target that was used to easily deposit a ZrCuSiN coating in a mixed gas atmosphere (Ar + N2) was produced by a simple arc melting method (casting process). The effect of the nitrogen content was investigated by depositing a ZrCuSiN coating using alloy targets at various nitrogen gas flow rates (2, 4, 6, and 8 sccm). X-ray diffraction analysis of the ZrCuSiN coatings revealed a ZrN structure with a preferable orientation (200). As the nitrogen flow rate increased, the formation of o-Zr3N4 was dominant in the ZrN formation. A nitrogen gas flow rate of 4 sccm produced a coating with optimal ZrN and a-Si3N4 coordination and maximum hardness (41 GPa). Reciprocal friction tests of all coatings and uncoated carburized SCM415 steel in a 5W30 lubrication atmosphere demonstrated that the 4 sccm coating had the lowest friction coefficient (0.002). Therefore, our method has the potential to be an alternative surface coating technique for materials used in automotive engine parts and various other wear protection applications. [ABSTRACT FROM AUTHOR]

Generally, thin-film metal glass (TFMG) is deposited using two or more elemental targets. Thus, achievement of a homogeneous coating during mass production is difficult. As a new method of TFMG deposition, a single target with high glass-forming ability (GFA) has been used to improve the sputtering process, facilitating easy processing and broad application of sputtering targets. In this study, three kinds of targets (i.e., cast, amorphous, and crystalline targets) are prepared via casting and powder processes. The thermal and mechanical properties of the three targets prepared using the various methods are investigated, and the crystalline target is found to be the most thermodynamically and mechanically stable of the three alternatives. In addition, for TFMG deposited using the microcrystalline target, excellent compositional uniformity between the target and coating is achieved. Therefore, this study experimentally demonstrates that a fine crystalline target is most suitable for use as a multi-component single target in GFA manufacturing methods. These findings are expected to facilitate commercial use of TFMGs. [ABSTRACT FROM AUTHOR]