Microstructural Characterization and Anti‐Oxidation Properties of Molybdenum Disilicide Coating on Niobium by Spent MoSi 2 ‐Based Materials

2020 ◽  
pp. 2000691
Author(s):  
Lu Zhu ◽  
Xuanru Ren ◽  
Xueqin Kang ◽  
Ping Zhang ◽  
Peizhong Feng ◽  
...  
1982 ◽  
Vol 1 (1) ◽  
pp. 19-22 ◽  
Author(s):  
Seiji Motojima ◽  
Akiyoshi Fujimoto ◽  
Kohzo Sugiyama

2010 ◽  
Vol 442 ◽  
pp. 74-80 ◽  
Author(s):  
Aamer Nusair Khan

Titanium aluminides intermetallic compounds have received great attention during the past decade, since they have the potential, in aircraft and automotive engines, to replace the high density Ni-base superalloys However, these intermetallics possess poor oxidation properties at high temperatures. Previous studies showed that protective alumina scale formation on γ-TiAl can be obtained by small additions (around 2 at.%) of Ag. In the present study, a number of cast Ti–Al–Si alloys were investigated in relation to transient oxide formation in air at 1300°C. After various oxidation times the oxide composition, microstructure and morphology were studied by combining a number of analysis techniques. The TiAl–Si alloys appear to form Al Ti and Si oxides. However, the formation of silicon oxide at the interface of base metal and scale slows down the oxidation rate significantly.


2011 ◽  
Vol 686 ◽  
pp. 583-588 ◽  
Author(s):  
Jian Hui Yan ◽  
Si Wen Tang ◽  
Jian Guang Xu

Intermetallics molybdenum dislicied has a great potential as a protective coating in aircraft engines and gas turbines in the elevated temperature. The suit for plasma spraying MoSi2powders were prepared by spray drying process and vacuum sintered. The oxidation behaviors of the coating were determined at 1200 °C. The coatings as sprayed and oxidized were characterized by XRD, SEM and EDS. Results show that the flow ability and loose density of MoSi2powder by sintered treatment, were 17.1 s/50g and 2.1g/cm3, respectively, ideal for air plasma spraying. During the course of spraying, some of molybdenum disilicide with a tetragonal lattice was converted into molybdenum disilicide with a hexagonal lattice. Also, part of MoSi2 phase oxidized and transformed to Mo5Si3phase. A relative dense molybdenum disilicide coating was prepared by air plasma spraying. A protective SiO2layer, seems to be glassy, with a thickness about 10 μm was formed on the surface of MoSi2coating during MoSi2coating oxidized at 1200°C for 200 h. The results of the oxidation tests show that MoSi2coating prepared by air plasma spraying may be provide a protect layer for high temperature structure material.


Author(s):  
M.A. Parker ◽  
K.E. Johnson ◽  
C. Hwang ◽  
A. Bermea

We have reported the dependence of the magnetic and recording properties of CoPtCr recording media on the thickness of the Cr underlayer. It was inferred from XRD data that grain-to-grain epitaxy of the Cr with the CoPtCr was responsible for the interaction observed between these layers. However, no cross-sectional TEM (XTEM) work was performed to confirm this inference. In this paper, we report the application of new techniques for preparing XTEM specimens from actual magnetic recording disks, and for layer-by-layer micro-diffraction with an electron probe elongated parallel to the surface of the deposited structure which elucidate the effect of the crystallographic structure of the Cr on that of the CoPtCr.XTEM specimens were prepared from magnetic recording disks by modifying a technique used to prepare semiconductor specimens. After 3mm disks were prepared per the standard XTEM procedure, these disks were then lapped using a tripod polishing device. A grid with a single 1mmx2mm hole was then glued with M-bond 610 to the polished side of the disk.


Author(s):  
M. G. Burke ◽  
M. N. Gungor ◽  
P. K. Liaw

Aluminum-based metal matrix composites offer unique combinations of high specific strength and high stiffness. The improvement in strength and stiffness is related to the particulate reinforcement and the particular matrix alloy chosen. In this way, the metal matrix composite can be tailored for specific materials applications. The microstructural characterization of metal matrix composites is thus important in the development of these materials. In this study, the structure of a p/m 2014-SiC particulate metal matrix composite has been examined after extrusion and tensile deformation.Thin-foil specimens of the 2014-20 vol.% SiCp metal matrix composite were prepared by dimpling to approximately 35 μm prior to ion-milling using a Gatan Dual Ion Mill equipped with a cold stage. These samples were then examined in a Philips 400T TEM/STEM operated at 120 kV. Two material conditions were evaluated: after extrusion (80:1); and after tensile deformation at 250°C.


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