Molybdenum disilicide coating on steel and its oxidation resistance

1982 ◽  
Vol 1 (1) ◽  
pp. 19-22 ◽  
Author(s):  
Seiji Motojima ◽  
Akiyoshi Fujimoto ◽  
Kohzo Sugiyama
Keyword(s):  
Oxidation Resistance ◽  
Molybdenum Disilicide ◽  
Molybdenum Disilicide Coating

Phase transformation and layer evolution in molybdenum disilicide-silicon carbide nanolayered coatings

1994 ◽  
Vol 52 ◽  
pp. 538-539
Author(s):  
H. Kung ◽  
T. R. Jervis ◽  
J.-P. Hirvonen ◽  
M. Nastasi ◽  
T. E. Mitchell ◽  
...  
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Oxidation Resistance ◽  
Elevated Temperatures ◽  
Matrix Material ◽  
Molybdenum Disilicide ◽  
High Temperature Strength ◽  
Cross Sectional ◽  
Good Oxidation Resistance ◽  
Structural Applications

MoSi2 is a potential matrix material for high temperature structural composites due to its high melting temperature and good oxidation resistance at elevated temperatures. The two major drawbacksfor structural applications are inadequate high temperature strength and poor low temperature ductility. The search for appropriate composite additions has been the focus of extensive investigations in recent years. The addition of SiC in a nanolayered configuration was shown to exhibit superior oxidation resistance and significant hardness increase through annealing at 500°C. One potential application of MoSi2- SiC multilayers is for high temperature coatings, where structural stability ofthe layering is of major concern. In this study, we have systematically investigated both the evolution of phases and the stability of layers by varying the heat treating conditions.Alternating layers of MoSi2 and SiC were synthesized by DC-magnetron and rf-diode sputtering respectively. Cross-sectional transmission electron microscopy (XTEM) was used to examine three distinct reactions in the specimens when exposed to different annealing conditions: crystallization and phase transformation of MoSi2, crystallization of SiC, and spheroidization of the layer structures.

Microstructure and Oxidation Behavior of Molybdenum Disilicide Coating Prepared by Air Plasma Sprayed

2011 ◽  
Vol 686 ◽  
pp. 583-588 ◽  
Author(s):  
Jian Hui Yan ◽  
Si Wen Tang ◽  
Jian Guang Xu
Keyword(s):  
Plasma Spraying ◽  
Gas Turbines ◽  
Hexagonal Lattice ◽  
Molybdenum Disilicide ◽  
Temperature Structure ◽  
Air Plasma ◽  
Air Plasma Spraying ◽  
Plasma Sprayed ◽  
Molybdenum Disilicide Coating ◽  
Oxidation Behaviors

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.

Mechanically Activated Combustion Synthesis of Molybdenum Silicides and Borosilicides

2014 ◽  
Vol 1760 ◽  
Author(s):  
Mohammad S. Alam ◽  
Alan A. Esparza ◽  
Evgeny Shafirovich
Keyword(s):  
Mechanical Properties ◽  
Oxidation Resistance ◽  
Power Plants ◽  
Exothermic Reaction ◽  
Molybdenum Disilicide ◽  
Combustion Products ◽  
Shs Compaction ◽  
Molybdenum Silicides ◽  
High Oxidation ◽  
High Oxidation Resistance

ABSTRACTMolybdenum silicides and borosilicides are promising structural materials for advanced power plants. A major challenge, however, is to simultaneously achieve high oxidation resistance and acceptable mechanical properties at high temperatures. For example, molybdenum disilicide (MoSi2) has excellent oxidation resistance and poor mechanical properties, while Mo-rich silicides such as Mo5Si3 (called T1) have much better mechanical properties but poor oxidation resistance. One approach is based on the fabrication of MoSi2−T1 composites that combine high oxidation resistance of MoSi2 and good mechanical properties of T1. Another approach involves the addition of boron to Mo-rich silicides for improving their oxidation resistance through the formation of a borosilicate surface layer. In particular, Mo5SiB2 (called T2) phase and alloys based on this phase are promising materials.In the present paper, MoSi2−T1 composites and materials based on T2 phase are obtained by mechanically activated self-propagating high-temperature synthesis (MASHS). To obtain denser products, the so-called SHS compaction (quasi-isostatic pressing of hot combustion products) has been employed. Thermal analysis has shown that SHS compaction significantly improves the oxidation resistance. Self-sustained combustion of Mo/Si/B mixtures for the formation of T2 phase becomes possible if the composition is designed for adding a more exothermic reaction of MoB formation. These mixtures exhibit spin combustion. Oxidation resistance of the obtained multi-phase Mo−Si−B materials is independent on the concentration of Mo phase in the products. The “chemical oven” technique has been used to obtain a single Mo5SiB2 phase and an alloy consisting of α-Mo, Mo5SiB2, and Mo3Si phases.

Role of Silica in the Oxidation Resistance of Molybdenum Disilicide

Nature ◽  
1964 ◽  
Vol 203 (4948) ◽  
pp. 967-969 ◽  
Author(s):  
GEORGE TODD ◽  
ERIC PARRY
Keyword(s):  
Oxidation Resistance ◽  
Molybdenum Disilicide
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