Synthesis of molybdenum disilicide by mechanical alloying

Abstract

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Development of MoSi2-SiC Component for Satellite Launch Vehicle

“…The high energy state of MM powder and formation of liquid phase due to melting of Si caused lower sintering temperature and shorter time to achieve near theoretical density in the VHP process. The similar observation has been noticed by Schwarz et al [12] for hot pressing of MoSi 2 powder made in high energy Spax mill. …”

Synthesis of dense nanometric MoSi2 through mechanical and field activation

“…The reduction in the intensity of the Si peaks with milling is in agreement with previous observations. 6,7 It was suggested that the reduction is the consequence of the dissolution of Si in Mo or the formation of the silicide phase. The fact that in our study no such observation was made on Si powders milled separately would lend support for the proposed explanation.…”

“…The value of B(g) was determined from the diffraction profile of a strain-free, wellannealed, coarse-grained specimen of LaB 6 . As suggested in the literature, 22 the variation of B(g) versus was obtained by fitting the measured breadth of the diffraction peaks of the standard material, using the following polynomial function:…”

“…In view of the nonequilibrium state of the nanomaterials and the fact that consolidation takes place at high temperatures and requires relatively long holding times, grain growth (Oswald ripening) is anticipated. In the cited study of Schwarz et al, 6 the grain size increased from a range of 10-15 nm to 3-10 m during the 20-30 min of densification by hot-pressing with 12 MPa at 1500°C. As was pointed out above, the relatively limited number of experimental data on mechanical and plastic properties on nanomaterials has been attributed to the difficulty of synthesizing dense bodies.…”

“…In these investigations, two types of mills were employed: SPEX and planetary mills. Using the former type, Schwarz et al 6 reported the formation of MoSi 2 after 20 h of milling under an unspecified condition of charge ratio (CR), i.e., ball/power mass ratio. But even after this time, unreacted Mo was still observed.…”