Sonochemical synthesis of nanocrystalline molybdenum disilicide (MoSi2)

✍ Scribed by Timothy J. Trentler; R. Suryanarayanan; Shankar M.L. Sastry; William E. Buhro

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 351 KB
• Volume: 204
• Category: Article
• ISSN: 0921-5093
• DOI: 10.1016/0921-5093(95)09959-x

✦ Synopsis

Sonochemical co-reduction of MoC15 and SiC14 with NaK alloy in a hexane dispersion using 600 W. 20 kHz irradiation, followed by annealing at 900 °C produces nanocrystalline MoSi 2 powders with ~ 90% yield. Consolidation by hot pressing at 1170 °C, 140 MPa for 4 h gives a 78%-dense compact with 31 nm average grain sizes and a Vickers microhardness of 1484 (10% kg/mm 2. Consolidation by hot pressing at 1200 °C, 100 MPa for 10 min. followed by hot isostatic pressing at 1100 °C, 200 MPa for 4 h gives a 83%-dense compact with 41 nm average grain sizes and a Vickers microhardness of 1587 _+ 10% kg mm-2 The second compact exhibits a compressive yield strength of 2875 MPa, and fractures without significant plastic deformation. The microhardness values and compression strengths are 50-70% higher in nanocrystalline MoSi2 than in conventional, coarse-grained MoSiv