Cyclic oxidation behaviors of MoSi₂ with different relative density

Abstract

The influence of different relative density on the cyclic oxidation behaviors of MoSi₂ at 1 273 K were studied. “Pesting” was not found in all MoSi₂ materials after being oxidized for 480 h. All samples exhibited continuous mass gain during the oxidation process. The mass gains of MoSi₂ with the lowest relative density (78.6%) and the highest relative density (94.8%) are increased by 8.15 mg·cm⁻² and 3.48 mg·cm⁻², respectively. The surface of the material with lower relative density formed a loose, porous and discontinuous oxidation scale, which accelerated oxygen diffusion and aggravated the oxidation process. However, a dense scale in the material with higher relative density is formed, which acts a diffusion barrier to the oxygen atoms penetrating into the matrix. The high temperature oxidation resistance of MoSi₂ can be improved by increasing its relative density.

Keywords

molybdenum disilicide / relative density / cyclic oxidation

References

[1] Vasudevan A. K., Petrovic J. J. A Comparative Overview of Molybdenum Disilicide Composites[J]. Mater. Sci. Eng., 1992, A155: 1-17.

[2] Kurokawa K., Houzumi H., Saeki I. Low Temperature Oxidation of Full Dense and Porous MoSi₂[J]. Mater. Sci. Eng., 1999, A261: 292-299.

[3] Lohfeld S., Schtze M. Oxidation Behavior of Particle Reinforced MoSi₂ Composites at Temperature up to 1 700 Part °C: I Literature Review[J]. Materials and Corrosion, 2005, 56(2): 93-97.

[4] Lohfeld S., Schtze M. Oxidation Behavior of Particle Reinforced MoSi₂ Composites at Temperature up to 1 700 °C Part II: Initial Screening of the Oxidation Behaviour of MoSi₂ Composite[J]. Materials and Corrosion, 2005, 56(3): 149-158.

[5] Zhang H. A., Li S. W., Long C. G. Study of Low-temperature Oxidation Process of MoSi₂-based Composites[J]. Journal of Functional Materials, 2000, 14(1): 69-71.

[6] Kuchino Kurokawa K., Shibayama T. Effect of Microstructure on Oxidation Resistance of MoSi₂ Fabricated by Spark Plasma Sintering[J]. Vacuum, 2004, 73: 623-628.

[7] Mckamey C. G., Tortorelli P. F., Devan J. H. Study of Pest Oxidation in Polycrystalline MoSi₂[J]. J. Mater. Res., 1992, 7(10): 2 747-2 755.

[8] Hansson K., Halvarsson M., Tang J. E. Oxidation Behaviour of a MoSi₂-based Composite in Different Atmosphere in the Low Temperature Range (400–550 °C)[J]. Journal of the Ceramic Society, 2004, 24: 3 559-3 573.

[9] Natesan K., Dedvi S. C. Oxidation Behavior of Molybdenum Silicides and Their Composites[J]. Intermetallics, 2000, 8: 1 147-1 158.

[10] Berztiss D. A., Cerchiara R. R., Gulbransen E. A., . Oxidation of MoSi₂ and Ccomparison with Other Silicide Materials[J]. Mater. Sci. Eng., 1992, A155: 165-181.

[11] Bartlett R. W., Marsuoka Takahashi H. High Temperature Oxidation of Molybdenum Disilicide[J]. J. Am.Ceram. Soc., 1965, 48(11): 551-552.