Sintering, thermal stability and mechanical properties of ZrO₂-WC composites obtained by pulsed electric current sintering

Abstract

ZrO₂-WC composites exhibit comparable mechanical properties as traditional WC-Co materials, which provides an opportunity to partially replace WC-Co for some applications. In this study, 2 mol.% Y₂O₃ stabilized ZrO₂ composites with 40 vol.% WC were consolidated in the 1150°C–1850°C range under a pressure of 60 MPa by pulsed electric current sintering (PECS). The densification behavior, microstructure and phase constitution of the composites were investigated to clarify the role of the sintering temperature on the grain growth, mechanical properties and thermal stability of ZrO₂ and WC components. Analysis results indicated that the composites sintered at 1350°C and 1450°C exhibited the highest tetragonal ZrO₂ phase transformability, maximum toughness, and hardness and an optimal flexural strength. Chemical reaction of ZrO₂ and C, originating from the graphite die, was detected in the composite PECS for 20 min at 1850°C in vacuum.

Keywords

ceramic composite / pulsed electric current sintering (PECS) / grain size / mechanical property

References

[1] Anné G, Put S, Vanmeensel K, . Hard, tough and strong ZrO₂-WC composites from nanosized powders. Journal of the European Ceramic Society , 2005, 25(1): 55–63 10.1016/j.jeurceramsoc.2004.01.015
[2] Jiang D, Van der Biest O, Vleugels J. ZrO₂-WC nanocomposites with superior properties. Journal of the European Ceramic Society , 2007, 27(2–3): 1247–1251 10.1016/j.jeurceramsoc.2006.05.028
[3] Huang S G, Vanmeensel K, Van der Biest O, . Development of ZrO₂-WC composites by pulsed electric current sintering. Journal of the European Ceramic Society , 2007, 27(10): 3269–3275 10.1016/j.jeurceramsoc.2006.11.079
[4] Basu B, Lee J H, Kim D Y. Development of WC-ZrO₂ nanocomposites by spark plasma sintering. Journal of the American Ceramic Society , 2004, 87(2): 317–319 10.1111/j.1551-2916.2004.00317.x
[5] Malek O J A, Lauwers B, Perez Y, . Processing of ultrafine ZrO₂ toughened WC composites. Journal of the European Ceramic Society , 2009, 29(16): 3371–3378 10.1016/j.jeurceramsoc.2009.07.013
[6] Vanmeensel K, Laptev A, Hennicke J, . Modelling of the temperature distribution during field assisted sintering. Acta Materialia , 2005, 53(16): 4379–4388 10.1016/j.actamat.2005.05.042
[7] Vanmeensel K, Laptev A, Van der Biest O, . The influence of percolation during pulsed electric current sintering of ZrO₂-TiN powder compacts with varying TiN content. Acta Materialia , 2007, 55(5): 1801–1811 10.1016/j.actamat.2006.10.042
[8] Anstis G R, Chantikul P, Lawn B R, . A critical evaluation of indentation techniques for measuring fracture toughness: I. Direct crack measurements. Journal of the American Ceramic Society , 1981, 64(9): 533–538 10.1111/j.1151-2916.1981.tb10320.x
[9] ASTM Standard E 1876–99, Test method for dynamic Young’s modulus, shear modulus, and Poisson’s ratio for advanced ceramics by impulse excitation of vibration. ASTM Annual Book of Standards, Philadelphia, PA , 1994
[10] Lange F F. Transformation-toughened ZrO₂ correlations between grain size control and composition in the system ZrO₂-Y₂O₃. Journal of the American Ceramic Society , 1986, 69(3): 240–242 10.1111/j.1151-2916.1986.tb07416.x
[11] Basu B, Vleugels J, Van der Biest O. Toughness tailoring of yttria-doped zirconia ceramics. Materials Science and Engineering A , 2004, 380(1–2): 215–221 10.1016/j.msea.2004.03.065
[12] Chamberlain A L, Fahrenholtz W G, Hilmas G E. Pressureless sintering of zirconium diboride. Journal of the American Ceramic Society , 2006, 89(2): 450–456 10.1111/j.1551-2916.2005.00739.x
[13] Moska?a N, Pyda W. Thermal stability of tungsten carbide in 7mol.% calcia-zirconia solid solution matrix heat treated in argon. Journal of the European Ceramic Society , 2006, 26(16): 3845–3851 10.1016/j.jeurceramsoc.2005.12.012
[14] Toraya H, Yoshimura M, Somiya S. Calibration curve for quantitative analysis of the monoclinic-tetragonal ZrO₂ system by X-ray diffraction. Journal of the American Ceramic Society , 1984, 67: C119–C121