Effect of Different Sintering Processes on Microstructure of Alumina Ceramics

Abstract:

Structural ceramics, such as alumina, are widely used in industrial applications due to their properties such as hardness, chemical resistance and thermal stability in high temperatures. However, low fracture toughness has limited applications of these materials. One way to overcome the low fracture toughness is to control the microstructure, seeking a refined and homogeneous microstructure. In this way, the aim of this study was to investigate the effect of unconventional methods sintering based on two steps and microwaves sintering methods on the microstructure of a commercial alumina ceramic. From two-steps sintering method, the samples are first heated to a high temperature and then cooled down to a lower than one temperature to suppress grain-boundary migration. Ceramics obtained by microwave sintering method were produced after 1100, 1300 and 1350°C for 1 hour. The microwave heating method reduces the time and temperature processing, which results in energy saving. The sintered samples were characterized by apparent density, scanning electron microscopy and measurements of grain size. The results showed that two-steps sintering and microwave were effective to control the microstructure of alumina and that in two steps sintering it is essential to control the sintering steps to inhibit grain growth.

• Periodical: Advances in Science and Technology (Volume 87)
• Pages: 145-150
• DOI: https://doi.org/10.4028/www.scientific.net/AST.87.145
• Online since: October 2014
• Authors: Adriana Scoton Antonio Chinelatto, Christiane Lago Ojaime, Maria Virgínia Gelfuso, Daniel Thomazini, Adilson Luiz Chinelatto
• Keywords: Alumina, Microwave, Two Steps Sintering

References

[1] R. J. Brook, Fabrication principles for the production of ceramics with superior mechanical properties Proc. BR. Ceram. Soc. 32 (1982) 7-24.

[2] F. J. T Lin, L. C. DeJonghe, Microstructure refinement of sintered alumina by two-step sintering technique, J. Am. Ceram. Soc. 80 (1997) 2269-2277.

DOI: 10.1111/j.1151-2916.1997.tb03117.x

[3] M-Y Chu, F. Lin, L. C DeJonghe, Initial Coarsening and microstructural evolution of fast-fired and MgO-doped alumina, J. Am. Ceram. Soc. 80 (1997) 2891-2896.

[4] I-W Chen, X. H. Wang, Sintering dense nanocrystalline ceramics without final-stage grain growth Nature, 404 (2000) 168-171.

DOI: 10.1038/35004548

[5] J. LI, Y. YE Densification and grain growth of Al2O3 nanoceramics during pressureless sintering, J. Am. Ceram. Soc. 89 (2006) 139-143.

DOI: 10.1111/j.1551-2916.2005.00654.x

[6] F. ZUO, C. CARRY, S. SAUNIER, S. MARINEL, D. GOEURIOT Comparison of the Microwave and Conventional Sintering of Alumina: Effect of MgO Doping and Particle Size, J. Am. Ceram. Soc. 96 (2013) 1732–1737.

DOI: 10.1111/jace.12320

[7] M. Oghbaei, O. Mirzaee, Microwave versus Conventional Sintering: A Review of Fundamentals, Advantages and Applications, J. Alloy. Compd. 494 (2010) 175–189.

DOI: 10.1016/j.jallcom.2010.01.068

[8] D. Grossin, S. Marinel, J. G. Noudem, Materials Processed by Indirect Microwave Heating in a Single-Mode Cavity, Ceram. Int., 32 (2006) 911–915.

DOI: 10.1016/j.ceramint.2005.06.017

[9] F. Zuo, C. Carry, S. Saunier, S. Marinel, D. Goeuriot, Comparison of the Microwave and Conventional Sintering of Alumina: Effect of MgO Doping and Particle Size, J. Am. Ceram. Soc., 96 (2013) 1732–1737.

DOI: 10.1111/jace.12320

[10] K. I. Rybakov, V. E. Semenov, Possibility of Plastic Deformation of an Ionic Crystal due to the Nonthermal Influence of a High-Frequency Electric Field, Phys. Rev. B, 49 (1994) 64–68.

DOI: 10.1103/physrevb.49.64

[11] J. X. Wang, J. Binner, Y. X. Pang, B. Vaidhyanathan, Microwave-Enhanced Densification of Sol–Gel Alumina Films, " Thin Solid Films, 516 (2008) 5996–6001.

DOI: 10.1016/j.tsf.2007.10.095