Effect of sintering pressure on hot press sintering of 17Ni/(10NiO–NiFe₂O₄) cermet

Abstract

The sintering behaviour of 17Ni/(10NiO–NiFe₂O₄) cermet not only is influenced by the characteristics and impurities of the raw materials but also is dependent on extra pressure during the fabrication process. Our work was concerned with the effect of sintering pressure on the relative density, mechanical properties and electrical conductivity of 17Ni/(10NiO–NiFe₂O₄) cermet. The nickel–ferrite based cermet was prepared by hot press sintering technology at 1100°C for 120 min, and sintered at pressures ranging from 12 to 24 MPa. The microstructure, phase compositions and mechanical properties were studied by scanning electron microscopy, X-ray diffraction and three-point bending strength tests respectively. It was found that the relative density and bending strength of NiFe₂O₄ based cermet have a great influence upon the sintering pressure, and that the highest bending strength of 125·89 MPa could be obtained under a sintering pressure of 16 MPa. Meanwhile, it was shown that thermal shock resistance decreased as the sintering pressure increased.

Keywords:

• Hot press sintering
• NiFe₂O₄ based cermet
• Mechanical properties
• Sintering pressure

Acknowledgements

The authors would like to express their gratitude for the financial support provided by the international cooperation project of the Ministry of Science and Technology, China (grant no. 2010DFA52130 and 2012DFG70640).