Fabrication of ZrO2/Ni and ZrO2/Al2O3 Functionally Graded Materials by Explosive Powder Consolidation Technique

Abstract

Functional gradient materials characterized by the materials having continuously varying material property from one surface to the other, have been prepared via several methods such as CVD, PVD, ion plating, plasma spraying, sintering and self-propagating high temperatures synthesis. Shock consolidation is known as a technique to produce the bulk materials from powders. However, it was hitherto difficult to obtain sound specimens without any cracks and/or central hole by using an axisymmetric explosive consolidation technique. The authors have so far developed the dynamic consolidation of difficult-to-consolidate powders such as ZrO2 and Si3N4 ceramic powders, utilizing underwater-shock wave generated by the detonation of explosive as a pressure medium of water. And they have reported that sound specimens can be fabricated without using any sintering additives. The advantages of the shock consolidation are that the compact with full density can be fabricated within nano second order and lots of defect induced and fresh surface exposed by shock pressure can reduce the post-sintering temperature in comparison with the conventional process. The purpose of the present study is to establish the technique for fabricating two kinds of FGMs, i.e. ZrO2/Ni with 10 layers and ZrO2/Al2O3 systems with 5 layers and to investigate microstructures and thermo-mechanical properties.