High pressure (explosive) consolidation of n-Al2O3-ceramics

Nano-materials are prospective materials for engineering applications. They are called nano-materials as their grain size is in the range of nanometers. It is very difficult to retain this small grain size during conventional consolidation of powders and subsequent sinter processes. A key to solve this problem seems to be explosive consolidation, as explosives develop shock pressures up to about 30GPa. Experiments with a nano-Al2O3-powder, which was produced by the exploding wire technique and which revealed a mean particle size of about 60 nm showed, that almost 100 per cent of crystalline density is achievable by explosive consolidation. The method of explosive consolidation and the results are reported. Materials analysis also includes SEM- and XRD-Analysis. It is found that phase transitions occur and as a result of high shock wave treatment X-Ray line decrease or broadening occurs. The retention of original grain size in the compact can be evaluated by Hall-Williams investigations .