Mechano-chemical Effects of One-dimensional Explosive Shock Treatment on the Characteristics of Si3N4 [Translated]†

Abstract

Direct consolidation of α- and β-Si3N4 is conducted by the use of one-dimensional explosive shock treatment. The effect of shock pressure, phase and particle size distribution of a sample powder on the characteristics of the explosively shocked compact is examined by the measurement with X-ray diffraction (XRD), Electron spin resonance (ESR), and Infrared absorption (IR) among others. The following are the results: 1) Cracks exist in the shock compact. The apparent density and Vickers hardness increase with the increase in shock pressure. A compact of ca. 90% theoretical density is obtained. 2) Residual strain by XRD and spin density by ESR are reduced under higher shock pressures. This is considered to be attributed to the relaxation effect of high residual temperature. The shock compact of α-Si3N4 receives more residual strain and spin density than that of β-Si3N4. 3) The effect of particle size distribution of the sample powder on the characteristics of the shock compact is slight. The shock compact of larger particle size has more residual strain. 4) Metal impurities are not found except in the surface layer of the compact. 5) The solubility of the powder grinding shock compact in 1N-NaOH is higher than that of the as-received powder. This indicates that an active surface layer exists in the shock compact. 6) The tapping density of the powder grinding shock compact is much higher than that of the as-received powder.† This report was originally printed in J. Soc. Powder Technology, Japan, 23(4), 250-257 (1986) in Japanese, before being translated into English by KONA Editorial Committee with the permission of the editorial committee of the Soc. Powder Technology, Japan.