Eur. Phys. J. AP 16, 167-173 (2001)
https://doi.org/10.1051/epjap:2001206

Influence of tabletting pressure upon internal morphology of a Fe₂O₃Cr₂O₃ catalyst

University of Craiova, A.I. Cuza 13, 1100 Craiova, Romania

Corresponding author: protaru@central.ucv.ro

Received: 30 March 2001
Revised: 9 July 2001
Accepted: 9 July 2001
Published online: 15 December 2001

Abstract

A study on the influence of tabletting pressure upon the internal morphology of Fe₂O₃-Cr₂O₃ catalytic system shows the behaviour of that system at crystallite level or even below it. On increasing tabletting pressure of catalytic powder, remanent stresses are left in the tablets formed which can be calculated in terms of the remanent strain. The macrostresses are constant and small at tabletting pressures ranging within 10⁸ − 5 × 10⁸ Pa and increase linearly between 6 × 10⁸ and 14 × 10⁸ Pa. The microstresses take measurable values only in samples tabletted at pressures higher than 7 × 10⁸ Pa. Besides the formation of remanent stresses, the increase of tabletting pressure brings about the overall change of porous structure and mechanical resistance of the catalytic system. The remanent stresses that appeared at tabletting result in cracks along some planes which, in most instances, are parallel to the planar faces of tablets. The maximum acceptable tabletting pressure of the catalytic system studied amounts to 5 × 10⁸ Pa.