In:
International Journal of Materials Research, Walter de Gruyter GmbH, Vol. 99, No. 4 ( 2008-04-01), p. 352-358
Abstract:
In this work, MoSi 2 – ZrO 2 -composites with different volume fractions (15-, 25-, 35 vol.% ZrO 2 ) were examined. Zirconium oxide was successfully tetragonal stabilised (metastable state) through a high temperature isostatic pressure process, where the tetragonal – monoclinic phase transformation is inhibited by the pressure of the MoSi 2 -matrix. Stabilisers, e. g. Y 2 O 3 were not used. Increasing ZrO 2 content enhances strength and fracture toughness at room temperature. For temperatures above 900°C up to 1500°C no influence of the volume fraction of ZrO 2 was observed with respect to the compression tests. Wear of pre-oxidised samples (20 min at 1000°C) is higher for the 25 and 35 vol.% than non-oxidised material. Oxidation resistance is observed to be poor and decreases with increasing ZrO 2 content in the composite. Early crack initiation leads to poor creep behaviour and thermo-shock behaviour. This is probably due to the oxygen diffusing through the ZrO 2 -particles. Consequently no continuous protective SiO 2 -layer can be built as known from pure MoSi 2 -materials. In general the investigated material is not suitable for high temperature applications because of the poor oxidation behaviour.
Type of Medium:
Online Resource
ISSN:
2195-8556
,
1862-5282
Language:
English
Publisher:
Walter de Gruyter GmbH
Publication Date:
2008
detail.hit.zdb_id:
2232675-3
detail.hit.zdb_id:
2128058-7
detail.hit.zdb_id:
203021-4
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