Microsc. Microanal. Microstruct. 8, 379-391 (1997)
DOI: 10.1051/mmm:1997129

Bimetallic PdCu and PdCu₃ Particles Prepared by Wet Impregnation-HRTEM Study of the Structure and the Interface with the MgO Substrate

Suzanne Giorgio et Claude Henry

CRMC2 , CNRS, Campus de Luminy Case 913, 13288 Marseille Cedex 9, France

Abstract
Bimetallic particles of PdCu and PdCu₃ are prepared by decomposition of orga-nometallic compounds on MgO micro-cubes. During the annealing between 350 and 400 °C, in reducing atmosphere, PdCu particles grow with the fcc structure, without defined shape. The particles epitaxially (001) oriented on MgO are dilated and accommodated to the substrate. After annealing at 450 °C, the particles adopt the ordered structure. The particles are limited at the edges by (100) and (110) faces. Most of them are oriented (001) on MgO with [110]PdCu_||[100]MgO, which corresponds to a perfect accommodation of the lattices without deformation compared to the bulk, despite of the reduction in H₂. The PdCu₃ particles smaller than about 10 nm were found with the ordered structure, without periodic anti-phase boundaries.

PACS
8120G - Preparation of metals and alloys compacts, pseudoalloys.
8120E - Powder techniques, compaction and sintering.
6848 - Solid solid interfaces.
8140G - Other heat and thermomechanical treatments.
6480G - Microstructure.

Key words
annealing -- copper alloys -- interface structure -- magnesium compounds -- materials preparation -- palladium alloys -- powder metallurgy -- transmission electron microscopy -- bimetallic particles -- wet impregnation -- HRTEM -- MgO substrate -- MgO micro cubes -- annealing -- FCC structure -- epitaxially 001 oriented particles -- beta ordered structure -- alpha ordered structure -- 350 to 400 degC -- PdCu MgO -- MgO -- PdCu sub 3 MgO


© EDP Sciences 1997