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Submitted on 1 Jan 1977
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CRYSTAL MORPHOLOGY OF SMALL PARTICLES
OF ALUMINIUM AND SILVER FORMED BY
EVAPORATION IN ARGON AT LOW PRESSURE
K. Kimoto, L. Nishida
To cite this version:
JOURNAL DE PHYSIQUE Colloque C2, suppldment au no 7 , Tome 38, Juillet 1977, page C2-195
CRYSTAL MORPHOLOGY OF SMALL PARTICLES OF ALUMINIUM AND SILVER
FORMED
BY EVAPORATION
IN
ARGON AT LOW PRESSURE
K.
KIMOTO a n dI. NISHIDA
Physics Laboratory, Dept. of G e n e r a l Education, N a g o y a University, Chikusa-Ku, Nagoya
464,
J a p a nRbumk.
-
On peut produire des particules fines (des mCtaux) par Cvaporation dans un gaz iperte B basse pression. q e s particules sont bien dCfinies quand leurs tailles se situent entre cent A et quelques milliers A.Nous avons Ctendu nos Ctudes prCcCdentes, concernant la morphologie cristalline des particules fines d'Al e t d'Ag formCes dans des conditions ordinaires d'kvaporation sous vide, au domaine des particules formCes en atmosphkre d'argon trks pur au moyen d'appareils de trks haut vide.
Les particules d'Al formCes en atmosphkre pure se trouvent sous une forme cubo-octakdrique avec les bords e t les angles arrondis. 11s se forment en polykdre de Wulff cubique
B
faces centrCes, quand on ne tient compte que de l'interaction des premiers voisins, bien qu'un tel traitement soit insuffisant en apparence pour des mCtaux. Toutes les particules formkes dans les conditions ordinaires d'Cvaporation ont kt6 presque toujours de forme sphCrique et n'ont pas montrk de caractkre polykdrique.Les particules d'Ag formkes en atmosphkre pure se prksentent sous forme icosakdrique ayant, soi-disant, la structure de multi-mlcle. Cependant, le docakdre pentagonal ayant la structure sus-dite, qui est prCdominant parmi les particules d'Ag formkes dans les conditions ordinaires d'kvaporation, est trks rarement observC ; et les plaques hexagonales ou triangulaires tronqu6es; qui sont aussi souvent remarqubes parmi les particules d'Ag formkes dans les conditions ordinaires d'kvaporation, ne sont pas observ6es dans le cas de l'atmosphkre pure.
Abstract. - Fine particles of metals may be produced by evaporation in inert gas at low pressure. These particles ~how~well-defined crystal habits when the size of the particles is in the range between one hundred A and several thousand A.
We extend our previous studies [I, 21 on the crystal morphology of small particles of A1 and Ag formed in the ordinary vacuum evaporation unit to the realm of the particles formed in very clean atmosphere of argon by means of ultra-high vacuum evaporation unit.
A1 particles formed in clean atmosphere show the crystal habit of cubo-octahedron with rounded edges and corners. It is a Wulff polyhedron of f.c.c. crystal when only the first nearest neighbour interaction is taken into account despite its apparent inadequacies when applied to metals. All particles formed in the ordinary evaporation unit were always nearly spherical in shape and showed no polyhedral character.
Ag particles formed in clean atmosphere mainly occur in the form of icosahedron having the so-called multiply-twinned structure. However, the pentagonal decahedron having the MT structure which was predominant among Ag particles formed in the ordinary evaporation unit is very rarely observed ; and the hexagonal or truncated triangular plates which were also often observed among the Ag particles formed in the ordinary evaporation unit are not observed in the case of clean atmosphere.
Reference
[I] KIMOTO, K., KAMIYA, Y., NONOYAMA, M. and UYEDA, R., Japan. J . Appl. Phys. 2 (1963) 702.
121 KIMOTO, K. and MISHIDA, I.. J a ~ a n J . A D D ~ . Phvs. 6 (1967)
