01716naa a2200241 a 450000100080000000500110000800800410001910000180006024501070007826000090018552010400019465000280123465000140126265000180127665000090129465000090130365300080131265300350132065300220135570000230137770000170140077300570141710246322003-04-28       2002    bl ---       0--  u    #d1 aVAZ, C. M. P.  aThickness and size distribution of clay-sized soil particles measured through atomic force microscopy.  c2002  aSoil particle size distribution is a very important soil characterisitc because it is related with many physical, chemical and biological  processes occurring in soils. However, at the sub-micron range, where many important sorption and transformations processes occur, there are scanning electron microscopy (SEM_. The classical TEM and SEM, however, are sometimes unable to clearly differente between agglomerantes, particles and grains, and sample preparation is very difficult and tedious. To overcome these limitations, we have aplied the atomic force microscopy (AFM) technique to analyse the particle size distribution of an oxisol from São Carlos site, in Brazil, at the sub-micron range. Thicness and diameter of soil particles deposited in freshly, cleaved mica were measured for each individual particle, allowing to determine their particle size distribution. Assuming cylindrical shaped particles and a constant aprticle density of 2.7 gcm-3, the mass=based soil particle distribution at the sub-micron range is obtained.  aatomic force microscopy  akaolinite  aparticle size  asoil  aSolo  aAFM  aMicroscopia de força atômica  aParticle tichness1 aHERRMANN, P. S. P.1 aCRESTANA, S.  tPowder Technology, Lausannegv. 126, p. 51-58, 2002.