||According to a method of
Brunauer, Emmett and Teller* the surface of a (ceramic) powder can be calculated
from the N2-isotherm, which is observed at the boiling point
of liquid nitrogen. By the analysis of the adsorption curves within the
relative pressure ranges p/p0 ~ 0,05 and p/p0
~ 0,2 the volume Vm is determined, which according to the theory
of Brunauer, Emmett and Teller corresponds to the quantity of nitrigen,
which is necessary for a monomolecular layer. The surface needed for one
nitrigen molecule is 16,2Å2. From this value the specific
surface of the sample can be determined in m2/g.
* Brunnauer, S., P.H. Emmett
und E. Teller: J. Amer. Chem. Soc. 60 (1938) 309.