Kelvin Equation With Broekhoff-De Boer Thickness Curve - Micromeritics ASAP 2460 Operator's Manual

Appendix F

Kelvin Equation with Broekhoff-de Boer Thickness Curve

N2 - Broekhoff-de Boer Model
Geometry
Substrate
Category:
Method:
The kernel function is calculated using the Broekhoff-de Boer equation with standard parameters:
log
The nitrogen properties used in the Kelvin equation are:
Surface tension =
Molar density =
N2 - Broekhoff-de Boer Model
Geometry
Substrate
Category:
Method:
The calculation is similar to the above except that cylindrical geometry is assumed, and the film thick-
ness depends on pore size (see reference).
Reference:
F-16
Slit
Average
Porosity
Nitrogen at 77 K
– 16.11
0 – 0.1137
 
--------------- -
p/p = + 0.1682
2
t
8.88 dynes cm
0.02887 g cm
Cylinder
Average
Porosity
Nitrogen at 77 K
Specifically, equations 20 and 21 in: J.C.P. Broekhoff and J.H. de Boer,
"The Surface Area in Intermediate Pores," Proceedings of the
International Symposium on Surface Area Determination, D.H. Everett,
R.H. Ottwill, eds., U.K. (1969).
t
-1
-3
ASAP 2460 Operator's Manual
246-42800-01 - Aug 2013