Fig. 6 presents the SEM images of the cross section and top
surface of the membrane Pde1.0 and Pde3.3 with a thickness
of 1.0 mm and 3.3 mm, respectively.
The segmentation and separation of the substrate shown in Fig. 6 A1 was causedduring the preparation of the samples.
A dense and defectfree separation layer was obtained for both membranes, as
shown in Fig. 6 A2 and B2.
The integrity of the membrane was further proven by a gas tightness test , in which the presence
of any pinholes could be easily detected.
Furthermore, the membrane stability at elevated temperatures was verified
before (Ar, 450 C and 200 KPa) and after (Ar, 450 C and 165 KPa) hydrogen permeation test.
The excellent integrity of the membranes is mainly due to the uniform pack-pore network of the thin outer sponge-like layer (Fig. 3).