Migration through a martensitic stainless steel which was coated with an amorphous SiC film was studied, at temperatures ranging from 480 to 550K, using an inlet pressure of 200kPa. It was found that a thin amorphous SiC coating acted as an efficient barrier to H2 permeation. Chemical reactions occurred between migrating H and free C atoms in the SiC layers, with the formation of hydrocarbon compounds. Implantation with N improved the SiC barrier performance (table 154).

R.Checchetto, L.M.Gratton, A.Miotello: Journal of Physics D, 1994, 27[8], 1687-90

 

 

 

Table 154

Permeation of H2 through SiC

 

Sample

Temperature (K)

H2 Flux (mol/cm2s)

s

485

5.0 x 10-10

s/SiC

485

1.8 x 10-10

s/SiC*

485

0

s

515

1.3 x 10-9

s/SiC

515

4.1 x 10-10

s/SiC*

515

5.9 x 10-11

s

545

2.7 x 10-9

s/SiC

545

6.8 x 10-10

s/SiC*

545

3.9 x 10-10

* Implanted with N+