It was shown that a reduction in D permeation through AISI316L stainless steel could be achieved by depositing a (Al,Ti)N coating. A 1.7µm-thick coating could reduce the D permeation flux by a factor of 100 to 1000 at 473 to 873K (figure 1). This was attributed to the very low diffusivity of migrating D-species in the nitride. In this temperature range, the D diffusion coefficient was of the order of 10–12 to 10–11cm2/s; with an activation energy as low as 0.37eV. This activation energy could be related to the defect microstructure of the sample.

High Temperature Efficient Deuterium Permeation and Oxidation (Al,Ti)N Barriers Deposited on Stainless Steel. N.Bazzanella, R.Checchetto, A.Miotello, B.Patton, A.N.Kale, D.C.Kothari: Applied Physics Letters, 2002, 81[20], 3762-4

Figure 1

Permeation Data for D in (Al,Ti)N Layer

(yielding an activation energy for diffusion of 0.37eV)