CHEM02200704003 Nilamadhab Pandhy - Homi Bhabha National ...

Chapter 3
S =
(2)
= S n + S e (3)
Where S n and S e are the energy loss due to nuclear and electronic stopping power. From
the stopping power (S) the projected range (R p ) of the ions with initial energy E 0 inside the target
can be estimated using Eq. (4) [57].
R p =
(4)
In the present investigation, to study the effect of sub-surface modification on the corrosion
resistance of 304L SS, nitrogen ion implantation was carried out at 70 keV energy by 150 keV
accelerator at room temperature using 99.999 % high purity nitrogen on 12 mm diameter
specimens of 304L SS. The doses given were in the range of 1×10 15 , 1×10 16 , 1×10 17 and 2.5×10 17
N + /cm 2 , respectively (Eq. 1). The vacuum in the target side during implantation was maintained at
1×10 -5 Pa. The projected range of the ions in 304L SS was calculated using Monte-Carlo
simulation code Transport of Ions in Matters (TRIM) [57]. TRIM is based upon binary ion-atom
collision approximation assuming moving atom as ion and the target atom as atoms for calculating
the range distribution of ions inside the target. The Monte-Carlo simulation as applied in TRIM
has number of advantages over analytic formulation. It allows rigorous treatment of elastic
scattering, explicit consideration of surface and interfaces leading to easy determination of
projected range and distribution of particles.
3.1.2.2 Magnetron sputtering
Magnetron sputtering is a high vacuum coating process for depositing metals, alloys and
ceramic coatings. Developed in 1970’s, magnetron sputtering is finding increasing application in