CHEM02200704003 Nilamadhab Pandhy - Homi Bhabha National ...

Chapter 3
3.1.1.2 Specimen preparation
The size of the specimen prepared for the whole investigation varies depending upon the
suitability and requirement of the particular experimental technique. Mostly, the specimens are
either of square type of size 1 cm × 1cm × 1.5 cm or of circular of size of 12 mm diameter.
Specimens of the aforementioned size were cut from the sheet or rod, mechanically grinded using
emery paper (SiC) up to 1200 grade, and then finely polished in 0.25 µ diamond paste. All the
specimens are cleaned with acetone, and then ultrasonically in double distilled water prior to any
surface modification or electrochemical investigations.
3.1.1.3 Solution preparation
The test solution for corrosion study was nitric acid. The solution used for different type of
electrochemical corrosion investigation varies from dilute to concentrated medium depending
upon the requirement of the test, and the equipment used for the investigation. The nitric acid
solutions were prepared from Ranbaxy make analytical grade chemical reagent of specific gravity
1.41, and maximum permissible impurity was around 0.00005 %.
3.1.2 Surface modification techniques
3.1.2.1 Ion implantation
Ion implantation using accelerator is one of the important surface modification techniques
in the field of corrosion science for different type of engineering materials. It has been found that
by doping metallic surfaces with suitable elements by ion implantation technique the rate of
anodic reaction is lowered significantly [49,50]. Due to this, the technique is fast developing as a
research tool in the corrosion study of conventional and non-conventional alloys. Ions of almost
any atom species can be implanted, but nitrogen is generally implanted to improve corrosion
resistance, and tribological properties of austenitic stainless steel, and is already commercialized in
an expanding scale. The large scale use of nitrogen is because, (1) it stabilizes the austenite