190 Prakt. Met. Sonderband 38 (2006) 
The 
sem-se | | coi FIB 10pA vari 
the 
pre 
bou 
usir 
gre: 
poir 
high 
For 
don 
foct 
coa 
(cur 
2um 
Fig. 4: Microstructure of cp Ti after Ar’ ion etching revealed using SEM (left) and 
FIB (Ga ion, 10pA aperture) (right) 
From other point of view titanium after severe plastic deformation posses a high part of low 
angle grain boundaries. It can be supposed that the difference between the subgrains is so 
low, that the change in the channeling effect from grain to grain is insignificant and couldn’t 
be observed. Etching using Ar’ ions (PECS™) offers a solution. The sensitivity of the Ar" 
ion etching rate to even small changes in crystallographic orientation is considerable (Fig. 
4). Grains and subgrains of titanium, even in submicrometer range, can be clearly imaged. 
The optimum parameters for the Ar’ ion etching were 6 minutes at an angle of 45°, 
followed by 2 minutes at the angle of 0°. In the FIB process, there are some physically 
limitations in the visualization of low angle grain boundary (critical half angle for ion 
channeling). 
Fig. 5 shows the microstructure of an electrochemically deposited Ni coating after Ar" ion 
(PECS™.left) and Ga" ion etching (FIB-right). The visualizing was done using SEM and 
FIB Fig 
— I : —— A 
N Apatin- Ni-Coatinc IB 0.1n4 
To 
rec 
(PE 
wa 
ene 
4 
PE 
mic 
an 
Ie 2 um 3 ma 
Fig. 5: Microstructure of a nickel coating after Ar” ion etching revealed using SEM (left) =f 
and after Ga" ion etching, 0,1nA aperture, FIB (right)