164 Prakt. Met. Sonderband 38 (2006) 
pha: 
Polished samples were dismounted from the resin before being attached to the sample diffe 
holder with a conductive carbon tape. Before placing into the FIB/SEM chamber, all samples grail 
were cleaned with alcohol in an ultrasonic cleaner. dent 
All presented micrographs in this work are ion induced secondary electron images (IISE diffe 
images). The only exception is Fig. 4a, which is an electron induced secondary electron one 
image (SE image). None of the presented images was electronically edited. dian 
have 
3 RESULTS AND DISCUSSION 
Surfaces and cross-sections 
Fig. 1a shows the mechanically polished cross-section of an alloy 1 ribbon with six 
sum x Sum ion-etched fields. In the same way the as-cast free (upper) surface of an alloy 1 
ribbon was FIB-treated. The results are shown in Fig. 1b. Etching current and etching times 
are indicated. The contrast of etched fields increases proportionally with the etching time. 
The microstructure is fully martensitic. The contrast between different plates is due to their 
different crystallographic orientation. Darker plates have low index directions almost parallel 
to the ion beam. This also means that plates with the same level of greyness have 
approximately the same orientation to the beam. It seems that in brighter regions the 
sputtering rate is much higher than elsewhere. In these plates very soon columns developed 
that are typical FIB-artefact. Within other plates, which appeared uniform at the beginning of 
etching, a structure consisting of finer lamellae became visible. By comparing Fig. 1a and . 
Fig. 1b it is also obvious that the etching effect is much stronger on smoother polished 
samples than on the unprepared free surface of the ribbon. However, the surface must be 
clean, without dust or other particles since these particles prevent uniform etching of the Figı 
surface. 
' OA Ch 
| | By 
Figure 1: lon etched alloy 1 (Cu — 13 wt% Al — 4 wt% Ni) melt-spun ribbon; a) Mechanically 
polished cross-section; b) Free (upper) surface of the ribbon. not pre-treated. Fig 
Fig. 2 shows images of alloy 2; a mechanically polished cross-section in Fig. 2a and after 
1 hour FIB-etching with 10 pA in Fig. 2b. As one can anticipate from Fig. 2a, the ribbon 
consists of two phases. However, the contrast is very low. After FIB-etching the two