Biomedical Engineering Reference
In-Depth Information
FIGURE 18.10
AES spectra are shown for (A) as-received Ti and (B) after pretreatment in NaOH
[68]
.
contamination layers on the sample surface
[34]
. Scanning Auger microscopy (SAM) allows surfaces
to be mapped for one selected element at a time. In this mode, the electron beam is scanned over a
selected area. The Auger intensity is measured at each point of the area
[65-67]
. SAM requires higher
beam currents and is much slower than SEM/EDX
[34]
.
18.3.4.1 AES Case Studies
Pisarek et al.
[68]
used AES to investigate chemical and morphological changes to the surface of tita-
nium following exposure to acidic or alkaline solutions. Control of these exposures may increase the
effective surface area of the Ti, and thus the biocompatibility. Auger electron microanalysis enabled
subtle changes in the modified Ti surface layer to be examined, in terms of local chemical composi-
tion. SEM images and AES spectra are shown in
Figure 18.10
for (A) as-received Ti and (B) after
pretreatment in NaOH.
Immersion in 5 M NaOH and subsequent heating up to 600°C results in a porous, “honeycomb”
morphology. In terms of the Auger spectra, the signals from Ti and O are well distinguishable, imply-
ing that the Ti is oxidized. The relative peak ratio of O KLL signal to Ti LMM signal is much higher
