Scanning Electron Microscopy and X-Ray Microanalysis

428

24

BSE Al

Ni

20 μm

Fe

0.001

0.1

0.01

1.0

0.1

10

1.0

100 wt%

. Fig. 24.16 Logarithmic Three-Band Color encoding of the quantitative compositional maps for Al, Fe, and Ni derived from the Raney nickel alloy XSI

Fe

20 μm

Fe

Fe raw intensity

elemental map

Fe compositional map

0.001

0.1

0.01

1.0

0.1

10

1.0

100 wt%

. Fig. 24.17 Direct comparison of the Fe total intensity map and the Logarithmic Three-Band Encoding of the Fe quantitative compositional
map. Note the distinct changes in the contrast within the trace concentration (C < 0.01) regions of the image

major-minor-trace spatial relationships among the elemental

constituents are readily discernible.

The Logarithmic Three-Band Encoding of the Fe compo-

sitional map in. Fig. 24.16 reveals apparent Fe contrast in the

Al-rich and Fe-rich phases, and this contrast differs markedly

from the atomic-number dependence of the X-ray continuum

seen in the raw Fe intensity image, as shown in. Fig. 24.17.

The Logarithmic Three-Band Encoding shows that this appar-

ent contrast occurs near the lower limit of the trace range. Is

this trace Fe contrast meaningful or merely an uncorrected

Chapter 24 · Compositional Mapping