This display is from a Thermo-Noran EDS system. The number to the right of the colour bar in each case is the number of counts from the pixel(s) showing the maximum intensity in the image. So in this instance the Al shows a higher intensity than Cu and Ni, while O is barely above the background level.

Hi Li,

The letter K indicates that it is due to radiation emanating from K shell. 

I am not sure about the other answer.

Hello,

I agree,the K stands for X-rays emitted when electron transitions to the K-shell occur.

The numbers next to the color scales should represent counts, i.e., how many X-rays of a given energy were detected during the aquisiton at a given point on the sample (=pixel on the map image).

This display is from a Thermo-Noran EDS system. The number to the right of the colour bar in each case is the number of counts from the pixel(s) showing the maximum intensity in the image. So in this instance the Al shows a higher intensity than Cu and Ni, while O is barely above the background level.

In addition to what Ian Slipper have said:

Even if Al map shows higher intensity than that of Cu and Ni, we cannot assume that concentration of Al is higher. 

Map of O should be discarded, it has no information about distribution of O, just shows distribution of background radiation (which is lower for lighter elements, such is Al in your case). 

Sill an additional comment: K displays that this spectral part of the respective element shown. Usually you can select different characteristic parts if it is beneficial (e.g. in case of peak overlapping) and available. 

Dear Prof. Gert Nolze

What about if one element is not shown in EDX due to overlap. Is it possible to get any information from EDS mapping image of this element.

Thanks

Regards,