why Backscatted electron used to show the voids

[fusitexa]

hi guys,

recently when i was reading a book, there was a photo that was a back-scatted electron imagine used to shown the voids of the failed HP45. i wonder why don't use the secondary electron imagine? attached is the picture. appreciated if any help. thanks in advance.

 

[EdStainless]

I think that it was a coincidence in this case.
BSE is nice for showing surface topology. It give a bit more clarity to minor surface variations.
My hunch is that they were using the method and got a good image of the voids.
These voids should show in SEE also.

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Plymouth Tube

 

[TVP]

I think that they used BSE because of the contrast enhancement it provides for the different phases (austenite and carbides) that are highlighted in the higher magnification (b) image. Ed is correct, voids would show up using SE as well.

 

[fusitexa]

Ed, thanks.
TVP, you make it clear.