View Single Post
Old 5th April 2009, 01:00 PM   #292
Sunstealer
Illuminator
 
Sunstealer's Avatar
 
Join Date: Oct 2007
Posts: 3,128
I am looking at the possibility that the material that Jones has is Kaolin or China Clay and Iron Oxide (not sure of the exact type, but I'm coming to the conclusion that it is Fe2O3 commonly known as haematite or red iron oxide). Both of these substances are widely used in the paint industry.

http://www.mineralco.net/kaolin/index.php
http://www.mineralco.net/red-iron-oxide/index.php

If you look at the compositions here http://www.dhirajlal.com/minerals.html you can clearly see that there is a good match for the spectra that Jones comes up with. Notably Fig 7 sample c). You can clearly see that this is slightly different from the other 3 samples because it contains Na, S, K and Ca in addition to the commonality of C, Fe, O, Si, Al.

Looking at the SEM photo Fig 4 - you can clearly see that there are two distinct layers with different morphologies. This rules out thermite - no ifs or buts, it's not thermite. I'll guarantee that there won't be pure Aluminium in the sample either. The bottom or "gray layer" is consistently shown to be iron oxide of some type and is clearly a complete layer and is not in particle form. There is no way that this is going to be able to react with any Aluminium because it doesn't have sufficient enough surface area, it's not a particulate. This indicates that it is not thermite.

Kaolin with added lime (CaO) is also found in concrete and mortar.

The Carbon is the one that is foxing me. Originally I thought it could be from the conductive carbon tape that is used to hold the samples to the stage. It's more likely that this is in the form of Calcium Carbonate which is used in both cement and paint (as an extender) manufacture.

Here is a high quality SEM photo of Kaolin http://www.sem-edx-lab.uni-tuebingen...d5b352a015.jpg taken from this site.

Compare and contrast the plate-like structures with Figs 8, a-c). Note also how they say

Quote:
Again it was observed that the thin sheet-like particles are rich in Al and Si
Page 15 (bottom under fig 9). - Kaolin, Al2Si2O5(OH)4

Compare there Fig 11a) EDS of these plate-like structures with Kaolin

http://www.scielo.org.ar/scielo.php?...pt=sci_arttext (Note: The Au is gold and you can ignore it, because it is the metallisation of the sample - you won't get any Fe or C (and I'm not sure whether the C is from the tape and they aren't too sure about it either), because it's a pure sample, however the Al, Si and O peaks and the characteristic of the spectra are identical. I'm certain that what they are looking at with regard to the plate-like structures is Kaolin Al2Si2O5(OH)4. Thermite does not contain Kaolin.

I'll have to take another look at the bright particles, because these seem to be an iron oxide of some sort. The SEM images need to be labelled with the exact parts where they are taking the EDS from and composition. Grrr it's a bit sloppy.

I'll leave it at that for the moment, but from what I've looked at this definitely isn't thermite.

Last edited by Sunstealer; 5th April 2009 at 01:18 PM.
Sunstealer is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Back to Top