Dear SAMI, 

i RECENTLY used Particle analyser working on diffration and Mie theory for the measurement of particle size and characterization of cement paste and solution

though this answer is not of ur concern but just wanted to share with u 

for ur answer have a look into the following links 

http://www.akademiai.com/doi/abs/10.1007/s10973-005-7353-9

http://www.sciencedirect.com/science/article/pii/S0008884609002579

https://www.onepetro.org/conference-paper/SPE-37225-MS

http://www.sciencedirect.com/science/article/pii/S0950061808000548

Hi!

Can you plz upload your diffractogram?

For XRD/XRF -  sample preparation (1) grind your same to 50-100' micron, use a standard sieve size. Then make pallet (12-20mm dia) press at 5-10 kg pressure. That uniform pallet can be used for both XRD and XRF. Don't put water, organic solvent to dissolve or making powder.

Hi SAMI

The degassing temperature for gas sorption analysis (BET) depends upon the used solvents during the synthesis and thermal stability of materials to be analyzed. So prior to degassing check the thermal stability by TGA analysis.

Generally, the solvent molecules and atmospheric gaseous molecules are trapped in the pores of porous materials. The temperature range of 100 - 120  for 6 - 10 hours time duration, is sufficient for removing the low boiling solvents and trapped gaseous molecule or air. As you have used Iso-Propnol and acetone so this temperature  range will work fine for you.

During the degassing give slow heating rate (5 deg C/min max.). Sometime rapid heating destroy the porous structure.

I hope, it would be helpful.

If you need any further help, please feel free to ask.

best

raeesh

@B. Mallick  : here you go.

the sample is a fragment of hydrated CAC+OPC blended cement cured till 56 days and treated with acetone and isopropnol. it was powdered in a bowl which was washed with alcohol prior to grinding. The lab technician was of the opinion that my sample wasnt dehydrated in an oven; thats why its carrying that much noise. i do admit that I didnt properly secure the sample from moisture. is that the primary reason for the noise?

Diffraction parameters are quite OK but the scanning is very fast (nearly 5 deg/min) . Just change the receiving slit to 0.3, div. slit (0.5 ok), set to a slow scan (1deg/min), or 0.01 deg/sec, or 2 sec/step (where step= 0.04), you will get the accepted diffraction pattern. your counts are very less, so the fluctuation is normal.

B.Mallick:

Thanks! will definitely follow those instructions next time...:)

Sample preparation slightly differ for XRF and XRD.

1. Both pressed pellet and fused glass beads are suitable for hydrated cement paste or anhydrous cement samples for XRF.

2. To prepare cement samples for XRD, disc are often preferred as they overcome error due to preferential orientation.

However in both cases hydration reactions (for hydrated cement paste) should be ceased by solvent exchange or freeze drying to get reproducible data.

In BET also both disc (for eg 1mm diameter) and powder (600-1200 micrometer) can be used. But hydration need to be stopped before the measurement.