nano sized materials shows some extra peaks in the XRD pattern along with the peaks for bulk materials. but the higher angles peaks matches well.
Hi Arpita:
Assuming that your XRD equipment is ok, it could be:
1. If the ball mill procedure is really long and exhaustive, it can happen that your bulk material can have something coming from the balls (Depending on the material of them ZrO2, Stainless steel, WC-W6C). Normally, they contain traces of other metals.
2. The ball mill procedure induces an increment of the temperature during milling. Keep an eye in the mill program, because could be that the increase of the temperature favored the formation of an impurity or secondary phase.
3. Maybe your bulk material is not stable under air/ hygroscopic or can easily decompose. Check the Chemical Data Sheet info.
Hope this can give you some hints.
Cheers,
C.
Thanks for your response. But my sample is sintered at quite high temperature so the decomposition during milling is quite unlikely.
Most of the energy (96%: Bond)in a ball mill is converted into heat (and noise and light) and not in comminuting the material. Ball milling to 'nano' dimensions typically takes many hours. Are you milling dry or wet? As explained in the earlier reply by Carlos, contamination of your sample by ball material is a given. What were your balls? Zirconia? Stainless? WC?
Looking at the XRD pattern you supplied there certainly appears to be a phase change occurring. Ball milling is sometimes used to achieve reaction between pre-cursors, although you've said that you used high temperature sintering so this should negate this as the pre-cursors appear to have already reacted (nice, high symmetry pattern in your original XRD pattern). I would look at a phase diagram for the compound you are trying to make; it is possible that there is a lower temperature phase transition occurring from your original high temperature phase to the other apparent phase in the XRD pattern.
I had dry milled the sample for about 16 hours with WC balls. I would like to know if there is any possibility of phase transition for mechanically induced strain during ball milling? What may be the new possible phase as the bulk sample was cubic with Fm -3m space group?
The bulk specimen XRD pattern looks like it's high symmetry cubic but some of the peak sizes and positions are a little funny for a fluorite like Fm-3m (e.g. no peak at around 35 2-theta, and a big peak around 45 2-theta). The secondary phase is a bit of a mystery to me, at a glance it doesn't look like orthorhombic, hexagonal or monoclinic symmetry to me but to properly analyse it you should find some reference patterns from the main symmetries and work your way back from there.
Suggestions for maximizing leverage of the combined intellect of the RG community:-)
https://www.researchgate.net/post/What_is_the_best_method_used_to_align_the_diffractometer_plane_axis_with_respect_to_the_incident_beam_direction?_tpcectx=profile_questions
i have found that there may be a tetragonal distortion from cubic phase of bulk sample in case of the nano sample. what may be the suitable ways of proving it?
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