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Physical & Chemical properties

Nanomaterial crystallite and grain size

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Administrative data

Endpoint:
nanomaterial crystallite and grain size
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The study was regarded as scientifically acceptable. Contributions to the widths of Xray diffraction peaks from crystal strain and instrument effects are assumed to be zero. Using XRD the average particle size can be estimated. Specific factors can influence the peak width, such as microstrain, lattice defects and temperature factors. Due to the limited documentation it was not possible to estimate the influence of these factors to the result. Thus, the study was regarded as reliable with restrictions.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report date:
2012

Materials and methods

Test guideline
Qualifier:
no guideline followed
GLP compliance:
no
Type of method:
x-ray diffraction (XRD)
Details on methods and data evaluation:
D S-XRD was calculated using Scherrer’s formula. It should be noted that a variety of factors can contribute to the width of a diffraction peak; besides crystallite size, the most important of these usually are inhomogeneous strain and instrumental effects. When Scherrer’s formula is applied, it is assumed that all of these other contributions to the peak width are zero.

Test material

Constituent 1
Test material form:
solid: nanoform
Specific details on test material used for the study:
Name of test material: Z-cote ®
Code: NM110
Supplier: BASF SE
Surface coating: none
- Substance type: Inorganic
- Physical state: solid powder, nano-form

-Name of test material: Z-cote HP
Code: NM111
Supplier: BASF SE
Surface coating: triethoxycaprylylsilane (2%)
- Substance type: Inorganic
- Physical state: solid powder, nano-form

-Name of test material: NanosunTM
Code: NM112
Supplier: Micronisers
Surface coating: none
- Substance type: Inorganic
- Physical state: solid powder, nano-form

-Name of test material: Zinc Oxide
Code: NM113
Supplier: Sigma-Aldrich
Surface coating: none
- Substance type: Inorganic
- Physical state: solid powder, nano-form

Data gathering

Instruments:
Bruker ASX-D8 X-Ray Diffractometer (XRD) using Cu K(alpha) radiation

Results and discussion

Applicant's summary and conclusion

Executive summary:

CSIRO, 2012 investigated the crystallite size of the nanomaterials. Two methods were used to estimate average crystallite size based on XRD results. Crystallite size of the test samples were calculated using Scherrer’s formula (D S-XRD) and through Rietveld refinement of the diffraction data (D R-XRD). The crystallite size of the test samples determined in two independent experiments calculated using Scherrer’s formula were comparable for all nanomaterial samples. The crystallite sizes determined by XRD were in the range of 24 nm (NM‑112) to 42 nm. Both NM‑110 and NM‑113 have the same crystallite size of 42 nm. The average crystallite size determined by Rietveld refinement yielded larger crystallite sizes. This result could be explained by the fact that the Scherrer’s formula ignores the contributions of width broadening due to strain and instrument effects. If these contributions are non-zero, the crystallite sizes could be larger than those predicted by the Scherrer formula, as revealed by Rietveld refinement of the diffraction data (D‑R XRD). These data were regarded as most reliable.

 

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