Determination of the lattice parameters a and c for the hexagonal graphite unit cell using X-ray diffraction data.

To study the microstructural evolution of graphite and its allotropes under milling, graphite powder was processed using horizontal stainless-steel ball mills. A Ball-to-Powder Volume Ratio (BPVR) of 90 was maintained. Milling durations of 8, 16, 32, and 64 hours were investigated.
This database contains the results of X-ray diffraction (XRD) analysis and includes the necessary calculations for determining the lattice parameters a and c. Measurements were performed using an Inel EQUINOX 2000 X-ray diffractometer configured with: A curved position-sensitive detector, CoKα₁ radiation (λ = 1.78901 Å), and a germanium monochromator. The acquired data were post-processed to convert results to CuKα₁ radiation (λ = 1.5406 Å) for consistency with standard references. 2θ peak positions were calibrated using a high-purity graphite standard (99.99%, Aldrich). Thanks to this analysis, it was possible to detect changes in the intensity of the main peak, shifts in the 2θ peaks, and their broadening. From these results, the variation in the lattice parameters "a" and "c" was calculated, which proved crucial for understanding the microstructural changes caused by lattice expansión. In the document titled "Determination of Lattice Parameters a and c," the calculations performed to determine the values of the unit cell parameters a and c are detailed. First, the interplanar distance was determined using Bragg's law, based on the 2θ peak positions corresponding to the (002) and (110) planes. Subsequently, using the formula for interplanar spacing in the hexagonal crystal system, the values of c and a were derived by applying the respective Miller indices (hkl) of the aforementioned planes.
Additionally, this dataset comprises raw laser diffraction particle size analysis results. For the analysis, samples were dispersed in a 0.2% sodium hexametaphosphate solution (pH 10) and subjected to 5 minutes of ultrasonic bath treatment to ensure complete particle deagglomeration. The data reveal the dominant stages of graphite exfoliation and fracture, as well as the formation of micrometric aggregates after 64 hours.