Rietveld refinement of a sulfide corrosion powder

Sulfide corrosion is a common occurrence in petroleum (gas) pipelines and sanitary sewers. Design of new corrosion resistant materials is based on the knowledge of chemical compounds present in the sulfide corrosion powder.

X-ray diffraction data were collected on a sulfide corrosion sample using Rigaku's Ultima IV multipurpose diffraction system. Phases were identified as shown in Figure 1.

Based on a model structure, calculated from these phases, Rietveld analysis was performed. Figure 2 shows the experimental data (orange), the resultant calculated data (green) and the residual (top blue).

A screen shot from the Jade Whole Pattern Fitting ( WPF ) software module for Rietveld analysis shows the residual parameters of the refinement including R/E (Figure 3).

R/E is a fitting parameter that quantifies the result of the fit, relative to what is theoretically possible. Quantitative results from the analysis are presented in Figure 4.