Análise comparativa entre diferentes ensaios porosimétricos em alumina macroporosa

ABSTRACT Macroporous ceramics of Al2O3 are being studied due their diverse applications (biomaterials, anode for solid oxide fuel cells, etc.). The pore distribution, size and interconnection are important parameters that can determine physical and mechanical characteristics of these materials. The aim of this study was analyze and compare different methods of porosimetry. For this, we used the mercury intrusion porosimetry (PIM), Archimedes method (MA), micrographic analysis (AM) and nuclear magnetic resonance with CPMG radiofrequency pulses (1H-RMN - CPMG). Samples of macroporous Al2O3 were obtained by the gelcasting method modified by incorporation of polyethylene spheres at different amounts. The results of these porosimetry methods were treated mathematically, and then the Pearson correlation between the pore size distributions were analyzed. The main advantage of the MA was the simplicity to obtain the apparent porosity, although this method did not provide the pore size distribution. The pore size distribution obtained by 1H-RMN - CPMG was similar to those obtained by PIM. The similarity of these results was evidenced by the high value of Pearson correlation (r > 0.962) between these methods. The analysis of pore homogeneity and morphology were better obtained by AM method. Although, when AM were compared with PIM we observed differences in the pore size distribution. These were evidenced by the low value of Pearson correlation (r < 0.048). Thus, unconventional porosimetry methods (1H-RMN - CPMG and AM) could be used as an alternative to conventional (PIM and MA) to characterize macroporous materials.