CeraMat

It is known that solids with composition Na3Zr2Si2PO12 heated at 1200°C crystallize in the nasicon structure. This material shows a high ionic conductivity that represents an interesting improvement in the field of solid electrolytes. Our experimental results allow to establish for the first time that nasicon structures are stable along the compositional join Na3Zr2-x/4Si2-xP1+xO12 with x extending from 0 to 1.667. These structures are characterized by a Zr underoccupation of octahedral sites and a constant number of Na+ ions.

An investigation of the thermolysis of 3% yttria doped zirconia samples has been undertaken using the method of Controlled transformation Rate Thermal Analysis (CRTA) under a residual pressure of 4.5 x 10 4 mbar. Investigation of the water washed samples reveals a simple water loss. Thermolysis of the ethanol washed samples however, reveal a series of mechanisms without ethanol production. Several ethene related species are evolved during the course of the reaction indicating the catalytic nature of zirconia.

The possible chemical interactions which occur between sodium (as sulphite), iron and cerium (as oxides) coming from pollutants or additives, and the materials which make up three commercial filters, in the working temperature of a Diesel soot filter, were considered. The commercial filters were respectively a cordierite monolith filter, a wound-fiber filter made by continuous Al2O3-B2O3-SiO 2 fibers, and a sintered Chrome-Nickel stainless steel filter plate.