Synthesis and characterization of TiO2 ceramic substrates obtained by processes of the compaction and slip casting

Resumo

The aim of this work is to obtain ceramic substrates based on titanium oxide (TiO₂) by powder compaction and slip casting. The ideal support must show interconnected porosity in the range of 30 to 35%. The function of ceramic supports is to provide mechanical resistance when covered by a thin layer of a colloidal solution (sol-gel) of TiO₂, forming a ceramic membrane. Membranes are defined as a barrier that separates the two phases and that restricts, totally or partially, the transport of one or several species present in the phase [1]. Ceramic membranes are refractory and have high chemical stability, resistance to high temperatures and radiation [2]. The techniques used in this work for obtaining ceramics substrates were by slip casting in plaster molds and by the process of compacting dry powders in spray-dryer, pressure of 1.5 kgfcm^-². The ceramic substrates were sintered at temperatures of 1100 and 1150ºC/1h. The Tables 1 show the geometric and hydrostatic porosity of the substrates milling for 15 and 60 min and sintered at the temperatures of 1150ºC and 1100ºC, respectively. The Table 2 shows the hydraulic permeability of both substrates sintered to 1150ºC. Permeability is the measure of the greater or lesser ease that the support offers a passage of a given solvent, in this case, water. The supports obtained by slip casting presented porosity below the ideal (30-35%), while the slip casting ground for 60 min and sintered at 1100ºC showed porosities between 33-35%, ideal for application as a ceramic substrate.