Fig a b and c shows respectively the

In previous investigations, other authors [40] demonstrated that the sintering of materials containing MgO, Al2O3 and SiO2 is mainly related to the ion LY335979 of Mg2+, Al3+ and Si4+. When cerium oxide is added to such system, it improves the ionic diffusion in solid phase. If a liquid occurs, a low CeO2 content decreases its viscosity and facilitates crystallization of the Mg containing phases; conversely, a higher content enables gathering of Ce4+ into the glass network, limiting ion diffusion and shifting crystallization to higher temperatures. Moreover, the behaviour of glass crystallization in MgO–Al2O3–SiO2–CeO2 system showed chlorophyll b the addition of CeO2 reduces the temperature of glass softening, delays the crystallization of μ-cordierite and shifts the μ>α conversion to higher temperatures [41] and [42]. All the materials prepared in the present study have compositions which fall in the composition ranges of system MgO–Al2O3–SiO2, being limited in their iron content. It seems therefore reasonable that the presence of CeO2 influence the sintering process by phenomena similar to those above reported.