EFFECT OF VAPOR ATMOSPHERE ON THE FORMATION REACTION OF MSIO(3) (M=MG, CA, SR AND BA)

Effect of vapor atmosphere on the formation reaction of MSiO(3) (M = Mg, Ca, Sr and Ba) from various precursor powders was investigated by powder X-ray diffraction. Precursors of MgSiO3 and CaSiO3 were prepared by the coprecipitation method by adding NH4OH to ethanol solution dissolving a respective nitrate and tetraethyl orthosilicate (TEOS). Those of SrSiO3 and BaSiO3 were prepared from respective hydroxide powder and TEOS. Vapor atmosphere showed the most effective influence in the formation of CaSiO3, whereas it showed the least influence in that of MgSiO3 among the four kinds of MSiO(3) formation. The difference in effect was mainly attributed to the degree of chemical homogeneity of the precursor powder, the effect being smaller the higher the chemical homogeneity. The samples fired under a vapor atmosphere showed larger specific surface area than those under a dry atmosphere.