“Magnesia-stabilized β-wollastonite” inhibiting transformation from β to α in the region of high temperature: Transition enthalpy by calorimetry

Wollastonite has been widely studied as a ceramic raw material of calcium silicate (CaSiO 3 ).Recently, Mg-doped wollastonite has attracted increasing attention due to its enhanced mechanical, insulative and bioactive properties.However, synthesizing single phase Mg-doped wollastonite is not easy because wollastonite undergoes crystal phase transition from -CaSiO 3 to -CaSiO 3 at around 1200 .Therefore, it is important to establish practical synthesis method of Mg-doped wollastonite for future application studies.In this study, -Ca 0.92 Mg 0.08 SiO 3 was successfully synthesized at 1300 by two-step sintering of Mg-containing xonotlite, which inhibits the transformation from to at high temperatures.The first step facilitates complete Mg diffusion into -CaSiO 3 , while the second step promotes Mg diffusion from diopside (CaMgSi 2 O 6 ) to -CaSiO 3 without occurring - phase transformation.Owing to the stabilization of the low-temperature -phase at high temperatures through magnesia addition, the material was named "magnesia-stabilized -wollastonite (MSW)" in reference to yttria-stabilized zirconia (YSZ).