Thermal expansion behavior of boron-doped cordierite glass-ceramics

The linear thermal expansion coefficients of cordierite glass-ceramics that have been doped with a fixed amount of P2O5 and 1, 2, and 3 wt % of B2O3 show negative expansion in the temperature range of 100 degrees-300 degrees C. The expansion of the undoped cordierite sample is positive. A relative decrease in the degree of negative expansion is observed as the B2O3 concentration increases. These negative expansion coefficients are similar to those of cordierite glass-ceramics that have been doped,vith the potassium cation.