Dependence of microwave dielectric properties on crystallization behaviour of CaMgSi2O6 glass-ceramics

Abstract The effects of the crystallization behaviour of CaMgSi 2 O 6 (diopside) glass-ceramics on their microwave dielectric properties were investigated as functions of the Cr 2 O 3 content and heat-treatment method used (one or two steps). The crystallization behaviours of the specimens were affected by the Cr 2 O 3 content as well as by the heat-treatment method employed, and were evaluated using X-ray diffraction and the combined Rietveld and reference intensity ratio (RIR) method. The dielectric constants ( K ) of the specimens did not change significantly with an increase in the Cr 2 O 3 content. The quality factor (Qf) of the specimens increased for Cr 2 O 3 contents of up to 0.5 wt% Cr 2 O 3 , but then decreased for higher contents. These results could be attributed to the degree of crystallization. For the same Cr 2 O 3 content, the specimens that underwent a two-step heat treatment showed lower K values and higher Qf values than those heat-treated in one-step. These results could be attributed to the smaller crystallite size and higher degree of crystallization in the specimens obtained from the two-step heat treatment compared with those of the specimens heat-treated in one-step method.