Effect of Zr substitution on the microwave dielectric properties of (Ca0.8Sr0.2)TiO3 ceramics

• New microwave dielectric properties of (Ca0.8Sr0.2)(ZrxTi1−x)O3 ceramics were investigated.
• Improvement of dielectric properties was achieved by (Ca0.8Sr0.2)(ZrxTi1−x)O3 ceramics.
• The ɛr of ceramics increases from 26 to 178, and Q × f increased from 5700 to 11,500 GHz with x from 0.1 to 1.
• The τf value decreased from +915 ppm/°C for x = 0.1 to −7 ppm/°C for x = 1.

Solid-state reaction process has been used to fabricate (Ca0.8Sr0.2)(ZrxTi1−x)O3 ceramics, and several characteristics of the (Ca0.8Sr0.2)(ZrxTi1−x)O3 ceramics have been investigated. The substitution ratio effects on the different phase change and the quality factors of (Ca0.8Sr0.2)(ZrxTi1−x)O3 ceramics were improved because of the solid solution of Zr4+ substitution in the B-site. An excess of Zr4+ resulted in the formation of high amount of secondary phase of CaZrO3 and SrZrO3 with higher quantity of substitution, affecting the microwave dielectric properties of (Ca0.8Sr0.2)(ZrxTi1−x)O3 ceramics. The temperature coefficient of resonant frequency (τf) of (Ca0.8Sr0.2)(ZrxTi1−x)O3 ceramics also improved with increasing Zr content, and the variation in τf was attributed to the formation of secondary phase of CaZrO3 and SrZrO3.

The dielectric constant of sintered ceramics increases from 26 to 178, and the Q × f value increased from 5700 to 11,500 GHz with x from 0.1 to 1. The τf value decreased from +915 ppm/°C for x = 0.1 to −7 ppm/°C for x = 1, and the secondary phase may be responsible for the variation.Figure optionsDownload as PowerPoint slide