Synthesis and characterisation of Mg_xCu_1–xNb₂O₆ (x = 0, 0·2, 0·4, 0·6, 0·8, 1) for LTCC application

Abstract

A series of Mg_xCu_1–xNb₂O₆ (x = 0, 0·2, 0·4, 0·6, 0·8, 1) columbites has been prepared using sol–gel technique. The samples were sintered at 900°C for 6 h to study the suitability for low temperature co-fired ceramics (LTCC) application. Structural characterisation of the prepared samples has been carried out using the X-ray diffraction method. Lattice parameters and densities have been calculated. Microscopic characterisation is studied using field emission scanning electron microscopy. Microwave dielectric properties like dielectric constant and Qf factor for all the compositions have been measured. Dielectric constant is found to fall between 5 and 10 with a Qf factor of 3000 to 17 000 GHz. Thermal properties like thermal conductivity and thermal coefficient of expansion (TCE) have been measured. While thermal conductivity is found to be of the order of 1–2 W m⁻¹ K⁻¹, TCE is of the order of 5–10×10⁻⁶ °C⁻¹. The thermal properties and the application are not reported earlier for these compounds. These properties are found to match the required properties of LTCC.

Keywords:

• LTCC
• Sol–gel
• Dielectric constant
• Qf factor
• Thermal conductivity
• Thermal coefficient of expansion