Microstructure and mechanical properties of an alumina–glass low temperature co-fired ceramic

The microstructure and mechanical properties of an alumina–glass low temperature co-fired ceramic (LTCC) have been investigated. The microstructure was studied by using optical microscope, scanning electron microscope, energy spectrum analysis and X-ray diffraction. The Young's modulus, hardness, flexure strength and fracture toughness were measured by three-point bending, indentation and nanoindentation tests. The LTCC can be regarded as a particle-reinforced composite with macroscopically isotropic properties: particles mainly composed of synthetic corundum and matrix mainly of corundum and silica. The particles with irregular shape and an average radius of 0.71 μm are homogeneously dispersed in the matrix. The properties of the individual particle and matrix were successfully measured and further used to obtain the effective properties of the composite by micromechanics methods. The existence of rigid particles improves not only the modulus, hardness and strength but also the fracture toughness of LTCC materials.