Influence of sintering conditions and laser radiation on the surface microstructure, chemical composition, and electrical conductivity of CuO/Ag ceramics

The influence of the third harmonic radiation of a YAG: Nd$^{3+}$ laser on the microstructure, chemical composition, and electrical conductivity of CuO and CuO/Ag ceramic samples subjected to heat treatment under different conditions has been investigated. It has been found that the surface morphology is almost identical for all the samples sintered at the same temperatures. According to the X-ray microanalysis, the ratio of the copper and oxygen concentrations (Cu/O) increases with an increase in the sintering temperature and upon quenching cooling of the samples. It has been shown that laser irradiation changes the micro-structure of the samples, increases the concentration ratio Cu/O, and leads to the inclusion of silver atoms into the lattice of copper oxides. It has been revealed that the temperature dependence of electrical resistance of all the studied samples in the temperature range of 80–300 K has a semiconducting character, and the activation energy of electrical resistance varies in the range from 0.19 to 0.48 eV. The activation energy of electrical resistance decreases with an increase in the sintering temperature of the samples and increases upon their quenching, whereas the laser treatment leads to a weakening of the dependence of the activation energy on the sintering temperature. The deposition of a silver layer before the laser treatment has no noticeable influence on the activation energy. The obtained data can be used to purposefully change the physical properties of compounds formed in the Cu–O–Ag system.