Microwave assisted sintering of Nanostructured Infrared-Transparent Nd0.1Y1.9O3 ceramics Synthesized by a Modified Combustion Technique

Abstract

Synthesis of nano particles of Nd0.1Y1.9O3 ceramics (∼15nm) by a single step auto-igniting combustion technique, followed by microwave sintering to optimum density, and their remarkable infrared transmission characteristics are presented in this paper. The XRD pattern of the as prepared sample clearly indicates that the Nd3+ ions are effectively replacing Y3+ ions in the yttria cubic structure and it matches very well with the JCPDS file no-89-5591. The size of the crystallites was calculated using Scherrer formula and they found to be in the size range of 10-19 nm and the average size of the crystallites was 15 nm. The HRTEM analysis confirms the nano nature and the well-defined lattice structure of the sample. The UV-Visible and FTIR spectroscopy were effectively used to characterise the powder and to obtain the transmittance properties of the sintered samples. Microwave heating was successfully employed to sinter the sample pellets. A soaking duration of 20 minutes at 1500°C yielded well sintered (98.8% ) translucent pellet with reduced average grain size of 500nm and it showed a transmittance of 77% in the UV-Visible region and 78% in the mid infrared region. Microwave assisted sintering of the combustion synthesized powder is therefore a promising fabrication technique, especially for infrared transparent ceramics, which considerably reduces the sintering temperature, soaking duration, the grain size and enhances the transmittance properties. These results clearly indicate that by prudently tuning the concentration of the additives, the IR transmittance properties can be improved and they can be used very effectively for the fabrication of infrared transparent windows and domes.