Investigation of the influence of initial powder size on the optical properties of Dy-alpha-SiAlON ceramics fabricated by gas pressure sintering

Translucent Dy3+ doped alpha-SiAlON ceramics were successfully fabricated by the gas pressure sintering (GPS) method. The efficacy of this sintering technique also the affects initial particle size on densification, final microstructure and optical properties of GPS-ed Dy-alpha-SiAlON ceramics, all of which are discussed. Two types of starting powder mixtures were prepared using different milling procedures. Their primary surface area was characterized by BET analysis and morphology was characterized by scanning electron microscope (SEM). The optical translucence of the sintered Dy-alpha-SiAlON ceramics was inspected in the 1000-7000 cm(-1) wave number region using FTIR. The microstructure and phase characterization of the sintered samples were also conducted using SEM and XRD techniques, respectively. Results show that using smaller particle sized starting raw materials reduces the required sintering temperature to obtain fully densified ceramics. In addition, it reduced the average grain size of the sintered products and homogenized the distribution of the glassy phase around the alpha-grains thereby improving the optical translucence of GPS-ed Dy-alpha-SiAlON ceramics.