Influence of green state processes on the sintering behaviour and the subsequent optical properties of spark plasma sintered alumina

Investigation of the Characteristics of Barium Strontium Titanate (Bst) Dielectric Resonator Ceramic Loaded on Array Antennas

“…The microstructures that have uniform grain size and high relative density are expected to have a higher dielectric constant, which has been tested for utilization in microwave applications. This also was reported in several publications [19].…”

Processing of Alumina and Corresponding Composites

“…An in-depth study (Aman et al, 2011) of SPS of high-purity (99.99%) a-alumina fine (z170 nm) powders has demonstrated that for pressures around 80 MPa, relatively low heating rates (z300 C min À1 ) are much favorable to achieve near-full density with fine-grained size at low sintering temperatures (z1100 C). The preforming of the green compacts as well as the SPS parameters have to be carefully selected as a function of the processed material to avoid differential sintering effects and attain full-density bodies (Aman, Garnier, & Djurado, 2009;Aman, Garnier, & Djurado, 2010;Jayaseelan, Ueno, Ohji, & Kanzaki, 2004;Mishra et al, 1998).…”

“…Decreasing the grain size and the residual porosity of high-purity alumina down to 0.27 mm and 0.03%, respectively, by controlling the SPS parameters allows reaching in-line transmission of 47% (Kim et al, 2007). Aman and coworkers have studied the influence of the green state and the SPS parameters in translucency of alumina (Aman et al, 2009) and reached values of in-line transmission z40% for high-density (>99.97% of theoretical) materials with grains of about 1 mm. For the same specimen thickness (0.8-1 mm), in-line transmissions in the range of 50-79% depending on grain size (0.34-0.50 mm) and surface preparation have been reported by Krell et al for slip-cast and hot-pressed or gel-cast, pressureless, sintered and hot-pressed high-purity alumina of 150 nm starting size Krell, Hutzler, & Klimke, 2009).…”

Sintering of α-alumina for highly transparent ceramic applications

“…Some authors have chosen the spark plasma sintering (SPS) technique to densify their samples and control the grain growth. [7][8][9] Here, we used the hot isostatic pressing (HIP) technique. First of all, we will present a brief state of the art of that research topic before outlining the transparency calculus in a polycrystalline alumina.…”