In this research, fused silica-zirconia composites including of 5 % by weight of zirconia stabilized yettria prepared by Spark Plasma SINTERING (SPS) method. The powders were mixed by Spex (8000D, High energy ball mill) for 30 min in ethanol media. After mixing process, the ethanol removed by heating of the batches at 70 °C. The prepared samples were sintered at 1100, 1200 and 1300 °C and final pressure of 30 MPa. FESEM images demonstrated distribution of reinforcements at the fused silica matrix, also the results showed that sintered samples at 1200 °C have better properties than other samples. Relative density, flexural strength, hardness and toughness of these samples were 99.99 %, 13.4 GPa, 131 MPa and 4.46 MPa.m1/2 respectively. Also results showed that with increasing of SINTERING temperature to 1300 °C, due to crystallization in fused silica and as a result the formation of cracks in matrix, flexural strength decreased but the hardness and toughness increased slightly.

In this research, the production possibility of TiC-Al2O3 nanocomposite, as a useful ceramic from commercially pure TiO2, aluminum powder and carbon black has been investigated. Routile (TiO2) with carbon black and aluminum were placed in a high energy ball mill and sampled during different milling times. Then, the activated powders were synthesized at different temperatures in an atmosphere control tube furnace. Our results show that using this method has decreased the synthesizing temperature to 1000-1250oC by increasing the milling time. Also the width of X-ray patterns peaks, had made it apparent that, the size of produced TiC crystals was in order of nanometer. Furthermore it was detected that the lattice parameter deviated slightly from the standard size.

In this work, lithium meta titanate (Li2 TiO3 ) nanocrystallites were synthesized by the hydrothermal method and subsequent heat treatment. The shrinkage of the powder compact was measured under constant heating rate in order to study the SINTERING behavior of the synthesized powders. The densication curves of the synthesized powders were also constructed via the dilatometry analysis and evaluated at several heating rates. Two separate methods, including analytical procedure and master curve SINTERING were employed to determine the activation energy of the initial SINTERING stage. Results showed that activation energy values obtained from these two distinct methods (229± 14 and 230 kJ/mol, respectively) were consistent with each other. It was revealed that the dominant mechanism of densication on initial SINTERING of Li2 TiO3 nanocrystallites is surface diffusion

In this study, Y3Al5O12-MgAl2O4 (YAG-Spinel) composites, with different molar ratios (1: 1 and 1: 3), were in-situ fabricated using Reactive Spark Plasma SINTERING (RSPS) technique. To this end, Al2O3, MgO, and Y2O3 powders were used as the starting materials. In-situ formation of YAG-Spinel composites was investigated based on the reaction 3. 5 Al2O3 + MgO + 1. 5 Y2O3 → Y3Al5O12 + MgAl2O4. Both synthesis and densification processes were accomplished using a single-cycle RSPS with one-step heating. The RSPS process was performed at a SINTERING temperature of 1300 ° C for 30 min hold time with a maximum uniaxial pressure of 90 MPa under vacuum conditions. The synthesized phases and microstructures were investigated by X-ray diffraction and field emission scanning electron microscopy. The unwanted phases such as YAP (YAlO3) in a composite microstructure were removed using LiF additive. LiF was used as a SINTERING aid in the process of SINTERING. The in-situ synthesized YAG-Spinel composites exhibited no internal infrared transmittance over the infrared wavelength ranges of 2. 5-25 μ m.

Hydroxyapatite (HAp, Ca10(PO4)6(OH)2), a calcium phosphate bio ceramic which is chemically similar to natural bone mineral, is widely used as a scaffolding material in bone tissue engineering. In this study, Hydroxyapatite (HAp) ceramics were sintered using microwave in one- and two-step heat treatment. The SINTERING temperatures in the first heat treatment step were in the range of 965-1000 °C without isothermal holding, and the power levels of the microwave were set at 600, 750, and 900 W. The temperatures in the second heat treatment step were 600, 735, and 860 °C. Of note, HAp-to-Tricalcium phosphate (TCP) phase transformation was not detected at 1000 °C; instead, the preferred growth of (211) planes corresponding to the circular morphology was observed. As observed in the XRD images, crystallite degradation occurred in two-step sintered samples. In addition, the SEM micrographs indicated that the open porosity in the two-step heat treated samples was more than that of samples which were heat treated in one step. In case the SINTERING temperature was set at 1000 °C, the maximum density values of 92 % and 95 % were obtained for one- and two-step sintered samples, respectively.