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Lower Sintering Temperature (lower + sintering_temperature)
Selected AbstractsEffect of Applied Stress on IR transmission of Spark Plasma-Sintered AluminaJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2010Dibyendu Chakravarty The effect of applied stress on IR transmittance of nanocrystalline alumina prepared by spark plasma sintering was evaluated. Transparent alumina with maximum transmittance >80% was obtained over the entire mid-IR wavelength range of 3,5 ,m by applying a high stress of 275 MPa at 1150°C using specially designed high-strength compound dies. The transmittance observed was similar to previous reports at identical wavelengths, but at a lower sintering temperature. The transparent samples have an average grain size of 0.3 ,m and a hardness of 23 GPa. At lower stresses and sintering temperatures, transmittance reduced drastically due to remnant pores in the matrix as observed from the microstructural analysis. The effect of porosity was found to be critical in developing transparency as even a marginal decrease in porosity led to substantial increase in transmittance. [source] Oxidation Kinetics and Mechanisms of Hot-Pressed TiB2,MoSi2 CompositesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2008Golla Brahma Raju The densification of titanium diboride (TiB2) at lower sintering temperature requires the use of sinter-aid. However, from the high temperature application point of view, it is important to assess whether the presence of sinter-aid degrades the material properties, including the oxidation resistance. In the present work, the isothermal oxidation behavior of TiB2 - x wt% MoSi2 (x=0, 2.5, and 10) composites was carried out using thermogravimetric analyzer in order to study the effect of MoSi2 content on the oxidation kinetics of TiB2 at 1200°C for a duration of 12 h. The oxidized surface of monolithic TiB2 composed of highly textured rod-like rutile (TiO2) crystals. In contrast, the oxide scales on TiB2,MoSi2 materials consist of a thin layer of SiO2 along with TiO2. Interestingly, the analysis of the continuous measurements of the weight gain reveals parabolic rate law of oxidation for all the investigated ceramics. However, the oxidation kinetics is slower for the TiB2 -10 wt% MoSi2, probably due to the presence of SiO2 in the oxide scale. [source] Synthesis, Physical, and Mechanical Properties of Bulk Zr3Al3C5 CeramicJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2007Lingfeng He An in situ reactive hot-pressing process using zirconium (zirconium hydride), aluminum, and graphite as staring materials and Si and Y2O3 as additives was used to synthesize bulk Zr3Al3C5 ceramics. This method demonstrates the advantages of easy synthesis, lower sintering temperature, high purity and density, and improved mechanical properties of synthesized Zr3Al3C5. Its electrical and thermal properties were measured. Compared with ZrC, Zr3Al3C5 has a relatively low hardness (Vickers hardness of 12.5 GPa), comparable stiffness (Young's modulus of 374 GPa), but superior strength (flexural strength of 488 GPa) and toughness (fracture toughness of 4.68 MPa·m1/2). In addition, the stiffness decreases slowly with increasing temperature and at 1600°C remains 78% of that at ambient temperature, indicating that Zr3Al3C5 is a potential high-temperature structural ceramic. [source] Development of Nanocrystalline Wear-Resistant Y-TZP CeramicsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2004Bikramjit Basu The present contribution reports some interesting and new results obtained while developing yttria-stabilized tetragonal zirconia (Y-TZP) using spark plasma sintering (SPS). The experimental results clearly showed that ZrO2 -nanoceramics with high hardness(,14.5 GPa) can be processed at a lower sintering temperature of 1200°C in a short time (5 min). Another important result is that the newly developed Y-TZP nanoceramics, compared with the conventional sintered TZP, exhibit better fretting wear resistance against bearing steel. The intergranular fracture and the grain pullout were observed as the major wear mechanisms of the zirconia nanoceramics. [source] Study on Synthesis and Electrochemical Properties of Nanophase Li-Mn-spinelCHINESE JOURNAL OF CHEMISTRY, Issue 3 2003Feng Chuan-Qi Abstract Li-Mn-spinel was synthesized using the rheological phase reaction method. First, the precursor was prepared by rheological phase reaction. Then it was decomposed to form Li-Mn-spinel, which was characterized by X-ray diffraction analysis and IR spectra. The particle size of Li-Mn-spinel was determined by the method of the transmission electron microscopy. The synthesized materials are of nanometer size with 30,100 nm in the average diameter. The electrochemical properties of the Li-Mn-spinel were also studied. It proved that this method not only provided a simple practicable and effective route for the synthesis of Li-Mn-spinel, but also had many advantages such as lower sintering temperature, shorter sintering time, fine particles and particularly excellent electrochemical performances. [source] Preparation of Titanium Foams by Slip Casting of Particle Stabilized Emulsions,ADVANCED ENGINEERING MATERIALS, Issue 8 2009Bram Neirinck Bulk titanium foams were prepared by emulsion templating during slip casting. The emulsion template was stabilized using partially hydrophobized titanium particles while the continuous phase consisted of a titanium hydride powder suspension. Sintering was performed in inert atmosphere. The use of titanium hydride resulted in lower sintering temperatures and denser, stronger struts. Both homogeneous foams with high compressive strength and structures with a gradient in pore size were obtained. [source] | ||||||||||