Surface Modification and Microstructure Design of Alumina Ceramics

Abstract

Microstructures and properties of alumina ceramics are sensitive to sintering additives, and commercially available readyto-press alumina powders may not contain required sintering additives for specific applications. We show a simple and practical way of microstructure design of alumina ceramics made from the commercial powders through surface modification. The method utilizes the micro-porous feature of an alumina green body pre-sintered at 1000°C, and deposits ultra-low-density sintering additive slips onto the micro-porous substrate. The surface microstructures can be refined if an ultra-low-density MgO or SiO 2 slip is deposited onto the substrate, whereas a TiO 2 slip leads to coarser and extended grain structures. TiO 2 /MgO, SiO 2 /MgO, and TiO 2 /SiO 2 combinations have also been tested, so that various surface modifications can be achieved. Fig. 2. X-ray diffraction pattern of the alumina modified with TiO 2 /MgO slip.

Facile Mixing Process To Fabricate Fly-Ash-Enhanced Alumina-Based Membrane Supports for Industrial Microfiltration Applications

“…4,5 In the process of fabricating high-performance ceramic membranes, the ceramic supports play an important role in constructing the membrane structures, thus giving the ceramic membranes enough bending strength 6 and higher permeability. However, a ceramic support 7,8 with a high bending strength usually needs to be sintered at high temperatures (usually above 1700 °C9 ), thus requiring high energy consumption and adding to the costs of the ceramics. Otherwise, the ceramics could not have enough bending strength and may not be suitable for actual industrial applications.…”

“…Currently, water scarcity is one of the most urgent problems that needs solved because of the large amount of industrial wastewater that is produced. − Ceramic membranes have been employed in wastewater treatment because of their satisfactory chemical and thermal stability and high mechanical strength. , In the process of fabricating high-performance ceramic membranes, the ceramic supports play an important role in constructing the membrane structures, thus giving the ceramic membranes enough bending strength and higher permeability. However, a ceramic support , with a high bending strength usually needs to be sintered at high temperatures (usually above 1700 °C), thus requiring high energy consumption and adding to the costs of the ceramics. Otherwise, the ceramics could not have enough bending strength and may not be suitable for actual industrial applications.…”

Indentation size effect and wear characteristics of spark plasma sintered, hard MWCNT/Al2O3nanocomposites

“…a-Al 2 O 3 (commonly known as corundum), has several advantages over other oxide ceramics, like low density (3?97 g cm 23 ), high hardness (15)(16)(17)(18), high flexural strength (210-500 MPa), low thermal expansion coefficient (5?4-8?1|10 26 /K), extreme chemical inertness, high temperature dimensional stability (up to 1700uC in ambient), high thermal shock resistance, high dielectric strength and biocompatibility, and above all, apart from its wide availability, this oxide ceramic can be found at a reasonable price. [6][7][8][9] However, extreme brittleness of Al 2 O 3 has led towards unpredictable catastrophic failures during use. Coupled to this, poor fracture toughness (K IC ) and high temperature mechanical property retentivity are some of the critical issues that restrict the suitability of monolithic a-Al 2 O 3 as advanced high performance structural ceramic.…”