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Effects of Pore Morphology on the Fabrication and Mechanical Properties of Porous Si3N4 Ceramics

Porous Si3N4 ceramics with different pore morphologies have been fabricated, utilizing organic whiskers and starch as the fugitive agents. The effect of the various pore types on mechanical properties, specifically flexural strength was invesigated. Permeability was also assessed.

20 Sep 2005

Application of Crystal Chemistry in the Development of Radioactive Wasteforms

The role of crystal chemistry in developing ceramic materials for high level radioactive waste immobilisation is reviewed. Synroc, a ceramic material utilising 4 titanate phases was produced that was able to incorporate nearly all elements present in high level radioactive waste.

20 Sep 2005

Diffusion Brazing of Cast Inconel 738 Superalloy

Diffusion brazing is an effective method for joining hot section components of aircraft and power generation turbines made from superalloys like IN 738. In this study, the influence of brazing temperature and time on microstructure of vacuum brazed cast IN 738 superalloy with commercial fillers “NB

20 Sep 2005

Aqueous Suspension Process of Multi-Dimensional Alumina/Nickel Nanocomposites

Multi-dimensional Al2O3/Ni nanocomposites with preserved multifunctional magnetic properties are successfully fabricated by an aqueous monomer suspension casting and coating processes. An optimal chemistry was found producing a composite with density 99.27% and bend strength 586MPa.

20 Sep 2005

Formation of Metastable Phases of the Ni-Al System by Mechanical Milling

The mechanical alloying of pre-alloyed intermetallic Al-Ni compounds was performed and bulk samples were fabricated from the mechanically alloyed powders. The alloying and its effects on phase transformations were evaluated. Properties such as hardness, porosity and density are reported.

20 Sep 2005

Preparation of Polycarbosilane Using a Catalytic Process

Polycarbosilane was synthesized from polydimethylsilane in the presence of zeolite as a catalyst. Characterization of synthesized polycarbosilane was performed with 29Si Solid State NMR, FT-IR, TPD, TGA, XRD and GPC analysis. The number average molecular weight (Mn) ranged between 300 and 2500.

20 Sep 2005

Photocatalytic Behavior of Ceramic Compounds with Similar Structures: Ba3Li2Ti8O20 and AmM2nO4n+1(A=Li, Na, K; m=2, n= 3)

Using an acidic sol-gel processes to produce compounds with similar structures to Ba3Li2Ti8O20 results in lower surface areas and porosity and hence lower catalytic activity. Catalytic bahviour was improved when basic conditions were employed. Crystal stucture was also found to be an important facto

19 Sep 2005

Internal Structure of Zirconia Nano-Powder Compact Evaluated by an Infrared Microscope

Infrared (IR) light microscopy with liquid immersion technique was found to be effective in examining the internal structure of zirconia and other nano-powder compacts. The internal structure could be observed clearly even for this high refractive index material.

19 Sep 2005

Hot Gas Filtration Using Porous Silicon Carbide Filters

Porous silicon carbide candle-type filters suitable for the condition of pressurized fluidized-bed combustion (PFBC) operations were prepared by several processes. Filtering characteristics of the porous filters with different geometry, tube-type and cogwheel-type, and various porosities were invest

19 Sep 2005

Synthesis of Bi2MexV1-xO5.5-1.5x (Me: Co, Cu) By The Citrate Gel Method

BIMEVOX Bi2MexV1-xO5.5-1.5x solid electrolytes for potential use in fuel cells have been synthesized by the citrate gel method. The gels have been prepared by mixing solutions of bismuth, vanadium and metal nitrates. Powders have higher conductivity compared to those from solid state routes.

19 Sep 2005