J. Jayaraj

Corrosion studies on Fe-based amorphous alloys in simulated PEM fuel cell environment

Abstract In this paper, we introduce a novel idea of using metallic amorphous material as a bipolar plate for polymer electrolyte membrane fuel cell (PEMFC). The major requirement of the metallic bipolar plate material is their high corrosion resistance. Owing to its chemical homogeneity, and absence of defects (like grain boundaries, dislocations, etc.), amorphous materials exhibit a combination of attractive properties for bipolar plates such as high corrosion resistance and high strength (~ about 2 GPa). The corrosion properties of Fe48Cr15Mo14Y2C15B6 and of a newly developed Fe50Cr18Mo8Al2Y2C14B6 bulk metallic amorphous alloys have been investigated under conditions that simulate the fuel cell environment and are compared with those of a stainless steel. Hydrogen gas and pressurized air were bubbled into a 1 M H2SO4+2 ppm F- solution at 75 °C solution, throughout the experiment to simulate the respective anodic and cathodic PEMFC environment. In comparison to the stainless steel, the Fe50Cr18Mo8Al2Y2C14B6 amorphous alloy displays significantly higher corrosion resistance.

Globulization mechanism of the primary Al of Al−15Cu alloy during slurry preparation for rheoforming

Semisolid slurries of Al-15Cu alloy were produced for rheoforming by a low temperature pouring technique. To investigate the morphological change of the slurry in terms of the particle mean diameter and the roundness factor, samples were extracted during the continuous cooling and the isothermal holding stage of the slurry by a simple technique of interrupt quenching. Results demonstrated that the fine-grained equiaxed dendritic structure, which formed during low temperature pouring, is changed to a globular structure when held at a semisolid temperature for sufficiently long holding time. With regard to the globulization mechanism of the primary α-phase, local melting is considered to take place at the neck of equiaxed dendrites, leading to the separation of small new particles during continuous cooling. These newly formed particles eventually grow during isothermal holding in the semisolid temperature by obeying theD3=Kt kinetic law, which suggests coarsening by Ostwald ripening.

Synthesis and characterization of nanometer-sized Ti-based amorphous powders

two-phase amorphous alloys.The initial microstructure of these rapidly quenched alloys is composed of Ti-based,amorphous, spherical, nanometer-sized particles embedded in a Y-based amorphousmatrix, with particle size dependent on the alloy composition. The Ti-based powderswere extracted from the two-phase amorphous alloys through selective dissolution ofthe Y-rich matrix in a 0.1 M HNO

Potential of Cr2AlC Ternary Carbide as Material for Bipolar Plate in PEMFC

In this paper, we present results of an investigation on the physical, mechanical, chemical properties and processing ability of the Cr2AlC ternary carbide bulk material synthesized by hot pressing technique. The combination of excellent properties indicated that Cr2AlC ternary carbide alloy could be potential candidate materials as bipolar plates in polymer membrane fuel cell (PEMFC).