1997

The unreinforced 6061 alloy and a 6061/SiC composite, at the beginning in the T6 temper, were submitted to thermal cycling (up to 2000 cycles) in the temperature ranges 25-180°C and 25-220°C. The microstructure of these materials was studied by scanning electron microscopy and mercury intrusion porosimetry. Mechanical and thermomechanical properties were also investigated. Tensile strength, hardness, Charpy impact resistance, fracture toughness, density, specimen dimensions and thermal expansion were compared before and after thermal cycling.

In Part I the chemical and microstructural nature of Cusingle bondKsingle bondV catalysts for diesel soot combustion was assessed. In this second communication the reaction mechanism of these catalysts is studied by testing their activity through either differential scanning calorimetry (DSC) or temperature-programmed oxidation (TPO), performed on catalyst-carbon mixtures.

Several formulations of a Cusingle bondKsingle bondV catalyst supported on α-Al2O3 with different Cu:K:V atomic ratios and with different loadings of the active components on the support were prepared by impregnation with aqueous solutions of KCl, CuCl2 · 2H2O and NH4VO3, drying and calcination. The composition of these catalysts, suitable for greatly accelerating the combustion of carbonaceous materials, was investigated by X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR) and scanning electron microscopy (SEM).