Potentiodynamic polarization studies were carried out on virgin specimens of amorphous alloys Ti₄₈Cu₅₂, Ti₅₀Cu₅₀ and Ti₆₀Ni₄₀ in 0.5 M HNO₃, 0.5 M H₂SO₄ and 0.5 M NaOH aqueous media at room temperature. The value of the corrosion current density (𝐼_corr) was maximum for Ti₄₈Cu₅₂ alloy in all the three aqueous media as compared to the remaining two alloys. The value of 𝐼_corr for the alloy Ti₄₈Cu₅₂ was maximum (𝐼_corr = 2.6 × 10^-5 A/cm²) in 0.5 M H₂SO₄ and minimum (𝐼_corr = 3.5 × 10^-6 A/cm²) in 0.5 M NaOH aqueous solutions. In contrast, the alloy Ti₆₀Ni₄₀ exhibited the least corrosion current density in 0.5 M HNO₃ (𝐼_corr = 4.0 × 10^-7 A/cm²) and in 0.5 M NaOH (𝐼_corr = 5.5 × 10^-7 A/cm²) aqueous media as compared to those for Ti–Cu alloys, while its value in 0.5 M H₂SO₄ was comparable to that for Ti₅₀Cu₅₀. It is suggested that the alloy Ti₆₀Ni₄₀ is more corrosion resistant than the alloys Ti₄₈Cu₅₂ and Ti₅₀Cu₅₀ in all the three aqueous media.

A precursor for zirconia – 8 mole% yttria (YSZ–ZrO₂–8 m% Y₂O₃) powder was prepared by coprecipitation and the calcination temperature was fixed as 900°C from TG–DTA and XRD studies. The calcined powder could be dry ground only to a mean particle size (𝐷₅₀) of 6 𝜇m containing substantial amount of coarse agglomerates in the size range 10–100 𝜇m. The dispersion conditions for its wet grinding were evaluated through zeta-potential and viscosity studies. The zeta-potential variation with pH of the aqueous suspensions of the powder exhibited maximum numerical values at 3 and 11 pH, exhibiting the ideal pHs for dispersion stability through electrostatic columbic repulsion mechanism. Slurries of dry ground powders with solid concentration in the range 15–30 vol.% exhibited pseudo-plastic flow characteristics, indicating presence of flocculates. With progress of grinding, the increase in viscosity of the slurries became less significant with decreasing solid concentration. Even though the particle size of the ground slurries decreased with decreasing solid content, there was little change in it for slurries with solid content < 20 vol.%. Grinding conditions for formation of sinter-active powders of YSZ with sub-micron size (𝐷₅₀\ ∼ 0.7 𝜇m free of agglomerates of size > 5 𝜇m) were established. Compacts from this powder could be sintered at 1400°C to translucent bodies with 99% theoretical density.