The effect of oxygen excited by low energy electrons on the oxidation of corrosion resistant alloys was investigated using a Thermo Cahn Microbalance with an rf low energy plasma source. For examining the effect of Cr on the oxidation, six alloys with different Cr contents like stainless steel were used as specimen materials. The excitation condition of oxygen by low energy electrons was optimized with the plasma diagnosis and theoretical calculation. The test condition was controlled in 20Pa oxygen at the temperature range of 473K to 873K. The oxidation behavior was evaluated based on both in-situ weight change and the depth profile of oxide film by XPS. The oxidation rate evaluated by the oxide depth was decreased with increasing Cr contents in alloys and markedly accelerated in the excited oxygen compared with the gaseous oxygen. The mass loss behavior in the excited oxygen was observed in alloys with high Cr contents and metallic Cr due to the evaporation of CrO3. The oxidation behavior in the excited oxygen was analyzed with the surface reaction model that is the evaporation pressure of CrO3 at the oxide outer layer based on a Kellogg type thermodynamic diagram of CrOx(solid)-CrOy(gas)-Po2.
Pd-Sn alloys were electrodeposited from alkaline baths containing Pd (NH3)Cl2, K2SnO3 and thioglycolic acid. The compositions of the deposits were almost constant at around Pd-50mass%Sn in the current density range from 0.2A/dm2 to 2A/dm2. The major components of the deposits were PdSn and other intermetallic compounds.