Concentration changes due to cathodic protection

By solving the appropriate diffusion equations the concentration changes are calculated in the environment of underground structures protected cathodically. It is shown that these changes are negligible under all practical circumstances

Ion and mixed conducting oxides as catalysts

This paper gives a survey of the catalytic properties of solid oxides which display oxygen ion or mixed (i.e. ionic + electronic) conductivity. Particular consideration is given to the oxidation-reduction reactions of gas phase components, but attention is also devoted to oxygen exchange between gas and oxide. An attempt has been made to relate and explain the observed phenomena such as catalytic activity and selectivity in terms of the electrical conducting properties of the oxides, which depend on their crystal and defect structures.\ud \ud In a number of cases possible applications of these materials in (electro)catalytic reactors, sensors, fuel cells, oxygen pumps, etc. are indicated

Quantitative measures of corrosion and prevention: application to corrosion in agriculture

The corrosion protection factor (c.p.f.) and the corrosion condition (c.c.) are simple instruments for the study and evaluation of the contribution and efficiency of several methods of corrosion prevention and control. The application of c.p.f. and c.c. to corrosion and prevention in agriculture in The Netherlands is considered in detail. Attention is paid to relations between c.p.f. and c.c., the corrosion costs, possible cost savings and the applied corrosion protection scheme on farms. It is shown that the c.p.f. and the c.c. are useful expedients in a preliminary analysis of corrosion costs and possible cost savings on farms in relation to the corrosion protection methods applied.\ud \ud It is concluded that significant cost savings on arable farms can be derived by improving corrosion protection. No statistically significant cost savings are possible by improving corrosion protection on the dairy farms considered in this research

The thermal decomposition of potassium and sodium-pyrosulfate

Proceeding from KHSO4, K2S2O8, NaHSO4 and Na2S2O8, potassium- and sodium-pyrosulfates were prepared and their thermal decomposition was investigated by a T.G.A. method. This was done in order to clarify contradictory values found in the literature. The presence of an intermediate with composition K2SO5 was detected

Chemical considerations on passivity

It can be shown that the value of the charge/radius ratio of metallic ions determines whether the metal on dissolution tends to become passive or not. Using this criterion it is possible to clarify the influence of pH and electrode potential on the occurrence and breakdown of passivity

Electrocatalytic phenomena in gas phase reactions in solid electrolyte electrochemical cells

The recent literature on electrocatalysis and electrocatalytic phenomena occurring in gas phase reactions on solid, oxygen conducting electrolytes is reviewed. In this field there are a number of different subjects which are treated separately. These are: the use of electrochemical methods to study catalytic phenomena, electrocatalysis proper, the transfer of oxygen at the electrodes or electrolyte, and the (electro)catalytic properties of mixed, electronic and ionic, conducting materials

The effect of yttrium ion implantation on the sulphidation of incoloy 800H

Previous work has shown the beneficial effect of yttrium implantation on the oxidation behaviour of chromium oxide forming alloys. Because of the limited applicability of Fe-Cr-Ni alloys in sulphur containing gases the effect of yttrium implantation on the sulphidation of Incoloy 800H was studied. In short time tests a significant improvement was observed upon implantation of about 1016 yttrium ions/cm2 if an oxidizing treatment was applied before exposition to the sulphiding environment. The explanation of this effect is probably similar to that proposed in the literature for the improved oxidation resistance