External and internal factors influencing the rate and distribution of corrosion are discussed. Among the external factors considered are: pH of the solution, influence of elements acting as inhibitors or as stimulants of corrosion, the concentration of neutral salts, the temperature of solution and the rate of solution movement. Corrosion damage caused by stray electric currents is described in detail and measures eliminating or minimizing their effect are suggested.
Internal factors considered include the inherent chemical properties of elements (that is, their position in periodic table). However, a distinction is made between chemical and corrosion stability, because of the possibile formation of protective films. Furthermore, the influence of internal stresses as well as of alternating stresses in metals in corrosive media (corrosion fatigue) is described. Surface conditions influencing corrosion are mentioned. Stability of monophasic and of heterophasic alloys and the influence of grain size on corrosion are discussed. Finally, experimental data on stability limits of solid solutions and related phenomena such as dezincification are given and some attempts at the explanation of stability limits of solid solutions are mentioned. 3.8.4