Sometimes Intergranular corrosion is also called intercrystalline corrosion or interdendritic corrosion. In the presence of tensile stress, cracking may occur along grain boundaries.This type of corrosion is frequently called interranular stress corrosion cracking (IGSCC) or intergranular corrosion cracking.

Crevice Corrosion refers to the localized attack on a metal surface at, or immediately adjacent to, the gap or crevice between two joining surfaces. The gap or crevice can be formed between two metals or a metal and non-metallic material. Outside the gap or without the gap, both metals are resistant to corrosion. Crevice corrosion is not unique to stainless steels. It can occur in other alloys including those of aluminium, titanium and copper.

Rust is the common term for corroded steel or iron. It is very common compound, iron oxide. Iron oxide, the chemical Fe2O3, is common because iron combines very readily with oxygen. It is so readily that pure iron is only rarely found in nature. The reddish oxide produced is caused by oxygen and moisture.

Pitting is used to describe the formation of small pits on the surface of a metal or alloy. Pitting is suspected to occur in much the same way crevice corrosion does, but on a flat surface.  A small imperfection in the metal is thought to begin the process, then a "snowball" effect takes place. Pitting can go on undetected for extended periods of time, until a failure occurs. Stainless steel to a chloride containing stream such as seawater, Pitting would overrun the stainless steel in a matter of weeks due to it's very poor resistance to chlorides, which are notorious for their ability to initiate pitting corrosion.

A cathodic protection system is a corrosion cell in which the structure to be protected is the cathode. Sacrificial or galvanic systems are corrosion cells of the differential metal type. The earliest experiments on cathodic protection were performed with zinc anodes that were electrically connected to copper plates immersed in seawater. From galvanic series, an arrangement would produce a cathode (copper) and an anode (zinc). In the large galvanic cell so formed, the zinc cylinder corroded away in a manner to protect the copper substrate. This method of cathodic protection can be used with other combination of metals providing the necessary current to the metal to be protected.

Galvanic corrosion refers to corrosion damage induced when two dissimilar materials are coupled in a corrosive electrolyte.

 (ICCP)
Cathodic protection can be applied if the metal to be protected is coupled to the negative pole of a direct current source (schematic), while the positive pole is coupled to an auxiliary anode. Since the driving voltage is provided by the DC source there is no need for the anode to be more active than the structure to be protected.

Electronic rust prevention for cars

The basic principle of cathodic protection  is very simple. A metal dissolution is reduced through the application of a cathodic current. Cathodic protection is often applied to coated structures, with the coating providing the primary form of corrosion protection. The CP current requirements tend to be excessive for uncoated systems.

Pitting corrosion can produce pits with their mouth open (uncovered) or covered with a semi-permeable membrane of corrosion products.

Explanation of the Rusting of Iron

When iron rusts a spontaneous redox reaction occurs, between the oxygen and iron. If water is added the rusting occurs more rapidly.

High Temperature Failure Analysis

Creep occurs under load at high temperature.  Boilers, gas turbine engines, and ovens are some of the systems that have components that experience creep.  An understanding of high temperature materials behavior is beneficial in evaluating failures in these types of systems.

Castings

Several factors effect the quality of metal castings.