**7.7 Erosion corrosion**

It is the increase of attack of a metal because of relative movement between a corrosive medium and the metal surface. This type of erosion corrosion is usually associated with systems where high velocities of corrosive fluids or gases are encountered.

#### **Figure 5.**

*Schematic representation of pitting corrosion.*

#### **Figure 6.**

*Schematic representation of intergranular corrosion.*

**9**

**Figure 9.**

*Schematic representation of stress corrosion.*

*Corrosion Inhibitors*

**7.8 Stress corrosion**

**Figure 8.**

• Chemical composition

*Schematic representation of erosion corrosion.*

**7.9 Corrosion fatigue**

environment.

• Preferential orientation of grains

• Composition and distribution of precipitates

*DOI: http://dx.doi.org/10.5772/intechopen.80542*

This corrosion can be observed in piping system such as bends, elbows, pumps and condensers, etc. A Schematic representation of erosion corrosion is shown in **Figure 8**. Factors affecting erosion corrosion are nature of surface film, corrosion environment and presence of air bubbles with its size, chemical composition, suspended solids,

The cracking of metal or alloy by the combined action of a tensile stress and a corrodent **(Figure 9)** is known as stress corrosion cracking. The susceptibility to

• Dislocation structure and environmental factors and structure of metal.

It is defined as, "the reduction of the fatigue strength due to the presence of corrosive environment". Corrosion fatigue occurs due to the combined action of tensile and compressive stress alternatively. Fatigue occurs at lower stress in corrosive

corrosion resistance and metallurgical properties of metals and alloys.

stress corrosion cracking is due to certain metallurgical factors such as,

**Figure 7.** *Schematic representation of selective leaching corrosion.*

*Corrosion Inhibitors*

**7.6 Selective leaching**

**7.7 Erosion corrosion**

Selective leaching is the removal of an element from an alloy by corrosion. Selective removal of zinc from brass is a prime example of this form of attack. A similar attack has been observed with other alloys in which iron, aluminum, cobalt and chromium are removed. This type corrosion is undesirable as it yields a porous

It is the increase of attack of a metal because of relative movement between a corrosive medium and the metal surface. This type of erosion corrosion is usually associated with systems where high velocities of corrosive fluids or gases are encountered.

metal with poor mechanical properties (**Figure 7**)**.**

**8**

**Figure 7.**

**Figure 5.**

**Figure 6.**

*Schematic representation of pitting corrosion.*

*Schematic representation of intergranular corrosion.*

*Schematic representation of selective leaching corrosion.*

**Figure 8.** *Schematic representation of erosion corrosion.*

This corrosion can be observed in piping system such as bends, elbows, pumps and condensers, etc. A Schematic representation of erosion corrosion is shown in **Figure 8**. Factors affecting erosion corrosion are nature of surface film, corrosion environment and presence of air bubbles with its size, chemical composition, suspended solids, corrosion resistance and metallurgical properties of metals and alloys.
