Answer
As discussed in Section 17.7 of this book,
1. Galvanic Corrosion- Avoid an unfavorable anode-to-cathode surface area ratio. Use an anode area as large as possible. Electrically insulate dissimilar metals from each other. Electrically connect a third, anodic metal to the other two.
2. Crevice Corrosion- Use welding instead of riveted or bolted joints. Removing accumulated deposits frequently. Using non-absorbing gaskets when possible.
3. Pitting- Use welding instead of riveted or bolted joints. Removing accumulated deposits frequently. Using non-absorbing gaskets when possible.
4. Intergranular corrosion- for a stainless steel, the following can be done to prevent intergranular corrosion:
a. subjecting the sensitized material to a high-temperature heat treatment in which all the chromium carbide particles are redissolved
b. lowering the carbon content below 0.03 wt% C so that carbide formation is minimal
c. alloying the stainless steel with another metal such as niobium or titanium
5. Erosion corrosion- changing the design to eliminate fluid turbulence and impingement effects. Use of other materials that can inherently resist erosion. Removal of particulates and bubbles from the solution lessens its ability to erode.
6. Stress corrosion- Lowering the magnitude of the stress. Reducing the external load or increasing the cross-sectional area perpendicular to the applied stress. Use of an appropriate heat treatment to anneal out any residual thermal stresses.
7. Hydrogen embrittlement- Reducing the tensile strength of the alloy via a heat treatment. Removing the source of hydrogen, “baking” the alloy at an elevated temperature to drive out any dissolved hydrogen, and substituting a more embrittlement-resistant alloy.
Work Step by Step
As discussed in Section 17.7 of this book,
1. Galvanic Corrosion- Avoid an unfavorable anode-to-cathode surface area ratio. Use an anode area as large as possible. Electrically insulate dissimilar metals from each other. Electrically connect a third, anodic metal to the other two.
2. Crevice Corrosion- Use welding instead of riveted or bolted joints. Removing accumulated deposits frequently. Using non-absorbing gaskets when possible.
3. Pitting- Use welding instead of riveted or bolted joints. Removing accumulated deposits frequently. Using non-absorbing gaskets when possible.
4. Intergranular corrosion- for a stainless steel, the following can be done to prevent intergranular corrosion:
a. subjecting the sensitized material to a high-temperature heat treatment in which all the chromium carbide particles are redissolved
b. lowering the carbon content below 0.03 wt% C so that carbide formation is minimal
c. alloying the stainless steel with another metal such as niobium or titanium
5. Erosion corrosion- changing the design to eliminate fluid turbulence and impingement effects. Use of other materials that can inherently resist erosion. Removal of particulates and bubbles from the solution lessens its ability to erode.
6. Stress corrosion- Lowering the magnitude of the stress. Reducing the external load or increasing the cross-sectional area perpendicular to the applied stress. Use of an appropriate heat treatment to anneal out any residual thermal stresses.
7. Hydrogen embrittlement- Reducing the tensile strength of the alloy via a heat treatment. Removing the source of hydrogen, “baking” the alloy at an elevated temperature to drive out any dissolved hydrogen, and substituting a more embrittlement-resistant alloy.
