Question 1

Technician A says the dwell time for phosphoric acid on bare metal is approximately 10 minute. Technician A says seam sealers can be applied over bare metal surfaces. Who is correct?

Accepted Answer

The dwell time for phosphoric acid on bare metal can vary depending on the product and application, but 10 minutes is a general guideline, not a strict rule. Seam sealers typically require a primer or specific surface preparation before application on bare metal, contradicting the claim that they can be directly applied over bare metal surfaces.

Question 2

Technician A says acid rain is a known cause of oxidation on automobiles. Technician B says an insulated steel bolt or one with a special coating can be used to hold two aluminum parts together. Who is correct?

Accepted Answer

A

Question 3

____________________ adhesion occurs through chemical cross-linking when chemically matched paint products are applied over the top of each other. An example is applying a clear coat over the color coat made by the same manufacturer.

Accepted Answer

Chemical

Question 4

A ____________________ primer is a two-component primer which uses a phosphoric acid as reducer or vehicle which will also ensure proper etching of the surface over which it is applied.

Accepted Answer

The answer of A ____________________ primer is a two-component primer...

Question 5

Technician A says te zinc phosphate coating will re-generate if a galvanized steel surface is scratched. Technician A says weld-through coating vaporizes and burns away in the weld zone as the weld nugget sufficiently protects the metal and it is no longer needed. Who is correct?

Accepted Answer

Technician A is correct in stating that the zinc phosphate coating will re-generate if a galvanized steel surface is scratched. This is due to the corrosion-resistant properties of zinc, which react with oxygen and moisture in the atmosphere to form a protective layer of zinc oxide.

Technician B is incorrect in stating that weld-through coating vaporizes and burns away in the weld zone as the weld nugget sufficiently protects the metal and it is no longer needed. In fact, weld-through coatings are designed to remain in place during welding and provide additional protection for the metal against corrosion.

Question 6

An E-coating is a sprayed-on for corrosion protection that the manufacturer applies before shipping.

Accepted Answer

E-coating, or electrocoating, is a method of applying paint or coating to metal parts that involves dipping the parts into a paint bath and applying an electrical charge to deposit the paint onto the parts evenly. It is not typically sprayed on.

Question 7

Galvanic corrosion is a form of corrosion that occurs when two of more different types of metal come into contact with each other, causing the more reactive metal to break down.

Accepted Answer

This is the definition of galvanic corrosion.

Question 8

The process whereby one metal is coated with a thin layer or coating of another metal is called ____________________ . This is commonly done by hot-dipping or electroplating the steel to form a thin layer of zinc over the steel.

Accepted Answer

The answer of The process whereby one metal is coated...

Question 9

Technician A says galvanic corrosion is a desirable form of corrosion. Technician B says the zinc coating on galvanized steel is a form of sacrificial corrosion. Who is correct?

Accepted Answer

Technician B is correct because the zinc coating on galvanized steel acts as a sacrificial anode to protect the underlying steel from corrosion, which is a deliberate use of sacrificial corrosion. Galvanic corrosion is not desirable as it involves the deterioration of metals when they are in electrical contact in the presence of an electrolyte.

Question 10

A sacrificial corrosion is a form of corrosion in which one metal such as zinc oxidizes, sacrificing itself to form a protective coating over another metal, thus slowing down the deterioration of the first metal.

Accepted Answer

This is an accurate explanation of sacrificial corrosion.

Question 11

Technician A says steel rust is a form of preservation. Technician B says passivation is a self protective coating generated by aluminum. Who is correct?

Accepted Answer

Passivation is indeed a process where a material becomes less affected by environmental factors such as air or water by forming a protective coating, and aluminum is known for naturally forming an oxide layer that protects it from further corrosion. Steel rust, on the other hand, is not a form of preservation but rather a form of corrosion that deteriorates the metal.

Question 12

Technician A says weld through coating may be either a zinc or copper base. Technician B says that seam sealers are applied to joints of vehicles to protect against corrosion. Who is correct?

Accepted Answer

The answer of Technician A says weld through coating may...

Question 13

A corrosion hot spot is an area that forms after metal has been heated above 1000 degrees F.

Accepted Answer

A corrosion hot spot refers to an area that is more susceptible to corrosion than the surrounding material, not necessarily related to being heated above 1000 degrees F. Factors like material defects, environmental conditions, or chemical exposure can create corrosion hot spots.

Question 14

Mechanical adhesion is achieved by sanding and abrading the surface, allowing the finish to 'bite' into or anchor itself to the walls of the sand scratches.

Accepted Answer

Mechanical adhesion relies on creating roughness or texture on the surface for the finish to grip onto, which is achieved through sanding and abrading.

Question 15

Technician A says corrosion hot spots can occur as result of welding during the repairs. Technician B says a self healing corrosion protective compound is commonly used on inside door panels. Who is correct?

Accepted Answer

Technician A is correct as welding can cause corrosion hot spots due to the intense heat generated during the repair process. Technician B is also correct as self-healing corrosion protective compounds are commonly used on the inner door panels to protect them from corrosion. Therefore, both technicians are correct.

Question 16

Technician A says that wax-based anti-corrosion compound is a self-healing compound. Technician B says epoxy primers offer optimum protection against corrosion for bare steel. Who is correct?

Accepted Answer

Wax-based anti-corrosion compounds are indeed self-healing, meaning they can flow back into scratches or damages on the surface, providing continuous protection. Epoxy primers are known for their excellent adhesion and corrosion resistance properties, making them an optimal choice for protecting bare steel from corrosion.

Question 17

Technician A says the magnesium coating on the galvanized steel corrodes to protect the steel surface. Technician A says that aluminum does not corrode, and therefore will last much longer than steel. Who is correct?

Accepted Answer

Technician A is incorrect because it is the zinc in galvanized steel, not magnesium, that corrodes to protect the steel surface. Technician B is incorrect because aluminum does corrode, but it forms a protective layer of aluminum oxide that prevents further corrosion, which is different from not corroding at all.

Question 18

Technician A says that magnesium does not corrode and is lighter and stronger than steel. Technician B says a marine environment commonly results in an accelerated oxidation process. Who is correct?

Accepted Answer

Technician B is correct because magnesium does corrode, especially quickly in marine environments due to the accelerated oxidation process. Technician A is incorrect in stating magnesium does not corrode; while it is lighter and can be stronger than steel, it is susceptible to corrosion.

Question 19

____________________ is a form of degradation of steel, aluminum, or nearly any other metal or form of matter, wherein the material reacts with oxygen together with an electrolyte, usually water, causing the material to break down and eventually dissipate.

Accepted Answer

The answer of ____________________ is a form of degradation of...

Question 20

A ____________________ primer is material that has a tendency to absorb moisture or water, causing it to corrode.

Accepted Answer

The answer of A ____________________ primer is material that has...

Quiz 19: Corrosion Protection