PCS Material Selection 5

Question 1

Thermal spray aluminum (TSA) is often preferred over thermal spray zinc in which environment?

Accepted Answer

Marine and elevated-temperature service such as CUI

Answer

TSA performs well in seawater and elevated temperatures where zinc may consume rapidly or reverse polarity.

Question 2

Why is coal tar epoxy use declining in many U.S. projects despite good immersion performance?

Accepted Answer

Health and environmental concerns over polycyclic aromatic hydrocarbons

Answer

Coal tar contains PAH carcinogens, prompting regulatory restrictions and owner preference for alternatives.

Question 3

When choosing a topcoat for an existing aged alkyd system, which is the main risk of using a strong-solvent two-component epoxy?

Accepted Answer

Lifting or wrinkling of the old alkyd from aggressive solvents

Answer

Strong solvents can soften and lift oxidatively cured alkyds, so compatibility testing is essential.

Question 4

Which factor is most critical when selecting coatings for low-temperature application in winter?

Accepted Answer

The minimum cure temperature specified by the manufacturer

Answer

Each coating has a minimum substrate and air temperature below which it will not cure properly, so low-temp versions may be required.

Question 5

In a galvanic couple, why should a small anodic area coupled to a large cathodic area be avoided in material selection?

Accepted Answer

It concentrates corrosion on the small anode, accelerating attack

Answer

An unfavorable area ratio focuses galvanic current on the small anode, causing rapid localized corrosion.

PCS - Protective Coatings Specialist Certification Practice Test