Practice Exam Questions And Correct

Ohio Coating & Corrosion Inspector Practice Exam Questions And Correct Answers (Verified Answers) Plus Rationales 2025|2026 Q&A | Instant Download Pdf

• What is the primary cause of corrosion in steel structures?
• Lack of sunlight
• Dry air exposure
• Electrochemical reactions between metal, oxygen, and moisture
• Low temperatures

Rationale: Corrosion is an electrochemical process involving metal,

oxygen, and moisture forming rust.

• What is the main function of a protective coating?
• To improve the look of the structure
• To act as a barrier between the metal and the environment 1 / 3

• To reduce metal hardness
• To increase conductivity

Rationale: Coatings are applied to prevent corrosive agents from

reaching the metal surface.

3. Rust is chemically known as:

• Iron chloride
• Iron sulfate
• Iron oxide
• Iron carbonate

Rationale: Rust is the oxidation of iron, producing iron oxide.

• The most common method of surface preparation before applying

coatings is:

• Washing with detergents
• Abrasive blasting
• Chiseling
• Heating the surface

Rationale: Abrasive blasting removes rust, scale, and old coatings to

create proper profile.

5. The term “Dew Point” refers to:

• Temperature of coating curing
• Air temperature
• Temperature where moisture condenses on the surface
• Metal temperature only 2 / 3

Rationale: Dew point is the temperature at which air becomes

saturated and water forms on surfaces.

• Which instrument is used to measure ambient humidity?
• Micrometer
• Hygrometer
• Thickness gauge
• Pit gauge

Rationale: Hygrometers measure relative humidity in the

atmosphere.

7. A coating failure caused by trapped solvents is referred to as:

• Flash rust
• Corrosion creep
• Solvent entrapment (blistering)
• Undercutting

Rationale: Solvents that do not escape before curing create blisters

and defects.

8. Holiday detection is used to find:

• Color mismatch
• Pinholes or voids in a coating film
• Surface roughness
• Dry film thickness variation

Rationale: Holiday detectors locate breaks or bare spots in coatings.

• / 3