Nitriding is a process of heating steel in atmosphere of :

Options

A. ammonia
B. oxygen
C. carbon dioxide
D. air

Answer

To solve the question regarding the nitriding process, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Nitriding**:
- Nitriding is a heat treatment process that involves the introduction of nitrogen into the surface of steel to improve its hardness and wear resistance.

2. **Identifying the Atmosphere Used**:
- The process requires a specific atmosphere to facilitate the absorption of nitrogen into the steel.

3. **Analyzing the Options**:
- The options given are:
- A) Ammonia
- B) Oxygen
- C) Carbon Dioxide
- D) Air
- Among these, we need to identify which one is suitable for nitriding.

4. **Selecting the Correct Option**:
- The correct atmosphere for nitriding is ammonia (NH3).
- Ammonia provides a source of nitrogen that diffuses into the steel surface when heated.

5. **Conclusion**:
- Therefore, the answer to the question "Nitriding is a process of heating steel in atmosphere of" is **A) Ammonia**.

### Final Answer:
Nitriding is a process of heating steel in an atmosphere of **Ammonia**.

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