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Engineering Material & Metallurgy Mcqs

Q:

Plasma is metal spraying can obtain temperatures up to ________

A) 10,000 F B) 20,000 F
C) 30,000 F D) 60,000 F
 
Answer & Explanation Answer: C) 30,000 F

Explanation: Plasma is a luminous stream of ionized gas produced by passing a gas through an electric arc. Temperatures up to 30,000 F are economically obtained. Thus, the use of plasma permits deposition of the highest melting metals.

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Q:

Usage of ___________ for metallizing helps spray the metal powder in the correct place.

A) Air, oxygen, and combustible gas B) Oxyacetylene powder gun
C) Silicon dioxide D) Hydrogen peroxide
 
Answer & Explanation Answer: B) Oxyacetylene powder gun

Explanation: One method of metalizing employs the usage of air, oxygen, and combustible gas. This method forms loose and friable oxides. Another method employs have of oxyacetylene gunpowder, which can spray the metal powder in place or over almost any contoured surface.

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46
Q:

__________ is used as a catalyst in siliconizing.

A) Hydrogen peroxide B) Chlorine gas
C) Sulfuric acid D) Magnesium sulfate
 
Answer & Explanation Answer: B) Chlorine gas

Explanation: In siliconizing, the work is heated in contact with a silicon-bearing material such as silicon carbide. Here, chlorine gas is used as a catalyst. This process is carried out at a temperature of 1700-1850 F.

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39
Q:

Siliconizing is otherwise known as _________

A) Chromizing B) Nitriding
C) Ihrigizing D) Oxy-cyaniding
 
Answer & Explanation Answer: C) Ihrigizing

Explanation: Siliconizing consists of impregnation of an iron-base material with silicon. Siliconizing is a diffusion process done to improve wear resistance. It is otherwise also known as Ihrigizing.

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Q:

Chromizing is carried out at a temperature of _________

A) 400-600 F B) 800-1200 F
C) 1650-2000 F D) 2250-2750 F
 
Answer & Explanation Answer: C) 1650-2000 F

Explanation: The chromizing process employs the principle of transfer of chromium through the gas phase at elevated temperatures. This temperature ranges between 1650 and 2000 F. This process is used on drop-forging dies, tools, hydraulic rams, pistons, and pump shafts.

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48
Q:

Which of the following is a use for flash anodic coatings?

A) Cartridge cases B) Airplane propeller
C) Paint adherence D) Hydraulic pistons
 
Answer & Explanation Answer: C) Paint adherence

Explanation: The production of the hard wear-resistant surface by anodizing has greatly extended the uses of magnesium and its alloys. Flash anodic coatings are often used as a base for paint adherence. Anodizing of zinc produces a coating which has a greater resistance to wear than chromite films.

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49
Q:

The alumilite process uses ________ as an electrolyte for anodizing.

A) Sulfuric acid B) Hydrogen peroxide
C) Nitric acid D) Ammonium sulfate
 
Answer & Explanation Answer: A) Sulfuric acid

Explanation: The anodizing process is usually applied to aluminum, magnesium, zinc, and their alloys. The alumilite process was developed by the Aluminum Company of America. This process uses sulfuric acid as an electrolyte for anodizing.

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45
Q:

What is the hardness of a rhodium plate?

A) 140-425 Vickers B) 540-640 Vickers
C) 720-880 Vickers D) 950-1050 Vickers
 
Answer & Explanation Answer: B) 540-640 Vickers

Explanation: The hardness of rhodium plate is between 540 and 640 Vickers and it has a wear resistance between that of nickel plate and chromium plate. The hardness of chromium plate is 950-1050 Vickers, whereas that of nickel plate is 140-425 Vickers.

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