Which of the following is correct about powder metallurgy?

Explanation:

Powder Metallurgy

• Powder metallurgy is a manufacturing process in which various metal powders are compressed and then heated to form a solid piece. This process is used to create materials and components with unique properties that are difficult to achieve through traditional metalworking techniques. Powder metallurgy is particularly advantageous for producing parts with complex shapes, high precision, and controlled porosity. 

Working Principle:

The powder metallurgy process generally consists of the following steps:

1. Powder Production: Metal powders are produced using various methods such as atomization, reduction, electrolysis, or mechanical alloying. The choice of method depends on the desired properties of the final product.
2. Blending: The metal powders are blended with lubricants, binders, and other additives to ensure uniformity and enhance the properties of the final product.
3. Compacting: The blended powder is compacted in a die under high pressure to form a "green compact." This compact is not yet fully dense and retains the shape of the die.
4. Sintering: The green compact is heated in a controlled atmosphere furnace to a temperature below its melting point. During this process, the metal particles bond together, reducing porosity and increasing strength. Sintering involves heating the compacted metal powder to a temperature that is high, but still below the melting point of the material. This allows the particles to bond together and form a solid piece, while maintaining their individual properties and shape.
5. Post-Sintering Operations: Depending on the application, additional processes such as machining, heat treatment, or surface finishing may be performed to achieve the desired properties and dimensions.

Applications:

Powder metallurgy is used in a wide range of industries, including automotive, aerospace, medical, and electronics. Common applications include:

• Gears, bearings, and other mechanical components with complex shapes.
• High-performance materials such as tungsten carbide and titanium alloys.
• Porous materials for filters, sensors, and catalytic converters.
• Magnetic materials for motors and electronic devices.