Metal Spark Plasma Sintering (SPS) is an advanced powder metallurgy and sintering technique used to consolidate and densify powder materials, including metals and ceramics. The process involves the application of pulsed direct current (DC) and high temperatures under a uniaxial pressure to facilitate rapid sintering and densification. Metal Spark Plasma Sintering offers advantages such as short processing times, high heating rates, and the ability to achieve high-density components with fine microstructures. Here are the key features and steps involved in Metal Spark Plasma Sintering:
Powder Preparation:
The process begins with the preparation of fine powder particles of the metal or ceramic material to be sintered. The powder may undergo various treatments to control particle size, distribution, and composition.
Die Filling:
The powder is placed in a die or mold, which defines the shape and dimensions of the final component. The die is often made of graphite or other conductive materials.
Application of Pressure:
Uniaxial pressure is applied to the powder within the die to compact it and create a green compact. This pressure helps in removing porosity and improving density.
Spark Plasma Sintering (SPS):
The die containing the green compact is placed within a spark plasma sintering machine. The machine consists of two electrodes, typically made of graphite, and a pulsed direct current (DC) power supply.
Pulses of high current pass through the powder compact, generating heat due to resistive heating. This rapidly raises the temperature of the powder.
The combination of pressure, high temperature, and pulsed current enables rapid sintering and densification. The process is completed in a relatively short time compared to conventional sintering methods.
Densification and Consolidation:
The powder particles experience localized melting and recrystallization, leading to the formation of a dense, fully consolidated material.
The high heating rates and pressure during SPS contribute to achieving