Powder metallurgy sintering is a specialized heat treatment technique that enhances the strength and characteristics of compacts or loose powders. It plays a crucial role in the powder metallurgy process. Through sintering, the powder particles undergo various physical and chemical phenomena, such as mutual flow, diffusion, melting, and recrystallization. These processes result in the densification of the powder body and the elimination of existing pores. Here are some commonly employed sintering methods:
▅Solid-state sintering: This method involves subjecting the powder body to temperatures below the melting point of its individual components, typically around 0.7 to 0.8 times the absolute melting point (Tm) measured in Kelvin.
▅Liquid-state sintering: When a powder compact consists of multiple components, sintering can occur above the melting point of a specific constituent, leading to the formation of a small amount of liquid phase within the compact during the sintering process.
▅Pressure sintering: In this approach, pressure is applied to the powder body during sintering to facilitate densification. Pressure sintering is sometimes referred to as hot pressing, which combines powder forming and sintering to directly obtain finished products.
▅Activation sintering: Certain physical or chemical techniques are employed during sintering to significantly reduce the required temperature and time, resulting in improved performance of the sintered body.
▅EDM sintering: During the forming and pressing stages, direct current and pulsed electricity are applied to the powder body, generating arcs between the powder particles for sintering. Pressure is gradually applied during sintering, combining the forming and sintering processes.
▅Infiltration sintering: This method involves contacting the porous blank with a liquid metal or alloy capable of wetting its solid surface at high temperatures. Capillary forces facilitate the filling of pores within the blank with the liquid metal. Infiltration sintering is suitable for manufacturing various alloy materials or products such as tungsten silver, tungsten copper, and iron copper, aiming to enhance their strength and other properties.
