Immediately after vacuum sintering, high-pressure gas (usually inert gas such as argon or nitrogen) of 50 bar (about 5 MPa) is introduced. It can produce significant and beneficial pressure-assisted sintering effects. This is usually called gas pressure sintering or low pressure sintering. Although it is fundamentally different from HIP but has better effects than single vacuum sintering with lower cost and simpler process.

Effects of this combination of vacuum sintering + 50 bar gas pressure:

> Further promotes densification, helps to collapse the remaining interconnected pores or partially close the pores, and promotes particle rearrangement and material migration

> Accelerate the formation of closed cells and pore spheroidization, which can be more effective in improving the toughness and fatigue performance of the material than simply reducing the porosity.

> Suppression of volatile element losses (key advantage!), Especially for special alloys (such as some brasses, bronzes, high-speed steels, and stainless steels) or some alloys containing volatile elements (such as zinc Zn, cadmium Cd, manganese Mn, chromium Cr, etc.).

> Improve surface quality, Inhibiting the volatilization of elements prevents surface holes and uneven composition caused by volatilization to achieve a smoother, more uniform surface.

> Provide a certain degree of protective atmosphere, Prevent secondary oxidation or decarburization of sintered bodies at high temperature (especially for iron-based materials).