Hot pressing

The loose powder or the pre-compacted part is in most of the cases filled to a graphite mould that allows induction or resistance heating up to temperatures of typically 2,400 °C (4,350 °F).

But the main disadvantage is the dependence of the process on good inductive coupling and thermal conductivity of the mold.

[3] The compelling reason for shortening the cycle time then was to avoid grain growth and also save energy.

Additionally, this leads to significant increase in the sintering activity of fine metal powder aggregates which makes short cycle times of a few minutes possible.

The previous two methods are both closely dependent on an intrinsic property of the mold material, i.e., its thermal conductivity.

Latest research suggests that there is no basic difference between sintering with pulsed or unpulsed current (SPS or FAST).

[citation needed] Recently, the manufacture of such critical items as sputtering targets and high-performance ceramic components, such as boron carbide, titanium diboride, and sialon, have been achieved.

The near net-shape precision achieved is very high and often eliminates mechanical reworking of materials that are often difficult to process.

In the friction material industry, direct hot pressing plays an increasing role in production of sintered brake pads and clutches.

Sintered clutch discs are predominantly used for heavy-duty trucks, vessels, tractors and other agricultural machines.

Recent development work includes metal-diamond-composite heat sinks, for example in LED and laser applications.

Sintering metal-diamond compounds with direct hot presses goes back to the 1950s since when it is commonly practised in the diamond tool industry.