[mikejharrison]

Over the years I’ve seen a couple of fascinating applications with powdered additive manufacturing. Living metal - powdered metal parts with bacteria ‘in the gaps’. Activated with heat their byproduct was lubricant. Great for bearing faces in mechanical equipment doing long distances in space.

The other was calcium powdered 3D printed parts that had a chemical forced through their porous mass, changing its chemical composition.

[hwillis]

The specialist applications of powder metallurgy are awesome, not to mention the fact that lots of refractory metals can only be used with sintered powder (eg tungsten). It should also be pointed out that powder metallurgy parts have long been an important part of engineering (mostly sintered bronze bushings impregnated with grease), and have recently become hugely common as powder gears.

Manufacturing standard spur gears in particular has benefited HUGELY from powder metallurgy. You can use it to make exceptionally accurate and cheap extrudable shapes, and gears have traditionally been hugely expensive and wasteful because you have to cut out the teeth, harden, and final-cut. Powder metallurgy has created an important middle ground- exceptionally cheap medium-quality gears. Now instead of unhardened gears you will always get powder gears, which are better. In places where final-ground gears were overkill, powder gears have come in at acceptable quality and greatly reduced prices. Powder metallurgy is awesome!

[yetihehe]

> Now instead of unhardened gears you will always get powder gears, which are better.

Nope, now instead of unhardened gears you get powder gears which are even worse (but much cheaper than those good powder gears), but minimally better than plastic. My father is power tools' serviceman and since sintered gears became more common, there are MUCH more broken transmissions (but yeah, they are a little cheaper).