Britannica Sources used in this answer

Why are powder-metallurgy methods used to make cemented tungsten carbide tools?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Diagram of a zinc-lead blast furnace system showing ore and coke entering through charge hoppers, with labeled furnace, air preheater, blower, taphole for slag and lead bullion, and a connected lead-splash condenser using rotors to separate and cool lead and zinc, with pathways for molten metals and off-gas. — metallurgy A zinc-lead blast furnace and lead-splash condenser. This technology is utilized mainly for producing zinc while managing both lead and zinc from raw materials, a technique that was highly influential in 20th-century smelting.

Powder-metallurgy methods are essential for producing cemented carbides because they allow for the creation of composite structures that balance extreme hardness with necessary toughness.12

Pure tungsten carbide is an exceptionally hard compound, but it is too brittle to be used effectively in industrial tools. Furthermore, tungsten carbide has an extremely high decomposition temperature (2,600° C), making traditional casting impractical.13

To overcome these limitations, manufacturers use powder metallurgy to:
* Create a Composite: Tungsten carbide powder is mixed with a binder metal, typically cobalt.32
* Sintering: The mixture is pressed into a desired shape and heated to a temperature above the melting point of the cobalt.314
* Bind the Material: The liquid cobalt wets and partially dissolves the tungsten carbide grains. Upon cooling, the cobalt freezes, acting as a cement that holds the hard carbide particles together.31

This process results in a material with the toughness and shock resistance required for practical applications such as machine tools, drill bits, dies, and saws.14