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Diamond powder is finely granulated diamond that is often used to make drill bits and abrasives, and acts as an alloying ingredient with metals. Diamond is one of the strongest known substances on Earth, making diamond powder popular for industrial purposes. Most mined diamonds and nearly all synthetic diamonds are made into diamond powder, because they are not lustrous enough or colorful enough to be valuable as gemstones. While powdered diamond is strong, it is worn away when used at high speeds on iron alloys.
Considered to be one of Earth’s strongest substances, diamonds are generally thought of as gemstones, but this often is not how most diamonds are used. When diamonds are mined, they are checked for color, clarity and luster to see if they are valuable as gems. Gemstone-quality diamonds are professionally cut and polished; the rest are sent to refineries that pulverize them into diamond powder.
Most naturally mined diamonds — around 80 percent — are used for industrial purposes. Synthetic diamonds that mimic the strength of natural diamond can be created under high-temperature, high-pressure conditions. These synthetic diamonds are largely used to create diamond powder. Around 80 percent to 90 percent of all industrial diamonds are synthetic, because they are cheaper to purchase, and they are rarely valued as gemstones because they are not naturally created.
Being so strong, one of the major uses of diamond powder is in the creation of abrasives. An abrasive is a substance, such as sandpaper, that is rubbed against another substance, such as wood, to wear away a few layers of the second substance. This makes the second substance smooth or coarse, depending on the abrasive’s design.
Another major use of diamond powder is in the creation of tools, such as drill bits. To make these, powdered diamond is generally added to a molten pool of metal, spreading flecks of diamond throughout the metal. When the metal is cast into a tool shape, the diamond powder will remain in the metal, making it stronger.
While diamond is strong, powdered diamond machining tools are not good when used against iron alloys at high speeds. This is because the high speed creates a reaction between the iron and the carbon in the diamond, making the carbon soluble to the iron. The result is that the diamond will wear very quickly, making it difficult to maintain.