| http://www.w3.org/ns/prov#value | - Preferably, at least a portion of the drilling bit 10 is coated with a coating material 16, one of the group of materials including, for example, diamond-like carbon (DLC) coating, a ceramic coating, a tungsten carbide coating, a titanium nitride coating, an aluminum titanium nitride coating, tungsten disulfide coating, or other similar materials such as diamond dust particulates or a combination
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