Can tungsten be used to coat a geospherical drill?

Question

...most drills used to bore into the earths crust are coated in iron, so that they do not collapse from the pressure or melt from the heat. Now tungsten is a metal with a higher melting point than iron, so could it replace it as a coating for the drills, and be more effective?

Answer 1

Titanium is the hardest material now in use for coating of cutting tools.

Answer 2

most deep drill bits are made from either specially hardened steel or are tungsten-carbide coated.

No one has really come close to drilling at a depth where a molten drill bit would be an issue.