Tantalum Coating for High Temperature

Q: I’m interested in TZM or Tantalum fasteners and was also wondering if there was an option to have the fasteners coated to increase the use temperature in air?

A: There really is not a coating that could be used for tantalum and molybdenum screws to increase their life in an O2 environment. The typically Molybdenum Disilicides which are used throughout industry are too thick for the threading and very brittle. They would not work well on fasteners. In air Tantalum has the maximum temperature limit of 572°F.