Apparatus and systems are disclosed for providing a protective material for a gas-delivery system of a processing system. In an embodiment, a processing system includes a processing chamber for processing substrates and a gas-delivery system for delivering processing gases to the processing chamber. The gas-delivery system includes a protective material to protect the gas-delivery system from processing gases including at least one processing gas heated to an elevated temperature. The protective material includes a tungsten plate or a tungsten plate coated with a tantalum alloy and tantalum