PURPOSE: To obtain an Al alloy coated W material excellent in high temp. corrosion resistance and the adhesion of an Al coated layer by subjecting a metallic tungsten base material of high purity and low oxygen with an Al-W alloy having a specified thickness.

CONSTITUTION: A metallic tungsten base material having ≥99.9% purity and <0.02% oxygen content is coated with an Al-W alloy having 60 to 120um thickness. The W base material can be obtd. by subjecting W powder having ≥99.9% purity, <0.02% oxygen content and about 0.2 to 5um grain size, e.g.,obtd. by reducing ammonium paratungstate to compacting, sintering, forging or the like. This W base material is subjected to heat treatment at 1000 to 1500°C for about 3 to10hr in H2 to uniformize the structure and to remove stress, and after that, it is coated with Al by a hot-dip Al plating method or the like. Next, the Al plated W material is subjected to heat treatment at about 400 to 600°C in an oxidizing atmosphere. By this thermal cementation, Al is diffused into the W base material to obtain the prescribed Al alloy coated W material.