Corrosion resistance of W and Ta based amorphous coatings in a geothermal steam environment – A combinatorial study

•WSi and TaSi are amorphous in a large composition range when prepared by sputtering.•TaSi amorphous coatings are highly corrosion resistant in geothermal steam.•WSi amorphous coatings undergo severe corrosion in geothermal steam.•Combinatorial methods are extremely efficient in screening for corrosion resistance.