That is not a problem because WS2 is completly inert material.
Chemical Durability: Inert Substance, Non-Toxic
Magnetism: Non-Magnetic
Rockwell Hardness: 30 HRc
Coating Film Thickness: up to 0.5 micron depending on application
Corrosion Stability: Can slow down the corrosion rate, but can not fully prevent substrate corrosion
Coatable Substrates: Iron, Steel, Aluminum, Copper, other Metals, Plastics and Manmade Solids (ceramics)
Compatibility: Oil, Solvent, Paint, Fuel, Water