Tool with chromium-containing functional layer

Cutting tool including a substrate of hard metal carbide, cermet, steel or high-speed steel (HSS) and a multi-layer coating deposited thereon by a PVD process, wherein starting from the substrate the multi-layer coating comprises the following sequence of layers:

• a) a base layer consisting of one or more identical or different layers arranged one on top of another of a nitride or carbonitride and which contains at least aluminium (Al) and optionally one or more further metals selected from Ti, Cr, Si, Y, Ru and Mo,
• b) an intermediate layer arranged on top of the base layer and consisting of one or more oxides or oxynitrides of the metals Al, Cr, Si, and/or Zr, the intermediate layer exhibiting a cubic structure, and
• c) a chromium-containing functional layer arranged on top of the intermediate layer and selected from chromium oxide (Cr2O3), chromium oxynitride, aluminium-chromium oxide (AlCr)2O3, aluminium-chromium oxynitride or a mixed oxide or mixed oxynitride of aluminium, chromium and further metals (AlCrMe1, . . . Men)2 oxide or (AlCrMe1, . . . Men)2 oxynitride, in which Me1, . . . Men means one or more further metals selected from Hf, Y, Zr and Ru, the functional layer exhibiting a rhombohedral structure.