| 摘要 |
A coated cutting tool 20 comprises a substrate 21 and a coating 22 comprising a refractory layer deposited by physical vapour deposition (PVD) adhered to the substrate, the refractory layer comprising M1-xAlxN, wherein M is Ti, Cr or Zr. In a first aspect, x ≥ 0.68, and the refractory layer includes a cubic crystalline phase and has a hardness of at least 25 GPa. In a second aspect, x ≥ 0.55, and the refractory layer has a thickness greater than 5 µm, a hardness of at least 25 GPa and a compressive stress less than 2.5 GPa. In a third aspect, a method of making the tool is disclosed, wherein x ≥ 0.64, the refractory layer has a cubic crystalline phase and a hardness of at least 25 GPa, and wherein the coating is deposited with a cathodic arc deposition apparatus comprising at least one anode (44, fig 4) having an annular extension. The coating 22 is formed of a refractory layer 23 which may comprise a single layer of M1-xAlxN, or may have a plurality of sublayers 24 which may be stacked in an alternating pattern (as shown). In one arrangement an intermediate layer (37, fig 3) may be provided between the substrate (31, fig 3) and the refractory layer (33, fig 3), the intermediate layer comprising either a single layer or multiple layers and improving adhesion of the refractory layer to the substrate. |
