Nanometer composite structure protective coating made from high hardness CrAlSiN and preparation method of nanometer composite structure protective coating

The invention relates to a nanometer composite structure protective coating made from high hardness CrAlSiN and a preparation method of the nanometer composite structure protective coating. The preparation method comprises the following steps: (1) cleaning matrixes, and then performing ion cleaning; (2) preparing a CrN transition layer: sending the matrixes processed in the step (1) to a sputtering chamber, so that the CrN transition layer is deposited, a Cr target material is controlled by a direct current cathode, and a 200-300nm CrN transition layer is deposited; and (3) preparing a CrAlSiN layer, wherein a CrAlSi composite target material is controlled by a radio frequency cathode, and 2-4 mum of a CrAlSiN nanometer composite coating is deposited on the surface of the CrN transition layer. The coating not only has high hardness of 43.6GPa, but also has excellent high-temperature oxidation resistance and excellent corrosion resistance, so that the protective coating disclosed by the invention can be used as a protecting coating for a high-speed dry cutting cutter and equipment with high loads in other fields. The preparation method has the characteristics of simple technology, high deposition speed, low cost, high bond strength and the like, and has the advantages of high production efficiency, low energy consumption, low equipment requirements, and the like.