Surface coating of Be-Cu bottle cap die and preparation method of surface coating

The invention discloses a surface coating of a Be-Cu bottle cap die and a preparation method of the surface coating, and relates to the technical field of coating preparation. The method comprises steps as follows: a first coating and a second coating are prepared on a Be-Cu bottle cap die substrate by magnetron sputtering under the low-temperature condition in sequence; and then, a third coatingis deposited on the second coating with a PECVD technology under the low-temperature condition, wherein the first coating is a Cr/CrN/CrCN/CrC coating or a Ti/TiN/TiCN/TiC coating, the second coatingis a WCC coating, and the third coating is a DLC coating. According to the method, the DLC coating is deposited with the PECVD technology under the low-temperature condition, and a rubber sealing ringin a bottle cap die cannot be affected, so that the service life of the Be-Cu bottle cap die can be prolonged. Meanwhile, the deposited DLC coating has the characteristics of small internal stress, high binding force, high har