Patent ID: 7695829

Claim:
A hard coating film to be applied to the surface of a tool, said hard coating film comprising layers A and layers B which are placed alternately one over another, wherein each of said layers A has a composition represented by the formula Al 1-a-b Si a Mg b (B x C y N Z ), where a, b, x, y, and z represent atomic ratios such that 0≦a≦0.35, 0≦b≦0.2, 0.03≦a+b≦0.5, 0≦x≦0.2, 0≦y≦0.4, 0.5≦z≦1, and x+y+z=1; each of said layers B has a composition represented by the formula Ti 1-m-n Cr m Al n (B o C p N q ), where m, n, o, p, and q represent atomic ratios such that 0≦m≦0.5, 0.5≦n≦0.75, 0≦1-m-n ≦0.5, and o+p+q=1; and each of said layers A and layers B has a thickness not smaller than 2 nm and not larger than 200 nm.