Patent ID: 8025956

Claim:
A hard film, comprising: (M) a Cr b Al c Si d B e Y f Z, wherein: M is at least one element selected from the group consisting of a group 4A element, a group 5A element, and a group 6A element (except for Cr) in the periodic table, Z is one of N, CN, NO and CNO, a, b, c, d, e and f are atomic ratios of M, Cr, Al, Si, B and Y respectively, a+b+c+d+e+f= 1, and a, b, c, d, e and f are one of following 1), 2) and 3): 1) 0<a≦0.3, 0.05≦b≦0.4, 0.4≦c≦0.8, 0.03≦d≦0.2, 0≦e≦0.2, and 0.01≦f≦0.1, 2) 0<a≦0.3, 0.05≦b≦0.4, 0.4≦c≦0.8, 0≦d≦0.2, 0.03≦e≦0.2, and 0.01≦f≦0.1, and 3) 0<a≦0.3, 0.05≦b≦0.4, 0.4≦c≦0.8, 0.03≦d≦0.2, 0.03≦e≦0.2, and 0.01≦f≦0.1.