Cr-B-N films were synthesized by unbalanced magnetron sputtering from a sintered Cr-B target with 20 at% B in an Ar-N-2 discharge at varying N-2 partial pressures (p(N2)) of up to 64% of the total pressure (P-Ar + P-N2 = 0.4 Pa). Coating composition and microstructure were investigated by X-ray diffraction, X-ray photoelectron spectroscopy and wavelength-dispersive electron-probe microanalysis and correlated with mechanical and tribological properties measured by microindentation and dry sliding ball-on-disk tests. For low nitrogen partial pressures (P-N2 <= 22%), the XRD patterns are composed of broad overlapping peaks with low intensity. These films have hardness values of similar to 15 GPa and indentation moduli of similar to 150 GPa. Increasing p(N2) from 22% to 28% results in an increase of the N content from similar to 38 to 50 at% where the films meet the quasi-binary CrN-BN composition. Thereby, an increase of the hardness from similar to 15 to 32 GPa is obtained. A further increase in P-N2 up to 64% results in minor changes of the chemical composition, micro and bonding structure as well as mechanical properties. While in ball-on-disk testing early failure was observed for coatings grown at P-N2 <= 22%, higher nitrogen contents in the discharge yielded friction coefficients of similar to 0.43 independent of chemical composition, microstructure and mechanical properties.