Dry cutting is one prospect new technology in the field of machining.But dry cutting technology puts forward a higher requirement for hardness and wearability at high temperatures and thermal stability.In order to find improved coatings for dry machining operations,the quaternary Cr-Ti-Al-N composite coating synthesized by multi-arc ion plating technology in a gas mixture of At+N2.The structural and mechanical properties of the coatings were characterized using X-ray diffraction (XRD) and nanoindentation techniques,respectively.The bonding structure of the coatings was characterized by X-ray photoelectron spectroscopy (XPS).The surface morphology of the coatings was studied using scanning electron microscopy (SEM).And the tribological properties and cutting performance of CrTiAlN composite films were compared with the industrially coated TiN and TiAlN carbide tools.The experimental results showed that the optimised quaternary Cr-Ti-Al-N coating performs better than the binary TiN as well as the ternary Ti-Al-N coatings in terms of hardness and wear resistance.The introduction of both Cr and Al elements into the TiN-based coatings enhances both of their mechanical and tribological performance.And the sequence of cutting life for these coated tools were CrAITiN>TiAlN>TiN.The research results revealed that the composite coated tools have remarkable advantages in tools life.