Ti-Cu-N Hard Nanocomposite Films Prepared By Ion Beam Assisted Deposition

The structures and corresponding mechanical properties of Ti-Cu-N nanocomposite films synthesized by ion beam assisted deposition on the matrix of SS and HSS were studied in this paper. The influences of ion bean discharge current and substrate bias voltages on chemical compositions, structures, morphology, hardness and elastic modulus of the films were examined with X-ray photoelectron spectroscopy(XPS), X-ray diffraction(XRD), scanning electron microscope(SEM), Transmission electron microscopy(TEM) and Nano indentation apparatus. The influences of process parameters on the structures and properties of the films were analyzed.The results showed that the content of Cu in Ti-Cu-N nanocomposite films on SS substrate increased firstly and then decreased between 1.47 at.% and 2.75 at.% when the bias voltages increased and the ion beam energy was constant. The minimum value of Cu content was 1.47 at.% was obtained at the bias voltage of-600 V. Meanwhile, the preferred orientation changed from Ti N(111) to Ti N(220). Ti N at all bias voltages had face-centered cubic structures(B1-Na Cl). Cu2 p peaks of the film corresponded to pure metal Cu. The average grain size changes between 11 nm and 16 nm. The hardness decreased when the bias voltages increased. The maximum values of the hardness was 27.2 GPa while the bias voltage was-100 V.The content of Cu in Ti-Cu-N nanocomposite films on HSS substrate appeared to be in the range of 1.05-2.50 at.% when the bias voltages changed from-100 V to-900 V. Meanwhile, the films exhibited a preferred orientation Ti N(111) texture when the substrate bias voltages were-100 V. The preferred orientation changed to be Ti N(220) when the substrate bias voltages increase to-300 V to-900 V. Cu2 p peaks of the films corresponded to pure metal Cu, and the average grain size changed between 11 nm and 17 nm. The value of the hardness and elasticity modulus increased when the bias voltages increased,and the maximum values were 29.92 GPa and 476 GPa were obtained while the bias voltage was-900 V.The content of Cu in Ti-Cu-N nanocomposite films on SS substrate appeared to be in the range of 1.19-1.80 at.% at the bias voltage-600 V when the discharge current changed from 10 A to 40 A. The films on SS substrate exhibited only a preferred orientation Ti N(220) texture when the discharge currents were 10A-40 A. Cu2 p peaks of the films correspond to pure metal Cu. The value of the hardness and elasticity modulus changed when the discharge current increased. The maximum values of the hardness and elasticity modulus were 39.73 GPa and 535.85 GPa respectively at discharge current of 10 A. Meanwhile, the corresponding content of Cu was 1.50 at.%.The content of Cu in Ti-Cu-N nanocomposite films on HSS substrate changed from 1.14 at.% to 1.55 at.% at the bias voltage-600 V when the discharge current changed. The films exhibited a preferred orientation Ti N(220) texture when the discharge current were in the range of 10A-40 A. The SEM morphologies showed that the amount of macroparticles(MPs) on the surface of the films decreased when the discharge current increased. With the discharge current increased, the hardness of the films increased firstly and then decreased. The hardness and elasticity modulus of the films reached the maximum 39.24 GPa and 544.59 GPa at the discharge current of 30 A, while the content of Cu was 1.16 at.%.