Low-temperature growth of low friction wear-resistant amorphous carbon nitride thin films by mid-frequency, high power impulse, and direct current magnetron sputtering

Abstract

Low-temperature growth of low friction wear-resistant amorphous carbon nitride thin films by mid-frequency, high power impulse, and direct current magnetron sputtering, Journal of Vacuum Science & Technology. A, 2015, 33(5) The potential of different magnetron sputtering techniques for the synthesis of low friction and wear resistant amorphous carbon nitride (a-CN x ) thin films onto temperature-sensitive AISI52100 bearing steel, but also Si(001) substrates was studied. Hence, a substrate temperature of 150 C was chosen for the film synthesis. The a-CN x films were deposited using mid-frequency magnetron sputtering (MFMS) with an MF bias voltage, high power impulse magnetron sputtering (HiPIMS) with a synchronized HiPIMS bias voltage, and direct current magnetron sputtering (DCMS) with a DC bias voltage. The films were deposited using a N 2 /Ar flow ratio of 0.16 at the total pressure of 400 mPa. The negative bias voltage, V s , was varied from 20 to 120 V in each of the three deposition modes. The microstructure of the films was characterized by high-resolution transmission electron microscopy and selected area electron diffraction, while the film morphology was investigated by scanning electron microscopy. All films possessed an amorphous microstructure, while the film morphology changed with the bias voltage. Layers grown applying the lowest substrate bias of 20 V exhibited pronounced intercolumnar porosity, independent of the sputter technique. Voids closed and dense films are formed at V s ! 60 V, V s ! 100 V, and V s ¼ 120 V for MFMS, DCMS, and HiPIMS, respectively. X-ray photoelectron spectroscopy revealed that the nitrogen-to-carbon ratio, N/C, of the films ranged between 0.2 and 0.24. Elastic recoil detection analysis showed that Ar content varied between 0 and 0.8 at. % and increased as a function of V s for all deposition techniques. All films exhibited compressive residual stress, r, which depends on the growth method; HiPIMS produces the least stressed films with values ranging between À0.4 and À1.2 GPa for all V s , while CN x films deposited by MFMS showed residual stresses up to À4.2 GPa. Nanoindentation showed a significant increase in film hardness and reduced elastic modulus with increasing V s for all techniques. The harder films were produced by MFMS with hardness as high as 25 GPa. Low friction coefficients, between 0.05 and 0.06, were recorded for all films. Furthermore, CN x films produced by MFMS and DCMS at V s ¼ 100 and 120 V presented a high wear resistance with wear coefficients of k 2.3 Â 10 À5 mm 3 /Nm. While all CN x films exhibit low friction, wear depends strongly on the structural and mechanical characteristics of the films. The MFMS mode is best suited for the production of hard CN x films, although high compressive stresses challenge the application on steel substrates. Films grown in HiPIMS mode provide adequate adhesion due to low residual stress values, at the expense of lower film hardness. Thus, a relatively wide mechanical property envelope is presented for CN x films, ...

A comparative study of direct current magnetron sputtering and high power impulse magnetron sputtering processes for CNx thin film growth with different inert gases

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A new slurry infiltration method to enhance the wear resistance of bulk graphite with development of reinforced graphitic composites including SiC or Si3N4 hard particles

“…The significant increase of the hardness of the composites compared to the reference graphite sample can be attributed to the increased density and decreased porosity of the composites after the infiltration (Table II) [44]. This is a result of the deposition of hard SiC and Si3N4 particles in the pores of the soft graphitic matrix, contributing to the measured hardness values, which is confirmed by the relatively high errors of the measurements.…”

Research on Magnetron Sputtering CNx Films Process Based on Orthogonal Experimental Design

“…The results show that the surface roughness Sa range from 3.32 nm to 44.6 nm. (2) Orthogonal experiment was arranged to analyze the process parameters. The results show that the parameters affect the film surface roughness in the following orders: nitrogen pressure, duty ratio, target current and bias voltage according to range analysis and visual analysis.…”

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