TiSiCN Coatings Research Articles

Microstructure and Mechanical Properties of Ti(Cr)SiC(O)N Coatings Deposited by Plasma Enhanced Magnetron Sputtering

TiSiCN, TiSiCON, TiCrSiCN, TiCrSiCON, CrSiCN and CrSiCON coatings have been deposited on WC-Co substrates and Si wafers using plasma enhanced magnetron sputtering (PEMS) technique. The microstructure, composition and mechanical properties of the non-oxygen coatings and oxygen-containing coatings were studied by XRD, SEM, EDS and load-depth-sensing indentation. The tribological behavior of the coatings against Al 2 O 3 balls was conducted by pin-on-disc tests. The results show that TiSiCON, TiCrSiCON and CrSiCON coatings exhibit the face center cubic (fcc) TiN-type (or CrN-type) structure. The existence of oxygen will induce loose structure and more defects for TiSiCON, TiCrSiCON and CrSiCON coatings compared with TiSiCN, TiCrSiCN and CrSiCN, respectively. The addition of oxygen element would lead to the decrease of the hardness ( H ) and elasticity of Ti(Cr)SiCN coatings. TiCrSiCON and CrSiCON coatings with oxygen element have lower friction coefficients and wear rate compared with TiCrSiCN and CrSiCN coatings without oxygen, respectively. The TiSiCON with higher friction coefficient and wear rate shows poor abrasive wear resistance than TiSiCN.

Influence of bias voltage on structure and tribocorrosion properties of TiSiCN coating in artificial seawater

The TiSiCN coatings deposited at different bias voltages were fabricated on Ti6Al4V alloy by arc ion plating. The structure and properties of the TiSiCN coating were characterized using scanning electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, nanoindentation, potentiostat and ball-on-plate wear tests. As the bias voltage increases, the TiSiCN coating shows a nanocrystallite/amorphous structure, whereas the phase constitution and grain size changed slightly, and its hardness and tribocorrosion properties also change correspondingly. When the bias voltage is −100V, the coating has a composite structure of typical nanocrystallite/amorphous, and a small amount of MAX phase of Ti3SiC2. Moreover, the protection potential applied on the coating effectively prevents the electrochemical corrosion of the coating. However, the applied protection potential will accelerate the degradation of the coating when the channel formed between the surface of the wear track and substrate.

Influence of carbon contents on the structure and tribocorrosion properties of TiSiCN coatings on Ti6Al4V

The TiSiCN coatings were fabricated on Ti6Al4V. The effect of carbon contents on the structure and tribocorrosion properties were studied. The coatings consist of TiN, TiC and Ti(C,N) nanocrystallites, amorphous Si3N4, SiC and little amorphous carbon. The coating (11.9at% C) exhibits maximum hardness of 39.8GPa and the best tribocorrosion resistance, which is attributed to the special nanocomposite structure, and the lower friction coefficient of the TiSiCN coating associated with the graphitization effect during sliding in atmosphere. Moreover, the results of tribocorrosion indicate that the volume loss of TiSiCN coatings ascribed to main wear loss and a little corrosion loss, and the synergy between wear and corrosion is a key factor in degenerating the TiSiCN coating.

Development and evaluation of low friction TiSiCN nanocomposite coatings for piston ring applications

Abstract To minimize the frictional losses and wear of piston rings in an automotive engine, thick low friction TiSiCN nanocomposite coatings have been developed. The coatings were deposited by sputtering titanium targets in argon, nitrogen, hexamethyldisilazane (HMDSN), and acetylene (C 2 H 2 ) using plasma enhanced magnetron sputtering (PEMS). The substrates were AISI 304 stainless steel coupons and piston rings with bore diameters of 137 mm and 86 mm. The elemental composition and microstructure of the coatings were optimized by varying the HMDSN and C 2 H 2 flow rates separately to achieve a combination of excellent adhesion, good mechanical properties, low coefficient of friction (COF) and wear rate. The optimized TiSiCN coatings exhibited a typical nanocomposite structure which showed excellent adhesion and dry COF in the range of 0.17 to 0.2 using a ball-on-disk tribometer. The tribological performance of the coated piston rings was evaluated using Plint TE77 tests in SAE 10W-30 diesel engine oil. The TE77 tests showed a 10% reduction in the COF (0.058) of the optimized coating compared to the uncoated baseline (0.065) at test conditions of 20 Hz, 30 N, and 25 mm stroke length. Finally, the coated rings were evaluated in a single cylinder gasoline engine using SAE 5W-20 engine oil and in a heavy duty diesel engine using 4.1% sooted SAE 10W-30 diesel engine oil. The gasoline engine test showed that the uncoated piston rings contributed 25% to 34% of the frictional loss in two separate baseline engine tests. In contrast, the coated rings contributed to 18% of the total frictional loss in the engine test. The diesel engine durability test showed a 28% and 40% lower ring weight loss for the coated top and second rings, respectively, as compared to the uncoated baseline. In addition, the cylinder liner, which was not coated, showed an average 50% lower wear than that in the uncoated baseline engine test.

Tribological behavior of TiN and Ti (Si,C)N coatings on cold sprayed Ti substrates

Abstract The evolution of the cold spray technology in the aerospace part repair created a need to better understand the mechanical and tribological behavior of the protective coatings on the cold sprayed repair. For that purpose, a bi-layer system consisting of titanium cold spray coating on a commercially available titanium substrate and TiN, TiSiN and TiSiCN HiPIMS protective coatings were produced. The mechanical and tribological behavior of the coatings was evaluated under reciprocating wear with a reciprocating tribometer equipped with an aluminum ball (4 mm in diameter) counterface. The wear tracks were analyzed with a light interferometer. A cross-sectional analysis of the wear track was performed with SEM following focused ion beam milling. Focused ion beam milling revealed the deformation induced damages to the coatings. Cold sprayed substrate porosity, grain refinement and hardness were shown to play a significant role on the wear characteristics of HiPIMS deposited TiN, TiSiN and TiSiCN coatings.

Effects of Zr, Nb, or Si addition on the microstructural, mechanical, and corrosion resistance of TiCN hard coatings

Stoichiometric TiZrCN, TiNbCN, and TiSiCN coatings, with Zr, Nb, or Si as alloying elements, were deposited on Si and M2 high speed steel substrates by the cathodic arc technique in a mixture of N2 and CH4 gases. Coatings with a C/N ratio value of about 0.5 have been prepared and comparatively investigated for elemental and phase composition, texture, adhesion, and anticorrosive properties. All coatings consisted of fcc solid solutions, with an (111) preferred orientation. The addition of either Zr, Nb, or Si in the basic structure of TiCN coatings resulted in adhesion enhancement (critical loads in the range 20–30 N) and increased corrosion resistance, as tested in 3.5% NaCl solution.

Effects of Al and V Additions on Mechanical Response in Thick TiSiCN Nanocomposites Deposited Using Plasma-Enhanced Magnetron Sputtering

Thick TiSiCN and TiAlVSiCN nanocomposite coatings were fabricated by plasma-enhanced magnetron sputtering (PEMS). Characterizations by electron probe microanalyzer (EPMA) and XRD revealed the dependence of films with various precursor flow rates on the constituent composition and structure evolution in coatings. HRTEM images clearly confirmed that a nanocomposite structure existed with grain size below 10 nm. It was believed that nanocrystalline TiCxN1-x-based phases with B1 structure were embedded in an amorphous SiCyNz matrix, and such phase segregation ameliorated the hardness and H/E ratios. In the scratch and ball-on-disc wear tests, the evidence from crack initiation resistance, friction coefficient, and worn surfaces verified that thick nanocomposites exhibited remarkable tribological resistance. Hybrid anti-wear mechanisms on the basis of mechanical property variation, composition distribution, and microstructure evolution were proposed to elucidate the favorable durability of these thick films.

Comparative study of electrochemical and impact wear behavior of TiCN, TiSiCN, TiCrSiCN, and TiAlSiCN coatings

The aim of this work was to investigate the electrochemical and repetitive impact wear behaviors of Cr- and Al-doped TiSiCN coatings in comparison with their TiCN and TiSiCN counterparts. The coatings were deposited by reactive DC magnetron sputtering of TiC, TiSiC, TiCrSiCN, and TiAlSiCN targets in a gaseous mixture of Ar+15%N2. The structure, elemental and phase compositions of coatings were studied by means of X-ray diffraction, scanning electron microscopy, and glow discharge optical emission spectroscopy. The coatings were characterized in terms of their hardness, elastic modulus, elastic recovery, and adhesion strength. To evaluate their electrochemical characteristics, the coatings were tested in 1N H2SO4 and 0.9% NaCl solutions. The coatings were also subjected to a range of impact tests, first in air, and then in normal saline (to assess a tribocorrosion effect) and distilled water (to assess a hydrodynamic effect in liquid). The obtained results show that all the coatings, except the TiCN, exhibit similar mechanical properties but their failure modes (plastic deformation, brittle fracture or their combinations) during scratch tests are markedly different. The poorest dynamic impact performance of the TiCN coating in air, distilled water, and NaCl solution was attributed to both the imperfection of coating structure (micro-chips and “pin-holes”) and reduced mechanical properties. Although the TiSiCN coating possessed the highest hardness, its high wear led to a reduced impact resistance. The Cr-doped TiSiCN coating performed well in air, but rapidly failed during dynamic impact tests in normal saline due to corrosion reactions. The TiAlSiCN coating was the only one which sustained repetitive impact load for 105cycles in air (maximal normal load of 1000N), as well as in distilled water (neutral medium) and normal saline (corrosive medium) at 500N.

Ternary and quarternary TiSiN and TiSiCN nanocomposite coatings obtained by Chemical Vapor Deposition

TiN and TiCxNy are commercial CVD coatings widely used for cutting tools. A promising route for improving their performance is the addition of silicon. Therefore the main objective of this work is the preparation of TiSiN and TiSiCN coatings with a nanocomposite structure offering a higher hardness as well as an improved oxidation and wear resistance. New low pressure CVD processes in the range 800°C–900°C were developed for the successful deposition of nanocomposite coatings of TiSiN and TiSiCN on hard metal substrates. TiSiN nanocomposites are obtained with a mixture of the precursors TiCl4, SiCl4 and NH3 whereas for TiSiCN coatings acetonitrile is added instead of NH3. In this work microstructure, composition, properties and oxidation behavior of the nanocomposite coatings were investigated. TiSiN coatings consist of the crystalline phases TiN, Ti5Si3 and amorphous silicon nitride. The hardness correlates well with silicon content and crystallite size. A maximum hardness of about 3700 HV[0.01] was observed at a silicon content between 6at.% and 8at.% and a TiN crystallite size about 15nm. TiSiCN coatings prepared with the acetonitrile process exhibit a nanocomposite structure of nanocrystalline TiCxNy and amorphous SiCxNy. Compared to TiSiN a still higher hardness up to 4100 HV[0.01] was measured for a silicon content of 11.7at.%. TiSiN coatings with a silicon content between 5.5 and 7.7at.% offer an oxidation resistance up to 700°C. But TiSiCN with 2.2at.%–11.7at.% silicon is even more stable up to 900°C. At these temperatures TiO2 is formed at the surface.The examination of the adherence showed that a diffusion barrier is necessary for suppressing the cobalt diffusion from cemented carbide substrate into the layers. If interlayers of TiN or TiCxNy were applied critical loads of 80N for TiSiN and 43N for TiSiCN coatings were obtained by scratch tests.

Synthesis and characterization of Ti–Si–C–N nanocomposite coatings prepared by a filtered vacuum arc method

Ti–Si–C–N nanocomposite coatings were synthesized by a filtered vacuum arc (FVA) technique. A metal organic precursor, tetramethylsilane (TMS), was used as a source for silicon and carbon to deposit the Ti–Si–C–N nanocomposite coating with a Ti cathode source. The chemical and microstructural properties of the as-deposited coatings were systematically investigated using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Nanoindentation and scratch tests were carried out to evaluate the mechanical and adhesion properties of the coatings. From the XPS analysis, it was found that the Si content in the coating increased from 2 to 16at.% as the TMS flow rate was increased from 5 to 20sccm. The TEM analysis clearly demonstrated that the coatings were composed of crystalline TiCN along with amorphous Si3N4 as a secondary phase. From the XRD results, it was found that the crystallite size of TiCN increased with increasing Si content. The microstructure and mechanical properties of the TiSiCN coatings prepared by this method exhibited strong dependencies on the silicon content. A maximum hardness of 49GPa and a coefficient of friction of 0.17 were obtained for the film with a silicon content of 3at.%.

Evaluation of mechanical properties of Ti(Cr)SiC(O)N coated cemented carbide tools

In order to enhance the life of cemented carbide tools for milling Ti6Al4V alloy, Ti(Cr)SiC(O)N (including TiSiCN, TiSiCON, CrSiCN and CrSiCON) coatings were deposited on flat samples for characterization and K40UF cemented carbide end-mills for milling tests. The adherence strength of the coatings was determined using scratch tests. Wear tests were carried out using a ball-on-disk tribometer with Ti64 balls without lubricant. Dry milling tests of the coated end-mills were carried out on the Ti64 alloy at a 45 m/min cutting speed. The results indicated that the Cr-based coatings (CrSiCN and CrSiCON) have a better adherence strength and toughness than the Ti-based coatings (TiSiCN and TiSiCON). The CrSiCN and CrSiCON coatings had a lower friction coefficient than the TiSiCN and TiSiCON coatings, while the TiSiCN and TiSiCON coatings had a lower wear rate than the CrSiCN and CrSiCON coatings. The milling test results showed that TiSiCN and CrSiCN coated tools had a better cutting performance than TiSiCON and CrSiCON coated ones.

Microstructure and tribological properties of Ti(Cr)SiCN coating deposited by plasma enhanced magnetron sputtering

Three kinds of hard coatings, TiSiCN, TiCrSiCN and CrSiCN were deposited on WC/Co alloys by plasma enhanced magnetron sputtering (PEMS) technique. Those coatings were comparatively studied with respect to their microstructure and mechanical properties. The sliding tribological behaviour of the coatings against Ti6Al4V counterpart was also studied by pin-on-disc tests. The results indicated that TiN and CrN were the main phase composition for the TiSiCN and CrSiCN coatings, respectively. While the TiCrSiCN coating consisted of TiCrN2 phases or Cr be incorporated in TiN as a single solid solution. The TiCrSiCN coating showed higher hardness than the CrSiCN coating, better adhesion with substrate than the TiSiCN coating, and higher dry sliding wear resistance against the Ti6Al4V counterpart than both TiSiCN and CrSiCN coatings.

Comparative investigation of Al- and Cr-doped TiSiCN coatings

The aim of this work was a comparative investigation of the structure and properties of Al- and Cr-doped TiSiCN coatings deposited by magnetron sputtering of composite TiAlSiCN and TiCrSiCN targets produced by self-propagating high-temperature synthesis method. Based on X-ray diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy data, the Al- and Cr-doped TiSiCN coatings possessed nanocomposite structures (Ti,Al)(C,N)/a-(Si,C) and (Ti,Cr)(C,N)/a-SiCxNy/a-C with cubic crystallites embedded in an amorphous matrix. To evaluate the thermal stability and oxidation resistance, the coatings were annealed either in vacuum at 1000, 1100, 1200, and 1300°C or in air at 1000°C for 1h. The results obtained show that the hardness of the Al-doped TiSiCN coatings increased from 41 to 46GPa, reaching maximum at 1000°C, and then slightly decreased to 38GPa at 1300°C. The Cr-doped TiSiCN coatings demonstrated high thermal stability up to 1100°C with hardness above 34GPa. Although both Al- and Cr-doped TiSiCN coatings possessed improved oxidation resistance up to 1000°C, the TiAlSiCN coatings were more oxidation resistant than their TiCrSiCN counterparts. The TiCrSiCN coatings showed better tribological characteristics both at 25 and 700°C and superior cutting performance compared with the TiAlSiCN coatings.