CrN Interlayer Research Articles

Micromechanical investigation of DLC based coating systems by means of combined characterization and simulation methods

The assessment of the elastic-plastic material behavior is imperative for benchmarking the performance of thin coating systems. Linear-elastic approaches can lead to deviating results and experimental investigations, such as fatigue tests, frequently overlook the intricacies of the failure mechanism. Therefore, the elastic-plastic material behavior of DLC based coating systems with CrN support interlayer, deposited on 100Cr6 substrates and Si, was investigated. Using an inverse approach, a nanoindentation simulation with spherical indenter geometry was iteratively optimized to experimental curves by adjusting the material parameters Young's modulus E, yield strength Y, hardening coefficient K and hardening exponent n for DLC and CrN layers. Mechanical parameters were measured and the yield strength of DLC was analyzed with a scratch procedure to implement appropriate initial values. The results showed an overall good agreement between the measured and optimized force-displacement curves with reasonable determined material parameters. The control parameter Y exhibited nearly identical outcomes for scratch measurements and the calculated value from simulations although DLC was deposited on different substrates. The employment of a spherical indenter tip mitigates the influence of the microstructure in the CrN layer through homogenization effects and a larger affected area of the plastic zone. Furthermore, enhancing the performance of the coating systems can be achieved by increasing the DLC or CrN interlayer thickness.

Regulating the structure and performance of amorphous carbon-based films by introducing different interlayers for applications in PEMFC bipolar plates

In this work, the effects of inserting an interlayer on the anti-corrosion performance of amorphous carbon (a-C) films in a simulated Proton Exchange Membrane Fuel Cell (PEMFC) environment have been systematically studied. Four a-C films with different interlayers, namely CCr, C-Cr-N, CrN and Cr, were prepared on 316L stainless steel substrates using unbalanced magnetron sputtering. The surface/fractural morphologies, carbon bonding structure and the anti-corrosion performance of the 4 films were observed/characterized in detail. The nanostructure and composition evolution from the film surface down to the film-substrate interface before and after electrochemical tests were also analysed via high resolution transmission electron microscopy (HRTEM). Results indicate that a-C films with CCr and C-Cr-N interlayers display superior corrosion resistance compared to undoped samples and those lacking an interlayer, with the lowest self-corrosion current density (i.e. 2.1 × 10−7 A/cm2, C-Cr-N interlayer) being nearly two orders of magnitude lower than that of the substrate (i.e. 1.1 × 10−5 A/cm2). The doped C-Cr-N interlayer plays a vital role in the corrosion resistance of the samples by accelerating oxidation of surface defect locations, inhibiting the continuous penetration of electrolyte, and improving corrosion resistance. Additionally, a-C films with a C-Cr-N interlayer exhibited an outstanding interface contact resistance (ICR) value (~3.5 mΩ/cm2) than that with a CrN interlayer (~30 mΩ/cm2) or the 316L substrate (~100 mΩ/cm2) at a typical contact pressure of 1.5 MPa. All 4 films demonstrate obviously improved hydrophobicity (contact angles against distilled water under room temperature up to 94.2°) compared to the substrate (75.8° under identical condition). In a word, this study proves that the strategy of inserting an appropriately designed interlayer (with the ternary C-Cr-N being most promising) to a-C films could alter and enhance the anti-corrosion, ICR and hydrophobic properties of 316L, proposing valuable solutions for high-performance bipolar plates (BPs) in the PEMFC industry.

Enhance the tribological performance of soft AISI 1045 steel through a CrN/W-DLC/DLC multilayer coating

Special equipment vehicles typically operate in complex environments, leading to wear and failure of the chassis's rotary seal shaft predominantly made of soft AISI 1045 steel. An effective approach to prolong the service life is to apply a hard coating on the working surface. Previous research have primarily concentrated on the coating for hard high-speed steel. However, the significant disparity in physical characteristics between soft AISI 1045 steel and the hard coating results in a weak interface adhesion. This study produces a CrN/W-DLC/DLC multilayer coating on the soft AISI 1045 steel with strong interfacial adhesion and superior friction and wear property through modulation of the CrN transition layer thickness. The multilayer coating consists of five layers, a CrN transition layer, a Cr layer, a Cr/WC alternating layer, a W-DLC/DLC alternating layer, and the topmost DLC layer. The thickest CrN interlayer coating achieves the Lc2 and Lc3 value of 13.9 ± 0.2 N and 20.4 ± 0.9 N. The optimized CrN/W-DLC/DLC coating reduces the internal stress of the DLC coating and enhances its adhesion. Importantly, the average friction coefficient and wear cross-sectional area of the CrN/W-DLC/DLC multilayer coatings decrease accordingly. The thickest CrN interlayer coating exhibits superior outstanding wear resistance evidenced by an average friction coefficient of 0.119, a steady-state friction coefficient of 0.097 and a wear volume of 1.508 × 106 μm3. The presence of a high proportion of sp2 bonds in the thickest CrN interlayer coating, which are susceptible to graphitization, along with a thicker transition layer that enhances the coating's support, leads to narrower wear traces. The primary wear mechanisms observed in the friction and wear test of CrN/W-DLC/DLC coatings are oxidative wear and tribo-abrasive wear. The work provides a significant promise for application in vehicle rotary seal components and a theoretical reference for enhancing the wear resistance of the seal surface.

Wear performance under dry and lubricated conditions of duplex treatment TiN/TiCrN coatings deposited with different numbers of CrN interlayers on steel substrates

Cold work steels are used in harsh conditions including high load, wear, corrosion, and mechanical stresses that can easily lead to degradation and wear of the material. Generally, multilayer ceramics coatings are attractive candidates to develop engineering components by combining positive characteristics of different coatings. In this study, the TiN/TiCrN coatings with the different number of CrN interlayers were successfully deposited on nitrided and non-nitrided DIN 1.2379 steel, and their wear behavior was investigated at dry and lubrication conditions under different loads. The relationship between coating architectures and coating characteristics was explored. The microstructure and composition of the specimens were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) with Energy dispersive X-ray analysis (EDX) and Atomic force microscopy (AFM).The nano-hardness were measured by nanoindenter, respectively. The adhesion and tribological behavior were evaluated using the Rockwell-C indentation and reciprocating tribometer tests, respectively. The results reveal that the nitrided samples with the TiN/TiCrN coatings with the different number of CrN interlayer showed much better wear resistance than the non-nitrided coatings at dry conditions. On the other hand, nitrided and nitride + coated TiN/TiCrN with the different number of CrN interlayer specimen showed better wear resistance at lubricated conditions. In addition, the fact that uncoated and nitrided steels have higher wear resistance at lubricated conditions than coated samples shows that TiN/TiCrN coatings are not proper even with a lubricant additive over a certain load value.

Influence of Interlayer Materials on the Mechanical Properties and Thermal Stability of a CrAlN Coating on a Tungsten Carbide Substrate

CrAlN coatings have earned significant attention for use in cutting tool coating applications due to their excellent properties such as high hardness and superb oxidation resistance. It is well known that the interlayer between the coating and the substrate can influence the mechanical properties of the coatings. In this work, three interlayers—CrN, CrZrN, and CrN/CrZrSiN—were synthesized between a CrAlN coating and a tungsten carbide substrate to improve the mechanical properties and thermal stability of the CrAlN coating. All the CrAlN coatings with their respective interlayers showed high hardness values in the range of 34.5 to 35.1 GPa, and they were not significantly affected by the interlayer type. However, wear and scratch tests showed that the CrAlN coatings with CrN and CrN/CrZrSiN interlayers exhibited an improved friction coefficient of 0.33 and adhesion strength (Lc2) of 69 N compared to the CrAlN coating with the CrZrN interlayer. These improved wear properties were attributed to the H/E ratio of the interlayer between the coating and the substrate, in that the CrN and CrZrSiN interlayers effectively induced a smooth transition of the coating stress under a loading condition. During the thermal stability tests, the hardness of the CrAlN coating with the CrN/CrZrSiN interlayer was maintained up to 1000 °C due to the excellent oxidation resistance of the CrZrSiN layer, which contained an amorphous SixNy phase.

Tailoring the dissolution rate and in vitro cell response of silicon nitride coatings through combinatorial sputtering with chromium and niobium.

Ceramic coatings have been widely investigated as a means to reduce wear and metallic ion release from joint implants. Silicon nitride-based coatings have been a topic of interest specifically due to their solubility in aqueous solutions. This could imply a reduced adverse immune response since the generated debris would dissolve. However, there are concerns regarding the dissolution rate and adhesion of these silicon nitride-based coatings. This study attempts to address the concern of dissolution rate as well as coating adhesion of silicon nitride coatings. We hypothesized that alloying with chromium and niobium would affect the adhesion, dissolution rate, and the resulting ion release and cell response to the coatings. A combinatorial approach was used to deposit sputtered coatings with compositional gradients both with and without a CrN interlayer. Compositional gradients were achieved for all the investigated elements: Si (38.6-46.9 at%), Nb (2.2-4.6 at%) and Cr (1.9-6.0 at%). However, while the presence of an interlayer reduced the delamination during adhesion testing, the differences in composition in the top coating did not affect the adhesion. Nor did the top coating's composition affect the surface roughness or the coatings' inherent mechanical properties (elastic modulus and hardness). All coating compositions were associated with a low Co release from the underlying metal and points with a higher Cr content (4.3-6.0 at%) gave an overall lower release of Si, Cr and Nb ions, possibly due to the formation of a stable oxide, which reduced the dissolution rate of the coating. Optimum chromium contents were furthermore found to give an enhanced in vitro fibroblast cell viability. In conclusion, the results indicate a possibility to tailor the ion release rate, which lends promise to further investigations such as tribocorrosive tests towards a future biomedical application.

TEM Structure, Nanomechanical Property, and Adhesive Force of Magnetron-Sputtered Cr-DLC Coating on a Nitrided Ti6Al4V Alloy

A magnetron-sputtered Cr-diamond-like carbon (DLC) coating was deposited on nitrided Ti6Al4V alloys (TAs) by employing the CrN interlayer. The physical and chemical characteristics of the obtained coating were systematically studied using scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, high-resolution transmission electron microscopy, atomic force microscopy, X-ray diffraction, nanoindentation, and scratch tests. The results show that the Cr-DLC coating is an amorphous structure of carbon (C), and the Cr clusters are dispersed in the Cr-DLC coating. Raman analysis also confirms the existence of G and D peaks in the Cr-DLC coating. The Cr-DLC coating presents outstanding nanomechanical properties, and its nanohardness and elastic modulus are 19.29 and 168.8 GPa, respectively, which are contributed to the formation of diamond. The adhesive force of the Cr-DLC coating with the nitrided TA is determined to be 20.70 N by the scratch test, which is improved by the Cr–C bond of the CrN interlayer at a binding energy of 283.4 eV.

Electrochemical performance and corrosion mechanism of Cr–DLC coating on nitrided Ti6Al4V alloy by magnetron sputtering

A Cr–DLC coating was deposited on nitrided Ti6Al4V alloy (TA) by magnetron sputtering (MS) using CrN as an interlayer. The characterization processes of obtained coating were performed on scanning electron microscopy (SEM), energy dispersive spectroscope (EDS), X-ray diffraction (XRD), Raman spectroscopy and transmission electron microscopy (TEM), and the hardness and bonding strength were also measured by nanoindentation and scratch testers. The electrochemical corrosion performances of TA, nitrided TA and Cr–DLC coating in 3.5% NaCl solution were systematically investigated using an electrochemical workstation, and the corrosion mechanisms were discussed in detail. The results show that the amorphous carbon atoms are uniformly distributed on the in–situ grown Cr–DLC coating, and the CrN interlayer plays an important connection role between the Cr–DLC coating and the nitrided TA. After the electrochemical corrosion test, the O mass fraction on the Cr–DLC coating is lower than those on the TA and nitrided TA, and the nitrided TA is effectively protected from electrochemical corrosion. The Cr–DLC coating presents the smallest corrosion current density icorr and the largest polarization resistance Rp among the TA, nitrided TA and Cr–DLC coating, showing the outstanding electrochemical corrosion resistance. Meanwhile, the capacitive arc radius, impedance |Z| and phase angle of Cr–DLC coating are also the maximum, exhibiting that its electrochemical corrosion resistance is higher than the TA and nitrided TA.

Effects of ceramic-based CrN, TiN, and AlCrN interlayers on wear and friction behaviors of AlTiSiN+TiSiN PVD coatings

In this study, the wear and friction behavior of cathodic arc physical vapor deposited AlTiSiN+TiSiN coatings on H13 tool steels were investigated by using CrN, TiN and AlCrN interlayers with tribometer tests both under unlubricated and boundary lubricated conditions. 6 mm alumina balls were used as counter surfaces to test ceramic hard coatings. Surface coatings were characterized through nanoindentation, scanning electron microscopy coupled with an energy-dispersive X-ray spectrometer (SEM/EDXS), optical profilometry, and atomic force microscopy (AFM) techniques. The results showed that especially AlTiSiN+TiSiN coating with TiN interlayer resulted in a much more enhanced tribological performance of the tool steels at both unlubricated and the boundary lubricated conditions even at elevated contact pressures.

Selected Physicochemical Properties of Diamond Like Carbon (DLC) Coating on Ti-13Nb-13Zr Alloy Used for Blood Contacting Implants.

Despite high interest in the issues of hemocompatibility of titanium implants, particularly those made of the Ti-13Nb-13Zr alloy, the applied methods of surface modification still do not always guarantee the physicochemical properties required for their safe operation. The factors that reduce the efficiency of the application of titanium alloys in the treatment of conditions of the cardiovascular system include blood coagulation and fibrous proliferation within the vessel’s internal walls. They result from their surfaces’ physicochemical properties not being fully adapted to the specifics of the circulatory system. Until now, the generation and development mechanics of these adverse processes are not fully known. Thus, the fundamental problem in this work is to determine the correlation between the physicochemical properties of the diamond like carbon (DLC) coating (shaped by the technological conditions of the process) applied onto the Ti-13Nb-13Zr alloy designed for contact with blood and its hemocompatibility. In the paper, microscopic metallographic, surface roughness, wettability, free surface energy, hardness, coating adhesion to the substrate, impendence, and potentiodynamic studies in artificial plasma were carried out. The surface layer with the DLC coating ensures the required surface roughness and hydrophobic character and sufficient pitting corrosion resistance in artificial plasma. On the other hand, the proposed CrN interlayer results in better adhesion of the coating to the Ti-13Nb-13Zr alloy. This type of coating is an alternative to the modification of titanium alloy surfaces using various elements to improve the blood environment’s hemocompatibility.

Effect of the specific surface topography on surface wettability of chromium-based coatings

ABSTRACTSurfaces featuring hydrophobic behaviour are generally prepared by a wide spectrum of technologies featuring different process complexity (anodic oxidation, lithography, electrodepositing, etc.). The aim of the work was to use a relatively simple method of magnetron sputtering to prepare metallic hydrophobic surface. Chromium coatings were selected due to their high adhesion to steel and corrosion resistance while conserving certain level of hardness and ductility. The tested coatings included pure Cr and pure Cr with CrN interlayer. The resulting contact angle value of up to 111° has confirmed hydrophobic behaviour. The resulting surface morphology is formed by almost perfectly developed crystals in the shape of hexagonal pyramids providing a suitable surface roughness conditions for hydrophobicity.

Towards Functional Silicon Nitride Coatings for Joint Replacements

Silicon nitride (SiNx) coatings are currently under investigation as bearing surfaces for joint implants, due to their low wear rate and the good biocompatibility of both coatings and their potential wear debris. The aim of this study was to move further towards functional SiNx coatings by evaluating coatings deposited onto CoCrMo surfaces with a CrN interlayer, using different bias voltages and substrate rotations. Reactive direct current magnetron sputtering was used to coat CoCrMo discs with a CrN interlayer, followed by a SiNx top layer, which was deposited by reactive high-power impulse magnetron sputtering. The interlayer was deposited using negative bias voltages ranging between 100 and 900 V, and 1-fold or 3-fold substrate rotation. Scanning electron microscopy showed a dependence of coating morphology on substrate rotation. The N/Si ratio ranged from 1.10 to 1.25, as evaluated by X-ray photoelectron spectroscopy. Vertical scanning interferometry revealed that the coated, unpolished samples had a low average surface roughness between 16 and 33 nm. Rockwell indentations showed improved coating adhesion when a low bias voltage of 100 V was used to deposit the CrN interlayer. Wear tests performed in a reciprocating manner against Si3N4 balls showed specific wear rates lower than, or similar to that of CoCrMo. The study suggests that low negative bias voltages may contribute to a better performance of SiNx coatings in terms of adhesion. The low wear rates found in the current study support further development of silicon nitride-based coatings towards clinical application.

CVD deposition of nanocrystalline diamond coatings on implant alloy materials with CrN/Al interlayer

Integration of smooth nanocrystalline diamond coatings on biomedical implant substrates (CoCr, SS316) for enhanced biomedical performances has great application potentials due to their extraordinary wear/corrosion resistance and biocompatibility. However, chemical vapor deposition (CVD) of adherent diamond coatings on such substrates encounters a major technical barrier of weak interface bonding strength. In this study, single CrN interlayer of different thickness and duplex CrN/Al interlayer have been prepared on CoCr alloy and SS316 steel substrates to improve the adhesion of diamond coatings. The diamond coating produced with a single CrN interlayer up to 1 μm thick still shows insufficient adhesion ability to the substrates. A combination of CrN and Al, with a total thickness of 0.45 μm, significantly enhances the diamond coating/substrate bonding strength. The fundamental mechanism of enhanced interfacial adhesion is discussed in terms of the individual role the two kinds of interlayer materials play.

Tailoring of the interface morphology of WS2/CrN bilayered thin film for enhanced tribological property

The WS2/CrN bilayered films with different interface morphologies between WS2 and CrN layer were prepared by physical vapor deposition. By controlling the deposition parameters, the surface of CrN interlayer exhibited compact granular structure when deposited under low partial pressure of Ar while a cone array-like surface appeared under high Ar partial pressure. The surface texture of the CrN interlayer had a great effect on the tribological performance of the WS2/CrN film. The compact CrN textured WS2 film exhibited a wear life about 2.6 × 105 cycles while the optimal cone array-like CrN textured WS2 film showed a much longer wear life reaching to 6.8 × 105 cycles, which was more than 2.6 times of that for compact CrN textured WS2 film and 3.5 times of that for WS2 film without the CrN interlayer. The improved tribological property of the optimal cone array-like CrN textured WS2 film was attributed to the high adhesion between the WS2 layer and the CrN interlayer. Meanwhile, the reservoir and replenishment of the WS2 lubricant by the CrN nanocones during the friction made a significant contribution for the long wear life.

Raman Spectroscopy for Reliability Assessment of Multilayered AlCrN Coating in Tribo-Corrosive Conditions

In this study, a multilayered AlCrN coating has been employed as a protective layer for steel used in tribo-corrosive conditions. The coating was deposited by a lateral rotating cathode arc PVD technology on a AISI 316L stainless steel substrate. A ratio of Al/(Al + Cr) was varied from 0.5 up to 0.6 in the AlCrN layer located above Cr adhesion and gradient CrN interlayers. A Raman spectroscopy and potentiodynamic polarization scan were used to determine the resistance in tribo-corrosive (3.5 wt % NaCl) conditions. Correlation between sliding contact surface chemistry and measured tribological properties of material was supported with static corrosion experiments. The corrosion mechanisms responsible for surface degradation are reported.

Influence of the surface microstructure on the adhesion of a CVD-diamond coating on steel with a CrN interlayer

forming tool coating. Most of the forming tools are made of steel, so that especially the coatability of steel by a polycrystalline diamond coating would rise the range of fields of application. The polycrystalline CVD-diamond coatings are deposited by a laser induced plasma CVD process, without a vacuum chamber. Various surface microstructures were investigated regarding their influence on the residual stresses to prevent a flaking of the coating: on the one hand, deterministic structures generated by ultrasonic vibration assisted milling (UVAM) and on the other hand, stochastic structures manufactured by blasting and polishing processes. For the UVAM, a surface prediction tool was used to design the surface microstructure beforehand. All steel substrates (material no. 1.2379) were coated in one batch by high-power impulse magnetron sputtering with a chromium nitride coating with a thickness of 2.4 μm. The specimens were analysed by laser microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and Raman spectroscopy. None of the microstructures investigated in this study was able to prevent delamination of the coating entirely. It could be shown that a roughness higher than Sa 0.1μm supports the interlocking between coating and surface as well as that sharp peaks inhibit a homogenous diamond coating deposition.

Effect of interlayer design on friction and wear behaviors of CrAlSiN coating under high load in seawater.

In this paper, CrAlSiN coatings with different interlayer designs (without interlayer, Cr interlayer, CrN interlayer and Cr/CrN interlayer) were successfully obtained on 316L stainless steel and single crystal silicon by multi-arc ion plating technique. Coating microstructure, mechanical, anticorrosion and tribological behaviors in artificial seawater were systematically investigated by XRD, SEM, XPS, TEM, nanoindentation, electrochemical workstation and frictional tester system. Results showed that the CrAlSiN layer presented a typical nanocrystalline/amorphous structure, which consisted of CrN, AlN and Si3N4 phases. The Cr/CrN interlayer could obviously improve the adhesion, hardness and toughness of CrAlSiN coating. Compared with single CrAlSiN coating, the corrosion current density of Cr/CrN/CrAlSiN coating system was improved by 2 orders of magnitude and its inhibition efficiency was up to 98.82%. Under high applied load (15 N) condition, the CrAlSiN coating with Cr/CrN interlayer revealed the lowest COF (0.107 ± 0.009) and wear rate (7.3 × 10−8 ± 8.4 × 10−9 mm3 N−1 m−1) in seawater, which primarily attributed to the synergistic effect of ideal adhesion force, outstanding toughness and effectively barrier ability.

INFLUENCE OF PRETREATMENT ON DIAMOND-COATED TOOL NUCLEATION AND MACHINING PERFORMANCE

The CVD diamond film with favorable adhesion and relatively thinner thickness is essential facing for its application on drills for machining carbon fiber reinforced plastics (CFRP), with regard to either the tool lifetime or the machining quality. A 500-nm-thick CrN layer was deposited by the cathode arc technique on slight chemical etched WC–Co 6[Formula: see text]wt.% drill, and nano-crystalline diamond (NCD) is subsequently deposited by the hot filament chemical vapor deposition (HFCVD) technique. The same NCD film is also deposited on the drills pretreated only by the slight chemical etching or the CrN interlayer, which are adopted as comparisons in the present study. The nucleation and growth of diamond film and the cutting performance of the coated drills are systematically studied. The results show that the drill pretreated by the slight chemical etching and CrN interlayer can acquire highest nucleation density (ND) compared to the other pretreatment methods as it sufficiently prevents the Co diffusion. The diamond-coated drill with deep chemical etching was used for comparison to study the machining quality when drilling CFRP. During machining the CFRP, the failure mode of the diamond-coated drill is mainly the delamination and peeling off of the diamond film at areas with stress concentration, while the diamond-coated drill pretreated by slight chemical etching [Formula: see text] CrN interlayer can retard such failure. The exit hole quality of CRFP machined by drill pretreated with slight chemical etching [Formula: see text] CrN interlayer is better than that by drill pretreated with deep chemical etching, which is ascribed to the different cutting edges of the drills.

Bottom-up diamond nanorod growth in HFCVD from nanocrystalline diamond film as a template-free method

Nanocrystalline diamond (NCD) films are being used in a large number of applications. Also, diamond nanorods (DNRs) exhibit distinctive features that are not present in diamond films, because of the tunable large surface-to-volume ratio and tubular configuration. In this work, we report on the synthesis of DNRs by means of the bottom-up and template-free method from NCD films by the hot filament chemical vapor deposition system. The substrate materials used for diamond deposition were stainless steel (AISI 316) and chromium nitride-coated stainless steel. On both substrates, NCD films and then DNRs have been synthesized. The micro-Raman confirms that the synthesized structure is NCD. In addition, the grazing incident x-ray diffraction pattern confirms the presence of cubic diamond and rhombohedral diamond as a film on the CrN and Cr2N interlayer. Also, the DNRs are encased in an amorphous carbon (a-C) shell. The DNRs are grown on the NCD grains by a bottom-up technology and template-free method. Their orientations are almost random in the diamond thin-film surface. In addition, the density of DNRs on the NCD film for the CrN interlayer is more than for the stainless-steel substrate. The NCD/DNR films are dense, adhesive, continuous, and almost uniform on the CrN-coated stainless-steel substrate.

Wear performance of diamond coated WC-Co tools with a CrN interlayer

In this paper we report the wear performance of diamond coated WC-Co cutting tools with a CrN interlayer by machining Al-Si alloys. Diamond films were deposited on both WC-6%Co (Arno) and WC-10%Co (Sandvik) substrates with a CrN interlayer using the hot filament chemical vapor deposition technique. Adhesion assessment by the indentation technique shows that there was no major delamination of diamond coatings on any substrate at a load of 196N. The stress field image of the region close to the indentation marks using Raman spectral imaging shows the splitting of the first order Raman line as well as a shift in the peak position to a higher frequency. Machining experiments of diamond/CrN/WC-6%Co tools with the Al-Si alloy (AlSi17Cu4Mg) workpiece shows a wear performance of VBmax=0.1mm at tc=960s, however, their performance in impact tests was not as high. On the other hand, machining experiments of diamond/CrN/WC-10%Co tools with an Al-Si alloy workpiece showed an excellent wear performance (VBmax=0.17mm at tc=960s), alongside an improved coating-substrate interface fatigue strength. A combined study using indentation, turning and impact tests demonstrates the potential advantage of diamond coatings on WC-10%Co substrates with a CrN interlayer for machining of Al-Si alloys and other high impact applications.