CrAlN Coatings Research Articles

SIMS depth profile analysis of tribological coatings on curved surfaces: Influence of ion impact angle and take‐off angle on ion yield and on the quantitative analysis of chemical composition

Quantitative analysis of chemical composition of materials by SIMS depth profiling is challenging due to strong matrix effects. However, by using the MCs+‐cluster method in conjunction with matched standards, a quite good quantification is possible. Another source of errors can be nonflat (curved) surfaces, which is often the case in coated parts of automotive or tool industry (injection needles, plungers, pistons, and drills). In such cases, the impact angle of the ion beam or the take‐off angle of the mass spectrometer can locally differ from that of a flat sample. This has influence on the ion count rates and therefore on the quantification. In this paper, we use the MCs+ method to analyze DLC, W‐DLC, CrN, TiN, TiAlN, and CrAlN coatings with respect to the influence of a tilt of the sample surface to the secondary ion yield and on the quantification of coating stoichiometry. Impact angle and take‐off angle have been varied in a wide range. It was found that ion intensities for nitridic systems vary by up to a factor of 30 when changing the impact angle of the ion beam, while for carbon‐based systems the maximum variation is only a factor of 2. Take‐off angle variations may change ion count rates by a factor of 5 up to 50. As a consequence, a tilt depending error in quantification of chemical composition of coatings may occur, which typically can be in the range of 5% to 20%, while it can increase up to 40% in some cases.

Wear performance of Y-doped nanolayered CrN/AlN coatings

The incorporation of yttrium (Y) in CrAlN based hard coatings has been known to be able to improve the oxidation resistance and thermal stability of these coatings, which is an important characteristic for protective coatings at high temperatures. However, there has been limited information available for the effects of Y doping on the tribological properties of such coatings, especially the wear performance. In this paper, a systematic investigation on the triblogical properties of CrAlN coatings doped with different levels of Y was conducted to correlate the coatings' microstructural, mechanical and tribological properties with their Y contents. The results showed that the wear performance of the coatings decreased with increasing Y doping, though the coatings doped with low to moderate Y contents had comparable wear performance with the pristine CrAlN coatings.

Structure, Morphology, and Mechanical Properties of AlCrN Coatings Deposited by Cathodic Arc Evaporation

AlCrN coatings were deposited on steel substrates (HS6-5-2) using cathodic arc evaporation. The effect of nitrogen pressure on the properties of CrAlN coatings formed from Al80Cr20 cathode, such as chemical and phase composition of the coatings, surface morphology, deposition rate, hardness and adhesion to the substrate, and friction and wear were investigated. The coating deposited at nitrogen pressure of 3 Pa shows the highest deposition rate. The roughness parameter Ra of the coating surface decreases with increasing nitrogen pressure during its formation. The test results showed that the AlCrN coatings deposited under nitrogen pressure in the range from 1 to 5 Pa show similar hardness for all the coatings, which is around 17 GPa. The increase in the negative bias voltage of the substrate during the formation of the coating deteriorates its adhesion to the substrate, although the wear rate is rather good, about 1.4 × 10−7 mm3/Nm. The coatings deposited at nitrogen pressure of 3-4 Pa are characterized by the highest critical load, 95 N. Despite worse adhesion, these coatings are characterized by high resistance to wear, the wear rate is about 1.4 × 10−7 mm3/Nm.

Erosion Wear Behavior of CrAlN Coating Produced by Pulsed Filtered Vacuum Cathode Arc Deposition Assisted with Plasma

To improve the tribological properties, it is important to reduce the growth defects in PVD hard coatings. CrAlN coating was deposited on the substrate of a hard metal by pulsed filtered vacuum cathode arc deposition assisted with plasma (PFVCADP). The surface morphology of the original coating was examined by scanning electron microscope (SEM). SEM images of the coating surfaces showed that the surface growth defects in the CrAlN coating were reduced markedly. The coating was eroded by solid angular SiC particles. The analysis of the morphologies of the surface and cross section of the eroded coatings proved that the coating material was removed by brittle fatigue fracture of the coating material. The erosion wear of the coating behaved as brittle materials. The fragments were so fine that the eroded surface became smoother with the increase of the impacts from the particles and the particles impingements played a role of polishing to the coating surface.

Structure, morphology and mechanical properties of AlCrN coatings obtained by the method of cathodic arc evaporation

CrAlN coatings have been formed on steel substrates (HS6-5-2) using cathodic arc evaporation. The influence of nitrogen pres-sure and substrate bias voltage on the properties of CrAlN coatings formed from Al80Cr20 cathode, such as: chemical and phase composition of the coatings, their surface morphology, deposition rate, hardness and adhesion to the substrate have been investigated. It has been determined that the rate of the deposition of coatings in the nitrogen atmosphere with the pressure of 3 Pa is the highest and that with the increase of the negative bias voltage of the substrate the deposition rate decreases. The roughness parameter Ra of the coating surface decreases as the nitrogen pressure increases during their formation. Presumably, this is related to the reduction of the amount of macroparticles on the surface of the coating. The hardness of the coatings (taking into account the measurement uncertainty) is independent of the nitrogen pressure, but it increases with the increase of the negative bias voltage of the substrate. The adhesion of the coating increases with the increase of the nitrogen pressure to 3–4 Pa, and then it decreases. The increase in the negative bias voltage of the substrate during the formation of the coating deteriorates its adhesion to the substrate.

Oxidation Behavior of Cr<sub>1-x</sub>Al<sub>x</sub>N Coatings Deposited by Closed Field Unbalanced Magnetron Sputtering at 800°C

CrN coating possesses high strength, hardness and good resistance to friction. In order to further improve the performance of CrN coating, especially the high temperature resistance, a series of Cr1-xAlxN coatings with different Al content were deposited on the surface of 316 stainless steel by closed field unbalanced magnetron sputtering (CFUBMS). The microstructure, mechanical properties of Cr1-xAlxN coatings were investigated by XRD, FESEM/EDS and microhardness tester, respectively. The oxidation behaviors of Cr1-xAlxN coatings at 800°C were also studied. The results showed that with the increase of Al content, the hardness of the coating increases first and then decreases, and the binding force decreases gradually, and its microstructure is gradually refined. The phases in CrAlN coatings are mainly CrN and AlN. As the amount of Al increases, the number of dense oxide films on the surface of the coating increases, increasing the antioxidant capacity of the coating.

Structural, mechanical and thermal properties of CrAlNbN coatings

Alloying is an efficient way to improve or tailor the properties of CrAlN coatings, which have been extensively used as wear protective layers onto cutting and forming tools. Here, we have investigated the influence of Nb on the mechanical properties, thermal stability and oxidation resistance of CrAlN coatings. Cr0.48Al0.52N, Cr0.38Al0.57Nb0.05N, and Cr0.35Al0.55Nb0.10N coatings, deposited by cathodic arc evaporation, reveal a single-phase face-centered cubic structure with a hardness of 30.8 ± 0.9, 32.3 ± 0.8 and 32.3 ± 1.0 GPa, respectively. The addition of Nb improves the thermal stability of CrAlN via postponing the dissociation of CrN bonds from 1100 °C for CrAlN to 1200 °C for CrAlNbN, which endows Nb-containing coatings with the higher hardness upon annealed at elevated temperatures. Nevertheless, alloying with Nb decreases the proportion of protective (Cr, Al)2O3 layer and promotes the early formation of CrNbO4 and thus weakens the oxidation resistance of CrAlN coating. After oxidation at 1000 °C with a duration of 10 h, the Cr0.38Al0.57Nb0.05N and Cr0.35Al0.55Nb0.10N coatings exhibit a thicker oxide scale of ~0.7 and ~0.8 μm with Cr-rich/(Al, Nb)-rich bilayered structure, while the Cr0.48Al0.52N still have a dense oxide layer with a thickness of ~0.2 μm.

Effect of V-addition on the thermal stability and oxidation resistance of CrAlN coatings

Since the superiority of tribological properties, V-containing coatings, with the potential to generate lubricious Magnéli oxides at elevated temperatures, are regarded as excellent candidates for machining applications. Here, a study was conducted to shed light on the intrinsic thermal stability, mechanical properties and oxidation resistance of V-alloyed CrAlN coatings deposited by cathode arc evaporation. The hardness of Cr0.48Al0.52N and Cr0.44Al0.50V0.06N coatings with a single-phase face-centered cubic structure is 30.8 ± 0.9 and 33.0 ± 1.3GPa, respectively. Upon annealing in Ar atmosphere, Cr0.44Al0.50V0.06N coating reveals a retarded precipitation of wurtzite AlN as well as a postponement in Cr–N disintegration as compared to V-free Cr0.48Al0.52N coating, owing to the solid solution of V with a stronger binding capacity with nitrogen. The improved structural stability of Cr0.44Al0.50V0.06N coating contributes to the mild decline in hardness and elastic modulus upon annealing. When exposed to air, the incorporation of V into CrAlN promotes the formation of (Al, Cr)2O3 mixed oxide as well as additional V2O5, leading to a significantly lower onset temperature for oxidation. The existence of V2O5 degrades the protective of (Al, Cr)2O3 oxide layer and causes a complete oxidation of Cr0.44Al0.50V0.06N coating at 950°C, where only a dense and thin oxide scale can be detected in Cr0.48Al0.52N coating.

Residual stress control in CrAlN coatings deposited on Ti alloys

In order to control residual stress of CrAlN coatings on Ti substrates, ~70nm CrAl interlayer was deposited at different temperatures. Residual stress and coatings’ structure were characterized by X-ray diffraction. Residual stress in the coatings was compressive and increased with CrAl interlayer deposition temperature. Residual stress in 1.5µm, 2µm and 2.6µm thick CrAlN films on TC21 with the interlayer deposited at 100°C (−47.43MPa, −25.57MPa and −855.77MPa, respectively) was smaller than with the interlayer deposited at 300°C (−1.39GPa, −1.95GPa and −1.62GPa, respectively). The coatings on the TC4 substrate showed the same trend (−1.02GPa, −389.91MPa and −1.03GPa for the interlayer deposited at 100°C, respectively, and −921.42MPa, −2.31GPa and −1.80GPa for the interlayer deposited at 100°C, respectively). Changing the interlayer deposition temperature can influence the coatings’ residual stress and crystal structure, and improve mechanical properties of the coatings. CrAlN deposition is a convenient and efficient way to improve mechanical properties of Ti alloys.

A Comparative Study of TiAlN and CrAlN Coatings Deposited on Sialon Ceramic Cutting Inserts by Physical Vapor Deposition

TiAlN and CrAlN coatings were prepared by physical vapor deposition (PVD) on Sialon ceramic cutting tools. The results illustrated that the surface morphology of TiAlN coating was smoother than that of CrAlN coating. The thickness of TiAlN coating was about 1 μm, which was thicker than that of CrAlN coating (about 0.5μm). However, the hardness of TiAlN coating was lower (30.1 GPa) than that of CrAlN coating (37.5 GPa). Also the elastic modulus of TiAlN coating (346.9 GPa) was also lower than that of CrAlN coating (430.7 GPa), indicating that the stiffness of CrAlN coating was better than that of TiAlN coating. According to scratch tests, the adhesion force of TiAlN and CrAlN coatings were 31 N and 45 N, respectively, which revealed that the CrAlN coating exhibited better adhesion than the TiAlN coating. Cutting performance of the TiAlN coated and CrAlN coated Sialon ceramic cutting inserts were investigated by turning nickel-based alloys under dry conditions. For comparison, uncoated Sialon ceramic cutting inserts were also used for turning tests under the same conditions. The results indicated that the cutting performance of the inserts was considerably improved by the TiAlN and CrAlN coatings on the surfaces. The dominant failure mechanisms of the CrAlN coated inserts were abrasive and adhesive wear, whereas adhesive wear and spalling were the main failure mechanisms of the TiAlN coated inserts. The service life of TiAlN and CrAlN coated inserts were much longer than that of the uncoated inserts, indicating that the two coatings could effectively protect the inserts from wear.

Structure, mechanical, and thermal properties of Ti1‐xAlxN/CrAlN (x = 0.48, 0.58, and 0.66) multilayered coatings

AbstractNano‐multilayered TiAlN/CrAlN coatings combining advantages of Ti‐Al‐N and Cr‐Al‐N are considered to be promising candidates for advanced machining processes. Here, the structure and thermal properties of Ti1‐xAlxN/CrAlN (x = 0.48, 0.58, and 0.66) multilayered coatings as well as referential Ti1‐xAlxN and Cr0.32Al0.68N monolithic coatings were investigated. Ti1‐xAlxN coatings show a structural transformation from cubic structure for x = 0.48 to mixed cubic and wurtzite structure for x = 0.58 and 0.66, and Cr0.32Al0.68N coating exhibits a single cubic structure. Through a multilayer arrangement with Cr0.32Al0.68N layers, the Ti0.52Al0.48N and Ti0.42Al0.58N layers can be stabilized in their metastable cubic structure, but the Ti0.34Al0.66N layer still tends to crystallize in the mixed cubic and wurtzite structure. The hardness of Ti0.52Al0.48N/CrAlN and Ti0.42Al0.58N/CrAlN coatings is higher than that of corresponding monolithic coatings regardless of as‐deposited and annealed states. Especially, after annealing at 800°C, the Ti0.52Al0.48N/CrAlN and Ti0.42Al0.58N/CrAlN coatings reach their peak hardness of ~34.2 and 32.8 GPa due to the spinodal decomposition of Ti1‐xAlxN layers. However, the oxidation resistance of Ti1‐xAlxN/CrAlN coatings is mainly up to the Al content of Ti1‐xAlxN layers, where only the Ti0.34Al0.66N/CrAlN coating can survive the 10 h exposure to air at 1000°C.

Influence of Al Content on the Microstructure and Properties of the CrAlN Coatings Deposited by Arc Ion Plating

Four CrAlN coatings with various Al content were prepared by arc ion plating technology under different target currents. The effect of the Al content on the microstructure, chemical compositions, element chemical bonding states and mechanical properties of the CrAlN coatings was analyzed. X-ray diffraction results show that the primary phase of the CrAlN coating is fcc-(Al, Cr)N when the Al content is about 44.02 at.%. However, when the Al content increases to about 53.34 at.%, hcp-AlN phase emerges in the coating. And the hcp-AlN phase becomes the main phase in the CrAlN coating with Al content of about 69.55 at.%. Cross-sectional images show that all the four coatings possess dense structures and the deposition rate of Al atom is higher than that of Cr atom. The hardness of the CrAlN coating with Al content about 44.02 at.% is the largest (3149.72 HV) due to the solid solution hardening effect of the Al element. When the hcp-AlN phase is generated in the CrAlN coating, the hardness declines. The tribological experiment shows that the wear resistance of the CrAlN coating decreases gradually with increasing Al content when sliding against 100Cr6 steel ball.

Theoretical and experimental study of the gradient properties and the resulting local crystalline structure and orientation in magnetron-sputtered CrAlN coatings with lateral composition and thickness gradient

Cr–Al–N coatings with a lateral composition gradient were deposited from two segmented Cr/Al targets with different segment size, thus covering the Al content range 0.22 ≲ c ≲ 0.87 and a thickness range from several hundred nanometres to several micrometres. The two-dimensional thickness and composition profiles were determined nondestructively from X-ray fluorescence maps. The results were reproduced by simulations of the flux distribution on the sample surface, combiningTRIDYNsimulations of the reactive sputter process at the target surface andSIMTRAsimulations of the subsequent transport through the gas phase. The phase formation was studied by spatially resolved X-ray diffraction and X-ray absorption spectroscopy at the Cr Kedge. Forc ≲ 0.69, a single-phase solid solution face-centered cubic (f.c.c.) (Cr,Al)N phase was found, and for 0.69 ≲ c ≲ 0.87 coexisting f.c.c. (Cr,Al)N and hexagonal close packed (h.c.p.) (Cr,Al)N phases were observed. The biaxial texture formation in nearly the entire composition range indicates a zone T growth. Four, mainly composition-dependent, texture regions were identified. All observed textures are closely related to textures reported for the h.c.p. AlN and f.c.c. CrN parent phases. Forc ≳ 0.69, a strong thickness dependence of the textures was observed. The measurements reveal an orientation relation between different f.c.c. and h.c.p. textures, indicating that local epitaxy might play a role in the structure formation.

PVD-CrAlN and TiAlN coated Si 3 N 4 ceramic cutting inserts-2. High speed face milling performance and wear mechanism study

Abstract In the authors’ prior works, the microstructure, turning cutting performance and wear mechanisms of PVD-CrAlN and TiAlN coated silicon nitride cutting inserts on turning of gray iron were studied. In the present work, based on the authors’ former study, the effects of the cutting speed on tool life, wear mechanism and surface quality of the workpieces were studied through high speed face milling tests. The uncoated, CrAlN and TiAlN coated cutting inserts were conducted by high speed face milling of gray iron at various cutting speeds of 600 m/min~1500 m/min. The results displayed that during high speed face milling, the tool life of the PVD coated Si 3 N 4 cutting inserts decreased as the cutting speed increased. When the cutting speed reached a certain value, the tool life increased with the cutting speed increasing. During high speed face milling, no spallation failure happened to both CrAlN and TiAlN coatings, and the coatings could protect the insert substrates effectively under various cutting speeds, improving the tool life of the uncoated cutting inserts by 138–150% and 32–65%, respectively. The wear mechanisms of all three kinds of the cutting inserts by face milling of gray iron under various cutting speed were the same. The only difference was that as the cutting speed increased, the adhesive wear of the inserts increased significantly. During high speed face milling of gray iron with three kinds of inserts, the alteration relationship of machining quality with the cutting speed was similar to the tool life with the cutting speed relationship. Furthermore, when high speed face milling of gray iron was conducted, CrAlN coated Si 3 N 4 cutting inserts displayed the best machining quality, followed by TiAlN coated and the uncoated inserts, respectively.

PVD-CrAlN and TiAlN coated Si 3 N 4 ceramic cutting tools —1. Microstructure, turning performance and wear mechanism

Abstract In this work, CrAlN and TiAlN coatings were produced on silicon nitride cutting inserts via physical vapor deposition. The microstructure and hardness of the coatings, as well as the adhesive strength between the coating and the substrate were studied using a scanning electronic microscope, a micro hardness tester and a scratch tester, respectively. Continuous turning tests of the obtained CrAlN and TiAlN-coated silicon nitride cutting inserts were performed on gray cast iron to evaluate the cutting performances and the machining quality. The results show that the surface hardness of the Si 3 N 4 cutting inserts could be improved by 87% and 50%, respectively, when applying the CrAlN and TiAlN coatings, thereby enhancing the abrasion resistance of the cutting inserts. At different tested cutting speeds, abrasive wear under compressional deformation and adhesive wear were identified as the main failure mechanisms for the two cutting inserts during continuous turning of gray cast iron. The machining quality of the gray cast iron workpieces machined using the uncoated, the CrAlN- or the TiAlN-coated inserts increased with the increment of the cutting speed.

Interfacial structure, mechanical properties and thermal stability of CrAlSiN/CrAlN multilayer coatings

Incorporation of Si into CrAlN coatings has a positive effect on the mechanical and thermal properties, but promotes the wurtzite (w) AlN formation with decreased mechanical properties. In order to further optimize the properties of CrAlSiN coatings, multilayer architecture combining with single phase cubic (c) CrAlN layers and mixed cubic/wurtzite layers, where the CrAlSiN/CrAlN (ML) multilayer coatings with a similar modulation period and varied modulation ratios were prepared, is used to stabilize CrAlSiN sublayers in their metastable cubic structure by coherency to the CrAlN sublayer. The ML_1 coating with coherent growth between 1.4nm CrAlSiN layer on the 2.9nm cubic CrAlN layer exhibits large columnar grains extending over several layers. The increased thickness of CrAlSiN layer induces the coherency loss, and reveals a mixed c/w-ML_2 and _3 multilayer coatings. The ML_1 coating obtains the maximum hardness value of ~33.1GPa due to the coherency strain and overall cubic formation, corresponding to ~31.2 and 31.6GPa for ML_2 and _3, respectively. However, ML_1 coating presents an earlier w-AlN precipitation and N-loss than CrAlN and CrAlSiN monolithic coatings under thermal load.

Corrosion Resistance Behavior of Single-Layer Cathodic Arc PVD Nitride-Base Coatings in 1M HCl and 3.5 pct NaCl Solutions

The electrochemical behavior of single-layer TiN, CrN, CrAlN, and TiAlN coatings on 304 stainless steel substrate, deposited using state-of-the-art and industrial size cathodic arc PVD machine, were evaluated in 1M HCl and 3.5 pct NaCl solutions. The corrosion behavior of the blank and coated substrates was analyzed by electrochemical impedance spectroscopy (EIS), linear polarization resistance, and potentiodynamic polarization. Bond-coat layers of pure-Ti, pure-Cr, alloyed-CrAl, and alloyed-TiAl for TiN, CrN, CrAlN, and TiAlN coatings were, respectively, first deposited for improved coating adhesion before the actual coating. The average coating thickness was about 1.80 µm. Results showed that the corrosion potentials (Ecorr) of the coated substrates were shifted to more noble values which indicated improvement of the coated substrate resistance to corrosion susceptibility. The corrosion current densities were lower for all coated substrates as compared to the blank substrate. Similarly, EIS parameters showed that these coatings possessed improved resistance to defects and pores in similar solution compared to the same nitride coatings developed by magnetron sputtering. The charge transfer resistance (Rct) can be ranked in the following order: TiAlN > CrN > TiN > CrAlN in both media except in NaCl solution where Rct of TiN is lowest. While the pore resistance (Rpo) followed the order: CrAlN > CrN > TiAlN > TiN in HCl solution and TiAlN > CrN > CrAlN > TiN in NaCl solution. It is found that TiAlN coating has the highest protective efficiencies of 79 and 99 pct in 1M HCl and 3.5 pct NaCl, respectively. SEM analysis of the corroded substrates in both media was also presented.

Effect of Laser Power on Delamination Initiation Behaviour of CrAlN Coating on Steel Substrate Laser-Quenched after Coating Process under Rolling Contact Fatigue

In order to investigate the effects of new surface modification method “Laser quenching after coating” on the rolling contact fatigue strength of ceramic coated steel, CrAlN coated specimens were processed by this method under various laser power conditions, and the thrust type rolling contact fatigue tests were carried out for these specimens. The delamination initiation life of CrAlN coated specimen increased with the laser power, however the excessive laser power decreased the delamination initiation life. The adhesive strength of CrAlN coated specimen showed similar variation for the increase of the laser power. The film hardness was almost constant for the increase of the laser power, however the excessive laser power also decreased the film hardness. From these results, it was considered that the increase of the delamination initiation life of CrAlN coated specimen was caused by the increase of the adhesive strength, and the decrease of the delamination initiation life at high laser power was affected by the decrease of the adhesive strength and/or the film hardness.

Influence of titanium or aluminum doping on the electrochemical properties of CrN coatings in artificial seawater

Abstract CrN, CrTiN and CrAlN coatings were deposited on Si (100) via co-sputtering chromium, titanium and aluminum targets by using unbalanced magnetron sputtering, respectively. And the relevant microstructure and composition were characterized. The influences of the doping elements on the microstructural and electrochemical properties of CrN coatings in the artificial seawater were analyzed via the open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests. As a result, the CrN coating exhibits the favorable corrosion resistance. On the contrary, the easy occurrence of hydration reaction for AlN would lower the compactness of CrAlN, subsequently deteriorate its corrosion resistance. Thus, the CrAlN coating presents the worst electrochemical properties in spite of its highest electrical resistivity. In particular, the CrTiN coating exhibits the outstanding corrosion resistance with relatively higher charge transfer resistance (R ct ), polarization resistance (R P ) due to its great compactness.

EFFECTS OF Mo CONTENT ON THE MICRO-STRUCTURE AND TRIBOLOGICAL PROPERTIES OF CrMoAlN FILMS

In recent decades, CrAlN coatings have been widely used for cutting tools due to their high hardness, good wear resistance, especially excellent thermal stability and oxidation resistance. However, the rapid development in high speeds and dry cutting applications demands further improvement in hardness and wear properties of CrAlN coatings. Mo nitrides coatings are commonly used as protective surface layers against wear and corrosion. The combination of CrAlN and Mo may lead to the development of new composite coatings with superior wear properties. In this study, the CrMoAlN multilayer coatings with different Mo contents were deposited on M2 tool steel and silicon wafers substrates by closedfield unbalanced magnetron sputtering ion plating (CFUMSIP) technique in a gas mixture of Ar+N2. The chemical composition, surface and cross sectional morphologies, microstructure, mechanical and tribological properties of coatings were studied by EDS, SEM, XRD, XPS, nano-indentation and pin-on-disk tribometer, respectively. The results indicate that the CrMoAlN coatings exhibit fcc structure. Mo atoms substitute Cr and/or Al atoms in CrAlN lattice forming the solid solution CrMoAlN coatings. The surface and cross-sectional morphologies of the CrMoAlN coatings show that the grain size and the column width decrease with the increasing of Mo content. Nano-indentation result reveals a promoted hardness and elastic modulus *浙江省自然科学基金资助项目Y15E050060 收到初稿日期: 2015-09-21,收到修改稿日期: 2016-03-09 作者简介:楼白杨,女, 1958年生,教授,博士 DOI: 10.11900/0412.1961.2015.00493 第727-733页 pp.727-733