Growth and characterization of Cr2N/CrN multilayer coatings

A series of monolithic and multilayer coatings of chromium nitride with various compositions and architectures were deposited at low temperatures (<200°C) on silicon substrates using ion-assisted reactive magnetron sputtering. All coatings had a total thickness in the 1.5±0.3 μm range. The multilayer coatings were designed such that their period and CrN fraction varied in the range 30–150 nm and 0.50–0.93, respectively. Real-time in situ ellipsometry was used to monitor and control the deposition process. The deposited coatings were characterized post-deposition using X-ray diffraction (XRD), Rutherford backscattering (RBS), X-ray photoelectron spectroscopy (XPS), and spectroscopic ellipsometry (SE). The primary chromium nitride phases (Cr₂N and CrN) in the films were identified using XRD. The chemical composition of selected samples was determined from RBS and XPS measurements. The phase composition of the deposited layers was deduced from the analysis of the SE data. The mechanical properties of the coatings were evaluated using a nanoindenter. The measured hardness values were in excess of 20 GPa. The results of the different characterization and testing techniques were correlated and follow-up work on this project suggested.     

Deposition of TiN thin films on Si(100) by HCD ion plating

Titanium nitride (TiN) films were deposited on Si(100) substrates using a hollow cathode discharge ion plating (HCD-IP) technique. Based on previous experimental results, the optimum deposition conditions were chosen. The thickness of the TiN film and the angle between the specimen surface and the evaporating source (coating angle) were selected as the variable parameters. The purpose of this study is to investigate the effect of these two processing parameters on the properties of TiN films. After deposition, the thin film structure was characterized by X-ray diffraction (XRD), cross-sectional transmission electron microscopy (XTEM), and field-emission-gun scanning electron microscopy (FEG-SEM). N/Ti ratios of the thin films were determined using both X-ray photoelectron spectrometer (XPS) and Rutherford backscattering spectrometer (RBS). The resistivity of the TiN films was measured by a four-point probe. The hardness of the thin films was obtained from nanoindentation tests. An atomic force microscope (AFM) was used to measure the roughness of the thin films. The results showed that (111) was the dominant preferred orientation in the TiN films for most of the deposition conditions and for all coating angles, especially for film thicknesses greater than 1 μm. Hardness values of TiN films were approximately 28 GPa for film thicknesses close to 0.5 μm and above, and did not vary with the coating angle. The hardness can be correlated to the (111) preferred orientation of the TiN film. The hardness increased with the (111) texture coefficient and leveled off as the texture coefficient approached 1. The packing factor had a linear relationship with the film thickness. Resistivity decreased with increasing thickness and increasing packing factor for all coating angles. At a similar thickness or packing factor, specimens coated at angles different from 0° had a much higher resistivity than those coated at 0°.     

多弧离子镀制备TiN/TiBN纳米复合涂层的结构和性能

为了满足复合材料高速切削加工的需要,用金属Ti靶和纯TiB2靶作为靶材料,在N2气氛下用多弧离子镀方法制备了TiN/TiBN纳米复合涂层。利用X射线衍射仪(XRD)、X射线光电子能谱仪(XPS)、扫描电子显微镜(SEM)和原子力显微镜(AFM)分析涂层的组织结构、成分和表面形貌;利用显微硬度计、划痕仪和球盘摩擦仪分析调制周期对涂层力学性能的影响。结果表明:TiN/TiBN纳米复合涂层的调制周期范围为5.5~21nm,主要成分为晶相TiN、非晶BN和TiB2;调制周期对涂层的力学性能有较大的影响,随着调制周期的减小,硬度增加,调制周期最小时最大硬度达到29GPa;最大膜基结合力为88N,且所有样品均表现出较高的膜基结合力。随着转速的增大,摩擦因数与表面粗糙度两者表现出相同的变化趋势,摩擦因数最大值为0.31,其低摩擦因数与自润滑的BN相的存在有关。调制周期减少,界面积增加,TiN/TiBN纳米复合涂层的力学性能增强。     

Structure-property-performance relations of high-rate reactive arc-evaporated Ti-B-N nanocomposite coatings

This study demonstrates the successful synthesis of hard and wear resistant nanocomposite Ti-B-N coatings by high-rate reactive arc-evaporation from Ti/B compound targets in a commercial industrial-sized deposition chamber. Morphological investigations by profilometry and scanning electron microscopy indicate that the coatings exhibit a lower droplet density as compared to a TiN reference as well as a compositionally graded multilayer structure. These results will be related to the previously reported microstructural characterization, which revealed a highly stressed nanocrystalline TiBN solid solution formed at lower N₂ fractions and a stable TiN/(amorphous) BN dual-phase structure obtained at higher N₂ partial pressures. Emphasis is further laid on mechanical and tribological characterization. A maximum hardness of 34.5 GPa is detected for the TiBN solid solution decreasing to 24 GPa for the coatings containing approximately 30-40 vol.% amorphous BN. The maximum in hardness coincides with the minimum in wear, while the coefficient of friction is fairly constant at 0.7-0.8.     

304不锈钢表面单层/多层TiN基涂层制备及耐磨蚀性能研究

目的探究钢基表面TiN基涂层在海洋环境中的耐磨蚀性能。方法采用电弧离子镀技术,在304不锈钢和单晶硅表面分别沉积TiN、TiBN、TiBN/TiN涂层,并对3种涂层样品的表面–截面形貌、摩擦系数、在人工海水中的电化学性能和摩擦腐蚀行为进行测试。结果形貌表征和干摩擦测试结果显示,TiBN和TiBN/TiN涂层有着比TiN柱状晶更加致密的微观结构,3种涂层的摩擦系数相差不大,比304SS的摩擦系数低。在人工海水环境中的电化学测试结果表明,TiBN/TiN涂层的耐腐蚀性能最佳,TiBN涂层次之,TiN涂层则表现出比304不锈钢基底更差的耐腐蚀特性。在发生摩擦腐蚀的过程中,3种涂层的电位（OCP）均发生了下降。结论利用电弧离子镀技术在304不锈钢表面沉积的单层/多层TiN基涂层,在人工海水环境下,发生的摩擦会增加涂层发生腐蚀的趋势,结构致密,表面易形成钝化膜的涂层,其耐磨蚀性较好。     

工作气压对TiBN/TiAlSiN纳米多层涂层的结构和性能影响

为应对高速干式切削、工磨具行业对新型防护涂层的需求,制造高硬度、耐摩擦磨损的纳米复合涂层具有巨大的市场前景。 采用阴极多弧离子镀技术,在不同的工作气压下用 TiB2 和 TiAlSi 合金靶作为阴极蒸发靶材,在硬质合金衬底上分别沉积了 TiBN,TiAlSiN 涂层和 TiBN/ TiAlSiN 多层涂层。 借助于 XRD、 XPS、 SEM、 AFM 和 HRTEM 对涂层的成分、形貌及微观结构进行表征分析。 并用纳米压痕硬度计和球盘式摩擦测试仪分别研究了涂层的硬度和摩擦磨损性能。 研究结果表明:TiBN/ TiAlSiN 涂层呈现一种非晶相包裹纳米多晶相的微观结构形态,工作气压越高,涂层表面越趋于光滑;涂层在 1. 0 Pa 工作气压下涂层显微硬度值达到 38 GPa;在 2. 0 Pa 的工作气压下,涂层显微硬度值约 34 GPa,摩擦因数低于 0. 29。 与 TiBN 和 TiAlSiN 涂层相比,TiBN/ TiAlSiN 纳米多层涂层的机械、摩擦学性能更加优越,这为应用在干式切削、磨削工具领域的硬质润滑多层涂层的制备与研究指明了一条方向。     

电弧离子镀制备TiBN纳米复合涂层

目的在纯N_2气氛环境下,低温制备TiBN纳米复合涂层,为TiBN涂层工业化生产积累科学数据。方法采用离子源增强阴极电弧离子镀系统,在硬质合金衬底上制备TiBN纳米复合涂层,系统研究了N_2气压对TiBN涂层晶体结构、表面形貌、硬度和耐磨性能的影响。结果 N_2气压对TiBN纳米复合涂层的晶体结构、表面形貌、硬度及摩擦系数的影响明显。随着N_2气压的升高,TiBN涂层中的TiN晶相逐渐增多,TiB_2晶相逐渐减少,为TiN晶粒和TiB_2晶粒镶嵌于非晶BN基体的复合结构。在0.5 Pa气压下,涂层硬度达3150HV。对于对磨材料硬质合金而言,TiBN涂层的摩擦系数为0.4左右。结论离子源增强电弧离子镀技术可以用于TiBN涂层的制备,制备出的TiBN涂层为纳米晶镶嵌于非晶的纳米复合涂层,涂层的显微硬度较高。在TiBN纳米复合涂层的工业化生产中,沉积N_2气压不宜偏高。     

纳米复合Ti-B-N薄膜的结构和摩擦学性能

研究了射频等离了体辅助化学气相沉积（PCVD）技术获得的Ti-B-N薄膜的组织结构和力学性能。结果发现，B元素的加入使薄膜中出现TiN纳米晶和BN非晶（nc-TiN／a-BN）的复合结构，其硬度显著高于TiN薄膜，最高可达40GPa。用球盘式摩擦磨损实验考察了薄膜的磨损特性。结果表明：与TiN薄膜相比，Ti-B-N薄膜抗磨损性能有显著提高，磨损机制与TiN薄膜不同，摩擦系数较TiN稍高。     

TiN及TiSiN涂层在海水环境下的摩擦学行为研究

目的对比研究海水环境下Ti N及Ti Si N涂层与Al2O3对磨的摩擦磨损行为。方法采用多弧离子镀技术在316L不锈钢及单晶硅片上制备Ti N及Ti Si N涂层。利用场发射扫描电子显微镜(SEM)、X射线衍射仪(XRD)及X射线光电子能谱仪(XPS)分析了涂层的截面形貌及化学组织成分。选择纳米压痕仪测量了Ti N及Ti Si N涂层的硬度及弹性模量,使用UMT-3往复式摩擦试验机研究了人工模拟海水环境下Al2O3与Ti N及Ti Si N涂层对磨后的摩擦磨损行为,并采用扫描电镜(SEM)、电子能谱(EDS)及表面轮廓仪来深入分析了磨痕的摩擦磨损情况。结果研究表明,Ti N涂层的硬度为32.5 GPa,当Si元素掺入涂层以后,Ti Si N涂层的硬度提高到了37 GPa。同时,较之于Ti N涂层,Ti Si N涂层的腐蚀电流密度下降了一个数量级。在摩擦实验中,Ti N涂层的摩擦系数和磨损率分别为0.35和5.21×10-6 mm3/(N·m),而Ti Si N涂层的摩擦系数和磨损率均有明显下降,分别为0.24和1.96×10-6 mm3/(N·m)。结论 Si元素掺杂后能显著提高Ti N涂层在海水环境下的摩擦学性能,主要归因于结构的致密,硬度、韧性、抗腐蚀性的提高及润滑相的形成。     

Influence of Si content and growth condition on the microstructure and mechanical properties of Ti-Si-N nanocomposite films

Thin films of Ti-Si-N have been prepared by ion beam assisted deposition (IBAD) from two Ti and Si targets. The silicon concentration in the deposited coatings is varied between 0 and 23.7 at.%. The influence of Si content and growth conditions on the microstructure and mechanical properties were investigated using XPS, AFM, XRD and nanoindenter. These nanocomposite coatings exhibit improved mechanical properties in comparison with TiN deposited under the same condition. The hardness measured by nanoindentation reached 42 GPa in Ti-Si-N films containing 11.32 at.% of Si, whereas TiN films only had a value of about 18 GPa. AFM showed that the finest grain size of Ti-Si-N appeared to be 5 nm when Si content was 11.32 at.%. From XPS and XRD results, the microstructures of the high hardness samples were found to consist of nanocrystal TiN grains and amorphous Si₃N₄.     

A comparative study of titanium nitrides, TiN, TiNbN and TiCN, as coatings for biomedical applications

A strategy used to reduce wear of the ultra high molecular weight polyethylene (UHMWPE) component of orthopedic joint implants has been to coat the metallic part with a hard ceramic layer. The advantage of this procedure is to reduce both wear and ion release of the metal while keeping a high mechanical resistance. In the present study, the performance of three titanium nitride coatings: TiN, TiNbN, and TiCN for biomedical applications was assessed in terms of their surface properties and cytotoxicity. The morphology, chemical composition, and wettability were determined through atomic force microscopy (AFM) imaging, X-ray photoelectron spectroscopy (XPS) and contact angle measurement, respectively. The tribological behaviour of the coatings rubbing against UHMWPE in lubricated conditions was investigated using a pin-on-disk apparatus. Albumin adsorption on the three coatings was studied with a quartz crystal microbalance with dissipation (QCM-D) and AFM scratching. Cytotoxicity was determined both in direct or indirect contact of the cells with the coating materials. The results demonstrate that the three coatings have similar surface properties and are not cytotoxic. TiNbN seems to have the best tribological performance in the presence of albumin, although albumin adsorption is slightly higher on TiN.     

Effect of prior plasma nitriding applied to a hot-work tool steel on the scratch-resistant properties of PACVD TiBN and TiCN coatings

Ternary TiBN and TiCN coatings on a hot-work tool steel substrate with and without plasma nitriding (PN) prior to plasma-assisted chemical vapour deposition (PACVD) were investigated. Compositional analysis with a radio frequency glow discharge optical emission spectroscope (rf-GDOES) showed mixtures of TiBN + TiN and TiCN + TiN in the PACVD TiBN and TiCN coatings, respectively. Each coating layer had a compositional gradient across the coating depth and slightly into the substrate. The microhardness profiles (HV_0.1) of the substrate with and without PN from the interface with the coating to the substrate core were determined. The depth of the effective nitrided diffusion layer was confirmed from the examination of its optical microstructure. The adhesion of these two coatings to the substrate was evaluated through scratch tests in the progressive mode. It was found that with increasing load, both of the coatings on the substrate with and without prior nitriding deteriorated in the same failure modes. Critical loads corresponding to the first microcracking related to cohesive failure, spallation related to adhesive failure, breakthrough and worn out were determined and used to quantify the scratch resistance of these coatings. With PN prior to PACVD, both the cohesion and adhesion properties of the TiBN and TiCN coatings were remarkably improved. This improvement was attributed to a functionally gradient hardness configuration from the coating through the nitrided diffusion layer to the substrate.     

微波-熔盐热处理在CBN表面形成TiN类石墨烯晶体

用Ti和CBN粉体，通过微波-熔盐处理法在CBN表面反应生成氮化物材料，利用XRD、SEM和EDS对涂层的化学组成、相组成和微观结构进行分析和表征。结果表明:经过熔盐处理，在CBN表面形成TiN、Ti₂N、TiN_0.3和TiB₂组织。粗粒度的CBN表面形成的涂层厚度约2.8 μm，涂层表面有许多微小孔洞；当CBN较细时，CBN表面形成纳米花蕾状组织，花蕾状涂层组织由许多氮化钛纳米棒和片状组织构成。此外，CBN颗粒间还存在许多TiN类石墨烯晶体组织，厚度约40~90 nm。      

The preparation of calcium phosphate coatings on titanium and nickel–titanium by rf-magnetron-sputtered deposition: Composition, structure and micromechanical properties

Thin calcium phosphate coatings with a thickness of 0.09 to 2.7 µm were prepared by radio-frequency magnetron sputtering deposition on NiTi and Ti substrates at a substrate temperature of 500 °C in argon atmosphere. Scanning electron microscopy (SEM) showed that the surface structure is uniform and dense without visible defects (pores and microcracks). Rutherford backscattering spectroscopy (RBS) and energy-dispersive X-ray spectroscopy (EDX) confirmed that the coating contains calcium, phosphorus, and oxygen with a uniform composition. Crystallographically, the coating consists of crystalline hydroxyapatite which is also supported by infrared spectroscopy. The mechanical characteristics of the coating were measured by nanoindentation (Vickers indenter), giving a nanohardness of 10 GPa and a Young's modulus of 110 GPa. The strength of adhesion of the calcium phosphate coating to the metallic substrates depended on the coating's thickness and decreased for a thickness larger than 1.6 µm. No difference was observed between NiTi and Ti substrates.     

Characterization of nitride coatings on high density graphite deposited by magnetron sputtering

Cathode deposit consolidation operation after electrorefining of spent metallic fuels of fast breeder reactors involves melting of U and Pu at 1300 °C after distillation of occluded chloride salt and Cd, in graphite crucibles. Nitride coatings possessing high hardness, melting point and thermodynamic stability against reactive materials and molten LiCl-KCl salts have greater potential for coating the graphite crucibles. In the present study nanocrystalline TiN, ZrN and Ti-Si-N coatings were deposited on high density graphite disc and crucible samples by DC/RF magnetron sputtering. The coated samples were characterized by SEM, GIXRD and AFM. The results indicated that coatings with uniform thickness of 3 to 6 µm were deposited on high density graphite which adheres well to the substrate. The surface morphology of TiN, ZrN and Ti-Si-N coatings examined by SEM and AFM showed the presence of spherical nanoparticles of nitrides getting agglomerated into clusters. Characterisation of nitride coated crucibles was carried out before and after uranium melting by induction heating to simulate cathode processor crucible conditions. TiN and Ti-Si-N coating appears to offer better stability, ease of ingot release and coating adhesion. The paper highlights the results of the present investigation.     

Preparation and corrosion behavior of electrodeposited Ni–TiN composite coatings

Ni–TiN composite coatings were successfully prepared by direct current (DC), pulse current (PC) and ultrasonic pulse current (UPC) deposition methods. The morphology, mechanical properties and the corrosion behavior of Ni–TiN composite coatings were investigated using atomic force microscope (AFM), scanning electronic microscope (SEM), X-ray diffraction (XRD) and gravimetric analysis. The results show that the Ni–TiN composite coatings synthesized by UPC deposition method possess a compact and exiguous surface morphology. The XRD results demonstrate that the average grain diameter of Ni and TiN in composite coating prepared by UPC deposition is 52.6 and 35.7 nm, respectively. In the corrosion tests, the coating prepared by UPC deposition exhibits the best corrosion resistance, whereas the coating fabricated by DC deposition suffers the most serious damage.     

Hard and wear-resistant titanium nitride coatings for cemented carbide cutting tools by pulsed high energy density plasma

Hard and wear-resistant titanium nitride coatings were deposited by pulsed high energy density plasma technique on cemented carbide cutting tools at ambient temperature. The coating thickness was measured by an optical profiler and surface Auger microprobe. The elemental and phase compositions and distribution of the coatings were determined by Auger microprobe, x-photon electron spectroscope, and X-ray diffractometer. The microstructures of the coatings were observed by scanning electron microscope and the roughness of the sample surface was measured by an optical profiler. The mechanical properties of the coatings were determined by nanoindentation and nanoscratch tests. The tribological properties were evaluated by the cutting performances of the coated tools applied in turning hardened CrWMn steel under industrial conditions. The structural and mechanical properties of the coatings were found to depend strongly on deposition conditions. Under optimized deposition conditions, the adhesive strength of TiN film to the substrate was satisfactory with the highest critical load up to more than 90 mN. The TiN films possess very high values of nanohardness and Young’s modulus, which are near to 27 GPa and 450 GPa, respectively. The wear resistance and edge life of the cemented carbide tools were improved dramatically because of the deposition of titanium nitride coatings.     

Syntheses and mechanical properties of Ti-B-C-N coatings by a plasma-enhanced chemical vapor deposition

Quaternary Ti-B-C-N films were synthesized on AISI 304 and Si wafer by a PECVD technique using a gaseous mixture of TiCl₄, BCl₃, CH₄, Ar, N₂, and H₂. The microstructure of Ti-B-C-N films was characterized by instrumental analyses of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HRTEM) in this work. Our Ti-B(9 at.%)-C-N coatings had a fine composite microstructure consisting of nano-sized Ti(C,N) crystallites surrounded by amorphous BN phase. The micro-hardness of Ti-B-C-N coatings steeply increased from ∼ 21 GPa of Ti-C-N up to ∼ 42 GPa of Ti-B(9 at.%)-C-N films. In addition, Ti-B-C-N coatings showed the lowest average friction coefficient compared with other coatings of TiN, TiC, and Ti-C-N coatings prepared under the same PECVD condition. A systematic investigation of the microstructure and mechanical properties of Ti-B-C-N coatings with various boron contents is reported in this paper.     

Wear characteristics of TiC, Ti(C,N), TiN and Al2O3 coatings in the turning of conventional and Ca-treated steels

The wear characteristics of single layers of TiC, Ti(C,N), TiN and Al₂O₃ were investigated during turning of conventional and Ca-treated quenched and tempered Al-killed steels. The experimental coatings were deposited using chemical vapour deposition (CVD) or moderate temperature CVD (MTCVD) on cemented carbide substrates of a single composition and the coatings were of similar thicknesses (7 ± 1 μm). The wear mechanisms and layer formation were studied using scanning electron microscopy, optical microscopy and X-ray diffraction. Inclusion modification appeared to be an effective means of enhancing machinability and all experimental coatings exhibited about 20% better performance as a result of Ca-treatment. In particular, the crater wear of the experimental coatings — excluding Al₂O₃ — was clearly reduced. Comparative cutting tests revealed important differences between the coating materials. Wear mechanisms of the experimental coatings are discussed in detail.     

不同气氛下电火花沉积钛合金涂层的组织性能

分别在氮气、氩气和空气3种气氛下,在45钢上电火花沉积制备TC4钛合金涂层。利用OM、SEM、EDS、XRD、XPS等对钛合金沉积层的微观形貌、组织结构进行分析;利用纳米力学探针仪测试对比沉积层的力学性能;采用CETR摩擦磨损仪测试涂层的耐磨性。结果表明:氮气下电火花沉积生成含TiN及少量TiO和TiO2的陶瓷增强层。氮气中制取的涂层微裂纹较明显,但几无坑蚀和微孔,表面形貌优于氩气和空气下的沉积层。纳米硬度高达15.18GPa,无需增加沉积层厚度,即可获得较高硬度和抗变形能力。其摩擦因数为0.41,磨损量为2.2mg,均远低于45钢,也低于空气和氩气下制备的普通的钛合金涂层,并且改善了钛合金涂层的粘着磨损。