溅射靶功率对类金刚石碳薄膜的结构和性能影响

为改善304不锈钢的性能,扩展其应用范围,采用磁控溅射技术在不同溅射靶功率下激发高纯石墨靶在p(100)单晶硅和304不锈钢表面沉积类金刚石碳薄膜。文章对所制备的系列类金刚石碳薄膜作了Raman光谱、X射线衍射(XRD)、原子力显微镜(AFM)、断口形貌的场发射电镜(FESEM)表征,并评价了其纳米硬度与摩擦磨损行为。结果表明:所制备的类金刚石碳薄膜为典型的非晶态微结构;随着靶功率的增大,类金刚石碳薄膜的sp3键含量先增多后减少,表面粗糙度先降低后升高,硬度与弹性模量先升高后降低;靶功率200 W时类金刚石碳薄膜取得最优性能,纳米硬度为11.4GPa,弹性模量为129.3GPa,摩擦系数为0.17,磨损率为5.2×10-7 mm3(N·m)-1。     

泥沙颗粒表面力学及摩擦性能测试分析

本文对材料纳米力学性能测试方法进行了研究,重点分析了颗粒材料纳米压痕测试的原理和方法.针对纳米压痕测试需求,设计了一种简易制样方法,实测了泥沙粒子表面硬度和弹性模量.并利用应变式直剪仪测试了泥沙颗粒表面摩擦性能.结果表明,泥沙颗粒表面纳米硬度及弹性模量分别为1.94 GPa和30.57 GPa,颗粒表面摩擦系数约为0.65.纳米压痕及直剪试验提供了丰富的颗粒材料近表面弹塑形变形和摩擦信息,是评价泥沙颗粒力学及摩擦性能的有效方法.     

浮法玻璃在线镀复合膜的力学性能

用化学气相沉积法在浮法玻璃上制备了复合薄膜.用台阶仪、纳米压痕和X射线衍射分别测定了薄膜厚度、弹性模量、纳米硬度和室温时薄膜的残余应力.实验结果表明:薄膜厚度为560.7nm,弹性模量为48.33GPa,纳米硬度值为10.65GPa,计算得到薄膜的残余应力值为-0.19GPa.对膜厚、气体的配比、流量、玻璃板的厚度、玻璃基体的化学成分等因素对薄膜残余应力的影响进行了讨论.     

TiAlSiN多层梯度涂层力学及摩擦磨损性能试验研究

利用物理气相沉积(PVD)技术,基于阴极电弧技术在Si片、高速钢试片上制备了TiAlSiN多层梯度涂层。利用洛氏硬度计、X射线衍射仪、透射电子显微镜、纳米压痕仪对涂层的表面形貌、物相结构和力学性能进行表征。通过超精密三维表面轮廓光学测量仪、HSR-2M摩擦磨损试验机测试涂层的摩擦磨损性能。试验结果表明TiAlSiN多层梯度涂层结构致密,各层间界面清晰,主要由柱状的面心立方结构的(Ti,Al)N相组成。涂层与基体的结合力达到工业等级HF1,具有良好的膜基结合力,其硬度为27.7 GPa,弹性模量为338.0 GPa,具有较高的硬度和弹性模量。TiAlSiN多层梯度涂层的摩擦系数为0.54,磨损率为7.06×10~3μm~3/(N·m),主要磨损机制为磨粒磨损和轻微粘着磨损。     

纳米压痕法研究金刚石薄膜的力学性能

用热丝化学气相沉积法在硅基体上制备了大面积硼掺杂金刚石薄膜,硼的浓度大约为2×10~(20)/cm3。利用纳米压痕仪及其附件研究了薄膜和纳米划擦有关的力学性能。结果表明:薄膜具有较高的硬度,平均硬度约为30GPa,弹性模量约为419GPa;薄膜与基体的结合强度较高,薄膜发生剥落的第一次破坏力大约是4N。比较而言,薄膜中心区域的硬度高于边缘,结合强度则相反。     

烧结温度对ZrO2薄膜表面形貌及力学性能的影响

采用溶胶-凝胶法在玻璃基体表面制备了经300℃,400℃和500℃烧结热处理的ZrO2薄膜.利用X射线衍射仪、原子力显微镜和纳米压痕仪研究了烧结温度对ZrO2薄膜表面形貌和力学性能的影响.实验结果表明,随着烧结温度的增加,ZrO2的晶体结构由少量的单斜晶相逐渐转变为单斜晶相和四方晶相的混合相.薄膜表面形貌逐渐改善,薄膜的表面粗糙度和颗粒度依次减小,薄膜的表面粗糙度分别为10.5 nm、7.2 nm和5.6 nm,ZrO2的粒径分别为188 nm、153 nm和130 nm.ZrO2薄膜的弹性模量和硬度都显著提高,薄膜的弹性模量分别为89.6 GPa、114.2 GPa和128.9 GPa,薄膜的硬度分别为7.6 GPa、10.3 GPa和15.1 GPa.     

溅射功率对二氧化锆薄膜结构及力学性能的影响研究

为了研究溅射功率对二氧化锆薄膜结构及力学性能的影响,使用射频反应磁控溅射技术在常温下以玻璃为基底使用不同功率镀制了800 nm左右的ZrO2薄膜.利用X射线衍射仪(XRD)和扫描电子显微镜(SEM)对样品结晶情况,表面和断面形貌进行表征,结果显示镀制的ZrO2薄膜均为单斜晶体,晶粒尺寸变化不大;随着功率的升高,薄膜从纳米晶结构转变为柱状晶结构.使用纳米压痕仪对薄膜表面进行硬度和弹性模量测试,发现随着功率升高,硬度和弹性模量均出现上升趋势,进一步增加功率出现下降,再上升的变化;在沉积功率为65 W时,可得到厚度为800 nm,弹性恢复量,硬度,弹性模量和塑性指数均最高,分别为88.55％,25.42 GPa,228.6 GPa和0.314的ZrO2薄膜.不同的溅射功率会镀制出不同结构的二氧化锆薄膜,在常温低功率溅射条件下二氧化锆薄膜结构是影响其力学性能的重要因素.     

载重汽车销轴表面改性及其摩擦磨损性能的研究

在载重汽车销轴基材40Cr钢表面制备Ni-WC纳米复合镀层,实现表面改性,以期提高销轴表面的摩擦磨损性能。观察并分析了纳米复合镀层的表面形貌和微观结构,检测了纳米复合镀层的结合强度、硬度及摩擦磨损性能。结果表明:纳米复合镀层表面较平整、结构致密,与基材结合牢固,其硬度平均值为6 081MPa,约为基材的1.3倍;其平均摩擦因数约为0.35,磨损失重约为1.83mg,均比基材的低。低孔隙率、致密结构和高硬度,使纳米复合镀层具有良好的摩擦磨损性能。     

基于粘着摩擦理论的塑料微观摩擦特性研究

利用纳米压痕仪测试ABS塑料的弹性模量,为了研究塑料材料微观摩擦性能,设计了一套测试制样方案,采用纳米划痕技术实测了ABS塑料的微观摩擦性能,并结合粘着摩擦理论对塑料摩擦特性进行了分析。纳米压痕结果,ABS塑料弹性模量均值约为4.20 GPa;纳米划痕结果,弹性接触和塑性接触时摩擦因数分别约为0.1和0.25;对比理论分析和实验结果发现,粘着摩擦理论用于解释塑料材料微观摩擦行为是可行的。     

纳米颗粒增强摩擦材料摩擦学性能研究

以丁腈橡胶改性酚醛树脂为基体,芳纶纤维、玻璃纤维为增强纤维,选用不同类型的纳米颗粒作为填料设计摩擦材料组分配比,并通过热压烧结制备摩擦材料。通过摩擦磨损试验机测试其在干摩擦条件下的摩擦学性能,并用扫描电镜(SEM)对材料的磨损形貌进行观察分析,以研究不同类型的纳米颗粒对摩擦材料性能的影响。研究表明:在干摩擦条件下,经过纳米颗粒改性的摩擦材料摩擦系数、硬度比未改性的材料有不同程度的提高,同时磨损率有很大程度的降低;纳米颗粒改性的摩擦材料摩擦系数、磨损率变化趋势具有一致性,均随着实验载荷、滑动速度的增大而逐渐减小;纳米颗粒改性后的摩擦材料磨损机理表现为疲劳磨损与磨粒磨损并存,而未改性的材料磨损机理主要表现为疲劳磨损。     

Microstructure and properties of the AlCrMoZrTi/(AlCrMoZrTi)N multilayer high-entropy nitride ceramics films deposited by reactive RF sputtering

The AlCrMoZrTi/(AlCrMoZrTi)N multilayer high-entropy nitride ceramic films (HENCFs) fabricated by reactive RF magnetron sputtering presented (200) preferentially oriented FCC crystal structures. With the increase in the modulation period, the nitrogen content and surface roughness of the multilayer films gradually increased, the template effect between the nanocrystalline and amorphous forms was weakened, and the multilayer interface structure decreased. The S4 film with a modulation period of 1500 nm had the highest hardness and modulus (16.6 and 225.7 GPa, respectively) and the highest H/E* and H³/E*² values. The results of friction experiments showed that the S1 film with the smallest modulation period had a stable friction coefficient and small wear rate on both Si and Cu substrates, and it exhibited the best friction and wear performance due to its low surface roughness, high toughness and compressive yield resistance, and dense multilayer structure. The friction mechanisms of the HECNFs on Si and Cu substrates were mainly adhesive wear, abrasive wear, and a small amount of oxidative wear.     

Investigation of the tribological and biomechanical properties of CrAlTiN and CrN/NbN coatings on SST 304

This study examines the influence of thin layer coatings of CrAlTiN and CrN/NbN, deposited via physical vapor, on the biocompatibility, mechanical, tribological, and corrosion properties of stainless steel 304. The microstructure and morphology of the thin CrAlTiN and CrN/NbN layers were characterized by scanning electron microscopy (SEM), EDX, and X-ray diffraction. The pin on disc wear test was performed on bare and metal-nitride coated SST 304 under a 15 N load at 60 rpm and showed that the wear rates of the thin CrAlTiN and CrN/NbN film coatings were lower than the bare substrate wear ratio. The coefficients of friction (COFs) attained were 0.64, 0.5, and 0.55 for the bare substrate, CrN/NbN coating, and CrAlTiN coating, respectively. Nano indentation tests were also performed on CrAlTiN-coated and CrN/NbN-coated SST 304. The nanohardnesses and Young's moduli of the coated substrates were 28 GPa and 390 GPa (CrN/NbN-coated) and 33 GPa and 450 GPa (CrA1TiN-coated), respectively. For comparison, the nanohardness and Young's modulus of the uncoated substrate were 4.8 GPa and 185 GPa, respectively. Corrosion tests were conducted, and the behaviors of the bare and metal nitride-deposited substrates were studied in CaCl₂ for seven days. The corrosion Tafel test results showed that the metal-nitride coatings offer proper corrosion resistance and can protect the substrate against penetration of CaCl₂ electrolyte. The CrN/NbN-coated substrates showed better corrosion resistance compared to the CrAlTiN-coated ones. In evaluating the biocompatibility of the CrAlTiN and CrN/NbN coatings, the human cell line MDA-MB-231 was found to attach and proliferate well on the surfaces of the two coatings.     

硅灰石与纳米MoS2对丙烯酸酯橡胶摩擦磨损性能的影响

采用无转子硫化仪、环-块式摩擦试验机、电子和光学显微镜等分析表征手段,考察了硅灰石及其与纳米二硫化钼(MoS2)并用对丙烯酸酯橡胶(ACM)摩擦磨损性能的影响。结果表明,随着硅灰石用量的增加,改性ACM硫化胶的摩擦因数逐渐降低,而磨损体积呈现出先降低后升高的趋势;当硅灰石用量为35 phr时,硫化胶具有较小的摩擦因数和最好的耐磨性。在35 phr硅灰石改性ACM基础上添加1 phr纳米MoS2时,硫化胶的摩擦因数和磨损体积分别下降到0.4和1.54 mm3,表现出最低的摩擦因数和磨损体积,同时还保持较好的硫化和力学性能。纳米MoS2与硅灰石并用改性ACM时,硫化胶表现出轻微的磨粒磨损特征,磨损面平整光滑,形成的转移膜薄且完整均匀。     

Study on wear and friction behavior of graphite flake‐filled PTFE composites

The wear rate and coefficient of friction for graphite flake (GF)‐filled polytetrafluoroethylene (PTFE) composites were evaluated on a pin‐on‐disk wear tester under dry conditions. Scanning electron microscopy showed significant reduction in the abrasive wear of the composites. The wear rates of 5 and 10 wt % GF composites were reduced by more than 22 and 245 times, respectively, at sliding speed of 1 m/s. With increasing sliding distance from 1 to 8 km, the wear rate of pure PTFE decreased by 1.4 times whereas that of composites, it decreased up to three times. The significant decreased in wear rate and coefficient of friction might be attributed to the formation of a thin and tenacious transfer film on the counter‐surface. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Influence of WS2 content on high temperature wear performance of magnetron sputtered TiN-WSx thin films

TiN-WS_x thin films with varying WS_x content were co-deposited by reactive magnetron sputtering. GAXRD analyses showed that the addition of 4 at.% WS_x led to loss of crystallinity of TiN phase and a complete amorphous characteristic was manifested upon incorporation of 19 at.% WS_x. Nanohardness results indicated that TiN-WS_x containing 4 and 19 at.% WS_x presented 19.7 GPa and 18.4 GPa, respectively, following the rule of mixtures. Friction coefficient and wear rates measured in reciprocated tribological tests revealed that TiN-WS_x coatings present an improved tribological performance when compared to pure TiN thin film at room temperature, registering friction coefficient of 0.42 ± 0.05 and 0.19 ± 0.03 for samples with 4 and 19 at.% WS_x, respectively. Wear tests at high temperatures evidenced that sample with 4 at.% WS_x did not provide advanced protection to substrate at 343 K and above due to deterioration. On the other hand, coating with 19 at.% WS_x maintained low friction coefficient up to 343 K, registering an optimum wear rate of 0.86 × 10⁻¹⁷ m²/N with no cracking occurrence.     

Enhanced mechanical and tribological properties of oscillatory pressure sintered WC–GNPs composites

It remains as a challenge to develop binderless WC ceramics that integrate high mechanical properties and low friction wear. Here, we report the preparation of strong and tough WC ceramics with low wear rate by adding graphene nanoplatelets (GNPs) and using oscillatory pressure sintering (OPS) process. The introduced GNPs lead to the formation of nearly fully dense composites with the aid of an oscillatory pressure. The OPS-prepared WC–0.3-wt% GNPs composites reached a high flexural strength, hardness, and fracture toughness, being up to 1420 MPa, 24.9 GPa, and 6.89 MPa m^1/2, respectively. Moreover, a low friction wear rate of 3.17 × 10⁻⁷ mm³ N⁻¹ m⁻¹ is achieved for such composites, which can be ascribed to the formation of a friction lubrication film during dry sliding friction process and their higher mechanical properties.     

Tribology–Structure Relationships in Silicon Oxycarbide Thin Films

Silicon oxycarbide is a versatile material system that is attractive for many applications because of its ability to tune properties such as chemical compatibility, refractive index, electrical conductivity, and optical band gap through changes in composition. One particularly intriguing application lies in the production of biocompatible coatings with good mechanical properties. In this paper, we report on the wide range of mechanical and tribological property values exhibited by silicon oxycarbide thin films deposited by reactive radio frequency magnetron sputtering. Through a change in oxygen partial pressure in the sputtering plasma, the composition of the films was controlled to produce relatively pure SiO₂, carbon-doped SiC, and compositions between these limits. Hardness values were 8–20 GPa over this range and the elastic modulus was measured to be between 60 and 220 GPa. We call attention to the fit of the mechanical data to a simple additive bond-mixture model for property prediction. Tribological parameters were measured using a ball-on-disk apparatus and the samples exhibited the same general trends for friction coefficient and wear rate. One film is shown to produce variable low friction behavior and low wear rate, which suggests a solid-state self-lubrication process because of heterogeneity on the nanometer scale.     

Influence of Re-adhesion on the Wear and Friction of Glass Fibre-Reinforced Polyester Composites

Based on the well-known pin-on-disc test rig, a new test setup for online measuring of wear and friction behaviour of polymer matrix composites has been developed. In contrast to a traditional friction-and-wear test rig, a steel pin and composite disc are used for studying the influence of wear debris and fibre orientation. During sliding, a thin adhesive film is possibly formed on the wear track of a composite disc, consisting of wear debris that is squeezed under the steel pin and that finally smoothens onto the composite surface. By optical microscopy, it was observed that most of the debris particles originate from the edges of the wear track. The thin film deforms continuously, with large and dark wear particles observed at the edge of the wear track. A lower coefficient of friction is achieved when the particles are re-adhered to the mating surface. The film formation mechanism depends on the normal force, sliding velocity, and bulk composite structure: because pultruded composite profiles are presently used with a layered structure, a change in film properties is observed depending on the wear depth.     

Influence of Re-adhesion on the Wear and Friction of Glass Fibre–Reinforced Polyester Composites

Based on the well-known pin-on-disc test rig, a new test setup for online measuring of wear and friction behaviour of polymer matrix composites has been developed. In contrast to a traditional friction-and-wear test rig, a steel pin and composite disc are used for studying the influence of wear debris and fibre orientation. During sliding, a thin adhesive film is possibly formed on the wear track of a composite disc, consisting of wear debris that is squeezed under the steel pin and that finally smoothens onto the composite surface. By optical microscopy, it was observed that most of the debris particles originate from the edges of the wear track. The thin film deforms continuously, with large and dark wear particles observed at the edge of the wear track. A lower coefficient of friction is achieved when the particles are re-adhered to the mating surface. The film formation mechanism depends on the normal force, sliding velocity, and bulk composite structure: because pultruded composite profiles are presently used with a layered structure, a change in film properties is observed depending on the wear depth.     

超细羟基硅酸镁粉体在磨损后钢表面的自修复特性(英文)

使用AMSLER摩擦磨损试验机进行摩擦磨损试验,研究超细羟基硅酸镁粉体作为润滑油添加剂在磨损后摩擦副表面的自修复特性。使用扫描电子显微镜、能谱仪和X射线光电子能谱分析了2种润滑油润滑下磨损后的45#钢环的表面形貌和化学组成。结果显示:经50h纯润滑油润滑后在45#钢表面出现了大量的划痕,而之后经50h含添加剂润滑油润滑后这些划痕被自修复膜所覆盖。这层自修复膜主要由Fe,O,Si,C和Mg构成,这表明粉体添加剂在摩擦磨损过程中可以向磨损的金属表面发生转移。自修复膜的形成原理是这些粉体可以吸附到钢的磨损后新鲜表面,之后在接触表面的剪切应力下铺展于磨损后金属表面。这层自修复薄膜可以明显提高金属摩擦副的抗磨损性能。