基体表面粗糙度对磁控溅射TiN涂层界面结合力的影响

利用球与平面的赫兹接触应力分布的经验修正公式∧［1］,对磁控溅处理前的基体表面粗糙度对沉积层和基体的界面结合力进行了研究,并和其他涂层界面结合力的测量方法方法进行了比较。结果表明：基体表面粗糙度对界面结合力有很大影响,表面粗糙度的改善有利于TiN层/基体的界面结合力的提高,同时改善了TiN层的摩擦学性能。     

基体负偏压对CrAlN涂层组织和性能的影响

采用真空多弧离子镀技术,使用Cr30Al70(原子分数)复合靶,在不同的基体负偏压下,在不锈钢基体上制备了一系列CrAlN涂层;采用能谱仪、X射线衍射仪、扫描电子显微镜、粗糙度仪、显微硬度仪、摩擦磨损试验机和划痕仪等系统分析了涂层的成分、表面形貌、相结构、粗糙度、显微硬度、摩擦磨损性能和界面结合性能。结果表明:随着负偏压的增大,涂层中x(Cr)/x(Cr+Al)的比值先增大后减小,当负偏压为150V时,该值达到最大,并与靶材成分接近;基体负偏压为200V时,涂层的表面粗糙度最大,涂层结晶度、硬度最佳,晶体相为固溶铬的面心立方AlN;涂层的摩擦磨损性能不仅与涂层的表面粗糙度相关,还与涂层非晶相中铝元素的含量以及涂层的内应力大小密切相关;界面过渡层制备工艺相同时,基体偏压对涂层和基体之间的界面结合性能影响较小。     

基体偏压对Cr/DLC薄膜结构及力学性能的影响

采用高功率脉冲磁控溅射方法在不同基体偏压下的钢基体上沉积含Cr过渡层的DLC薄膜.利用原子力显微镜、场发射扫描电镜、Raman光谱、动态超显微硬度计和划痕仪对薄膜的表面形貌、截面形貌、结构成分、力学性能进行表征.结果表明:随着基体偏压的增大,薄膜表面更加平整,表面粗糙度减小;不同基体偏压下制备的DLC薄膜与基体结合良好...     

C离子注入对硬质合金刀具TiN涂层性能的影响

在硬质合金刀具上沉积了PVD—TiN涂层,并采用C离子注入技术对其进行表面改性处理。对涂层截面的微观形貌、显微硬度以及与基体附着力的测试结果表明,C离子注入可使TiN涂层的显微组织细密均匀化,并能明显提高涂层的显微硬度以及与基体的附着力。     

Ti/TiN复合膜工艺优化及性能研究

利用正交试验和极差分析方法，分析了多弧离子镀Ti／TiN复合膜中工艺参数（弧电流、氮气分压、基体负偏压、钛过渡层厚度）对Ti／TiN复合膜的纳米硬度和膜与基体的结合力的影响及主次关系，并通过正交试验对工艺参数进行了优化。研究表明，氮气分压和弧电流是影响Ti／TiN复合膜纳米硬度的2个最主要因素，膜层与基体的结合力随着弧电流的增加而下降；升高基体负偏压，虽然可以提高Ti／TiN复合膜纳米硬度和膜与基体的结合力，但是高负偏压将急剧升高基体温度，可能导致基体退火；沉积一定厚度的钛过渡层可以显著提高TiN膜层与基体的结合力。     

硬质合金基体上TiN与TiAlN涂层冲蚀磨损特性研究

采用离子束辅助真空脉冲过滤弧离子镀技术,在硬质合金YG6基体上沉积两种氮化物涂层TiN、TiAlN,检测了涂层的微观结构及其主要物理机械性能。对两种涂层进行气体冲蚀磨损试验,利用扫描电子显微镜(SEM)对冲蚀表面进行观察,获得涂层冲蚀形貌特征。通过检测涂层的冲蚀磨损量和磨损率,分析涂层的冲蚀磨损性能,表明TiAlN涂层比TiN表现出了更强的抵抗冲蚀磨损的能力。通过分析两种涂层的冲蚀表面形貌特征,发现两种涂层材料的冲蚀去除机制有所不同。TiN涂层表现出典型的脆性断裂去除特点,而TiAlN涂层主要呈现微切削和疲劳断裂的特征。     

TiN/TiSiN复合涂层显微结构与力学性能研究

采用工业用直流脉冲等离子体增强化学气相沉积(PCVD)法在硬质合金刀具基体上制备了TiN和TiN/TiSiN复合涂层.对TiN涂层和不同沉积温度下制备的三种TiN/TiSiN复合涂层的微观结构和力学性能进行了对比研究.结果表明:随着沉积温度的升高,TiN/TiSiN复合涂层的结合力增大;沉积温度为550℃时,TiN/T...     

NiTi合金表面改性及其微动磨损性能研究

采用多弧离子镀技术在NiTi形状记忆合金表面制备TiN涂层。利用SRVⅢ摩擦磨损试验机研究NiTi合金表面改性后在37℃Hank’s模拟体液中微动磨损性能,分析法向载荷对TiN合金磨损机制的影响规律。利用SEM扫描电镜及能谱考察磨损表面形貌,结果表明：制备的TiN涂层表面致密均匀,无明显缺陷。说明TiN涂层可有效提高基体的耐磨性能,其磨损机制主要表现为剥落损伤与磨粒磨损并存。TiN涂层显微硬度为784 HV,远高于基体,TiN/NiTi膜基硬度比缓慢下降,涂层与基体结合强度高。     

偏压对TiBN纳米复合涂层结构及力学性能的影响

采用多弧离子镀技术,在单晶硅和硬质合金衬底上制备Ti-B-N涂层,使用XRD,SEM,硬度计和划痕仪系统研究了偏压对TiBN涂层结构、表面形貌、硬度和附着力的影响。在不同的基体偏压下,涂层表现了(111)面择优生长。-100 V偏压时沉积的TiBN涂层表面最平滑。随着基体偏压升高,TiBN涂层硬度逐渐增大,膜基结合力逐渐减小。-200 V制备的TiBN涂层硬度最大3600 HV,-50 V制备的TiBN涂层膜基结合力接近40 N。     

TiN涂层在一般零件表面的摩擦磨损性能

摩擦磨损现象存在于各类机械设备中,造成了很大的经济损失。选用了一般零件最常用的45#钢作为实验材料,研究45#钢表面沉积TiN涂层后,在摩擦磨损试验机上的摩擦磨损性能。通过实验比较不同载荷、不同转速对TiN涂层的摩擦磨损性能影响,由结果显示,TiN涂层不能降低摩擦系数,但能有效降低基体表面的磨损率。     

工件台偏压对非平衡磁控溅射沉积MoS_2-Ti薄膜的结构与性能影响

采用非平衡磁控溅射技术制备MoS2-Ti薄膜,研究工件台偏压对薄膜结构和性能的影响。利用XRF和XRD分析薄膜的成分和晶相结构,用CSM薄膜综合性能测试仪测试薄膜的厚度、硬度以及膜与基体的结合力,采用球-盘摩擦磨损试验机评价薄膜在真空环境下的摩擦学性能。结果表明:MoS2-Ti薄膜具有明显的(002)优势取向,薄膜中S、Mo原子比及膜厚随偏压的增加而减小,薄膜硬度及膜-基体附着力随偏压的增加而增大,薄膜在真空环境中的平均摩擦因数为0.02,受偏压影响不明显,薄膜寿命受偏压影响明显,当偏压在-100 V内变化时薄膜具有较长的寿命且随偏压的增加而增长,偏压继续增大薄膜耐磨寿命下降明显,当偏压为-200 V时薄膜不具备润滑性能。     

基体表面粗糙度对纳米复合镀层组织及性能的影响

采用电刷镀技术在不同表面粗糙度的W18Cr4V高速钢基体上制备了纳米PTFE和纳米WC颗粒增强的镍基复合镀层,采用扫描电镜对纳米复合镀层的表面和截面形貌进行了观察,研究了基体表面粗糙度对纳米复合镀层耐磨性、耐蚀性和结合强度的影响.结果表明:随着基体表面粗糙度的减小,纳米复合镀层的表面更加平整致密,组织更加细小均匀,镀层厚度减小,镀层中的裂纹数量减少,镀层的耐磨性、耐蚀性和结合强度均得到明显提高.     

Investigation of the performance of carbide cutting tools with hard coatings in hard milling based on the response surface methodology

Machining of hard materials has become a great challenge for several decades. One of the problems in this machining process is early tool wear, and this affects the machinability of hard materials. In order to increase machinability, cutting tools are widely coated with nanostructured physical vapor deposition hard coatings. The main characteristics of such advanced hard coatings are high microhardness and toughness as well as good adhesion to the substrate. In this paper, the influence of hard coatings (nanolayer AlTiN/TiN, multilayer nanocomposite TiAlSiN/TiSiN/TiAlN, and commercially available TiN/TiAlN) and cutting parameters (cutting speed, feed rate, and depth of cut) on cutting forces and surface roughness were investigated during face milling of AISI O2 cold work tool steel (～61 HRC). The experiments were conducted based on 3¹³ factorial design by response surface methodology, and response surface equations of cutting forces and surface roughness were obtained. In addition, the cutting forces obtained with the coated and uncoated tools were compared. The results showed that the interaction of coating type and depth of cut affects surface roughness. The hard coating type has no significant effect on cutting forces, while the cutting force F _z is approximately two times higher in the case of uncoated tool.     

Arc Evaporation of Ti–Al–Ta–N Coatings: The Effect of Bias Voltage and Ta on High-temperature Tribological Properties

Recently, titanium aluminium tantalum nitride (Ti–Al–Ta–N) coatings have been shown to exhibit beneficial properties for cutting applications. However, the reason for the improved behaviour of these coatings in comparison to unalloyed Ti–Al–N is not yet clear. Here, we report on the tribological mechanisms present in the temperature range between 25 and 900 °C for this coating system, and in particular on the effect of the bias voltage during deposition on the tribological response. Based on these results, we provide an explanation for the improved performance of Ta-alloyed coatings. An industrial-scale cathodic arc evaporation facility was used to deposit the coatings from powder metallurgically produced Ti₄₀Al₆₀ and Ti₃₈Al₅₇Ta₅ targets at bias voltages ranging from −40 to −160 V. X-ray diffraction experiments displayed a change with increasing bias voltage from a dual-phase structure containing cubic and hexagonal phases to a single-phase cubic structure. Investigations of the wear behaviour at various temperatures showed different controlling effects in the respective temperature ranges. The results of dry sliding tests at room temperature were independent of bias voltage and Ta-alloying, where the atmosphere, i.e. moisture and oxygen, were the most important parameters during the test. At 500 °C, bias and droplet-generated surface roughness were identified to determine the tribological behaviour. At 700 and 900 °C, wear depended on the coating’s resistance to oxidation, which was also influenced by the bias voltage. In conclusion, Ta-alloyed coatings show a significantly higher resistance to oxidation than unalloyed Ti–Al–N which could be an important reason for the improved performance in cutting operations.     

添加纳米MoS2镍-磷化学复合镀层的制备与微观形貌

运用化学复合镀技术制备出添加纳米MoS2的镍-磷复合镀层.研究了制备过程中镀液中分散剂种类、MoS2添加数量以及镀前试样表面粗糙度对复合镀层的影响.结果表明:十六烷基三甲基溴化铵(CTAB)可以很好地在镀液中分散纳米MoS2,镀液中添加纳米MoS2颗粒的最佳值是2.0 g/L;镀前试样表面粗糙度值过低不利于提高复合镀层中纳米MoS2的复合量.     

Structural, optical and mechanical properties of nanostructure diamond synthesized by chemical vapor deposition

Nanostructure diamond (NSD) films on Si substrate are prepared by microwave plasma enhanced chemical vapor deposition (MPECVD) using methane and hydrogen as the reactants with two-step negative substrate bias (SB). The dependencies of the NSD film morphology, grains, surface roughness, crystal and bonding structures and hardness on the negative SB at the bias-enhanced growth (BEG) step and substrate temperature during growth have been investigated by conducting atomic force microscopy (CAFM), X-ray diffraction (XRD), Raman spectroscopy and nanoindentation. The hardness of the NSD film is found to be as high as 80 GPa with CAFM average and root mean square roughness of 7 and 9 nm, respectively, under optimal negative SB at the BEG step. From the studies of substrate temperature effect, the hardness of the NSD film is as high as 70 GPa, with average and root mean square CAFM roughness of 9 and 11 nm, respectively, which were obtained at a substrate temperature of 500 °C. In both cases, the film hardness was found to be affected by the size of clusters, which are composed of many small NSD particles, the amount of NSD in an amorphous matrix as well as surface roughness. We also synthesized transparent NSD films by MPECVD under optimized single-step growth conditions on quartz substrates, which are scratched with several micrometers diamond powder. A hardness as high as 60 GPa and a maximum transmittance of 60% in the visible light region are achieved for an NSD coating of 1.0 μm thickness with small surface roughness.     

The effect of substrate properties on tribological behaviour of composite DLC coatings

The unique features of DLC coatings in providing low friction and low wear and, at the same time, causing low wear to the counterface make them very attractive in industrial applications, in improving tribological performance of mechanical components on various substrates. In this study, composite DLC coatings have been deposited on sintered ferrous alloy, M42 tool steel, 2618 aluminium alloy, and 6063 aluminium extrusion substrates using the combined CFUBMS–PACVD technique. The effect of mechanical properties of substrate materials on tribological behaviour of the composite DLC coatings has been investigated at various loads on a ball-on-disk wear machine in dry air. A transition load was usually observed for coatings on the various substrates except for the aluminium extrusion; above the transition load the coating was completely destroyed via some spallation/fragmentation process after 2 h sliding, and the wear rate increased dramatically with further increase in load. The coating system on sintered ferrous alloy substrate exhibited the highest transition load among the four types of substrates studied. This is considered to have resulted from the combined effects of the lower elastic modulus of the porous sintered ferrous alloy substrate, which decreases the stress concentrations in the contact region, and the surface roughness and porosity, which enhance the bonding strength between the coating and the substrate under multi-contact conditions. The high elastic modulus of the tool steel substrate leads to tensile stress conditions in the sliding contact region and therefore makes coatings deposited on such a substrate more prone to breakdown/fragmentation, resulting in a transition load close to that for coatings on the soft 2618 aluminium alloy substrate. For coatings on the 6063 aluminium extrusion substrate, significant plastic deformation occurred in the substrate at loads above 1.5 N. However, despite the heavy deformation in the substrate, coatings on this substrate were not scraped off, as were coatings on the 2618 aluminium alloy substrate, even at a load as high as 20 N. The specific wear rate increased continuously with load, no apparent transition load being explicitly identifiable. This study shows that hard DLC coatings can be applied on both hard and soft substrates for improvement of the tribological behaviour of mechanical components.