钛表面激光熔覆NiCr-Ag复合涂层结构及空间摩擦学性能研究

利用激光熔覆技术在钛基材表面制备了NiCr-Ag复合涂层。用XRD、SEM和HRTEM分析了涂层的组成和组织结构,利用空间摩擦学系统对复合涂层在三种模拟空间环境(高真空、原子氧和紫外辐照)以及大气环境下的摩擦磨损性能进行了系统的研究。采用SEM和EDS对磨损后复合涂层和对偶钢球的形貌和元素面分布进行了分析,揭示了复合涂层在模拟空间环境及大气环境下摩擦磨损失效机理。结果表明：复合涂层在大气环境条件下的摩擦磨损性能优于在三种模拟空间环境下的摩擦磨损性能;真空下的辐照对复合涂层的摩擦磨损性能有显著的影响,辐照会增加涂层表面氧化;复合涂层在高真空、原子氧和紫外辐照模拟空间环境下的磨损机理为较严重的粘着磨损、磨粒磨损和塑性变形,在大气环境条件下的磨损机理主要为磨粒磨损。     

钛表面激光熔覆NiCr-Ag复合涂层组织结构及空间摩擦学性能（英文）

利用激光熔覆技术在钛基材表面制备了NiCr-Ag复合涂层。用XRD、SEM和HRTEM分析了涂层的组成和组织结构,利用空间摩擦学系统对复合涂层在3种模拟空间环境(高真空、原子氧和紫外辐照)以及大气环境下的摩擦磨损性能进行了研究。采用SEM和EDS对磨损后复合涂层和对偶钢球的形貌和元素面分布进行了分析,揭示了复合涂层在模拟空间环境及大气环境下摩擦磨损失效机理。结果表明:复合涂层在大气环境条件下的摩擦磨损性能优于在3种模拟空间环境下的摩擦磨损性能;真空下的辐照对复合涂层的摩擦磨损性能有显著的影响,辐照会增加涂层表面氧化;复合涂层在高真空、原子氧和紫外辐照模拟空间环境下的磨损机理为较严重的粘着磨损、磨粒磨损和塑性变形,在大气环境条件下的磨损机理主要为磨粒磨损。     

钛在模拟空间环境下的摩擦学性能

为了明确钛及其合金在空间环境下的摩擦磨损行为,利用中科院兰州化学物理研究所自主研发的空间摩擦学试验系统对钛在模拟空间环境(高真空、原子氧和紫外辐照)下的摩擦磨损性能进行了研究。用X光电子能谱仪(XPS)分析了钛在原子氧辐照后表面元素价态的变化。采用扫描电镜(SEM)对磨损后试样和对偶钢球的磨痕形貌进行分析,利用能量色散光谱仪(EDS)对钢球磨痕元素面分布进行分析,揭示了钛在模拟空间环境下的摩擦磨损失效机理。结果表明:钛在原子氧辐照后表面发生了氧化;钛在大气环境条件下的摩擦磨损机理主要为磨粒磨损和粘着磨损,在高真空、原子氧和紫外辐照模拟空间环境下的磨损机理主要为严重的粘着磨损、磨粒磨损和塑性变形。相比于大气环境条件下,钛在高真空、原子氧和紫外辐照下的粘着磨损加剧,摩擦因数增加。     

TiN/Ag涂层在真空环境下的摩擦学行为

目的 银具有低的剪切强度,可以降低涂层的摩擦磨损,在TiN硬质涂层中引入软金属Ag,以期拓展其在摩擦学领域的应用范围.方法 采用多弧离子镀沉积技术,在SUS304不锈钢基底上成功制备了TiN/Ag复合涂层.利用扫描电子显微镜、纳米压痕仪、RST3划痕仪,分析了TiN/Ag涂层的微观结构和机械性能.利用CSM(大气)和HVTRB(真空)摩擦磨损试验机评估了TiN/Ag涂层的摩擦学性能.结果 TiN/Ag涂层结构致密,厚度为1.2μm,硬度约为28.4 GPa.摩擦学测试表明,真空环境下的摩擦因数远低于大气环境下的摩擦因数,大气环境下的磨损机理主要为粘着磨损与磨粒磨损,而真空环境下主要表现为机械抛光及摩擦转移膜.真空环境下TiN/Ag涂层不同载荷下的摩擦试验表明,1 N载荷条件下,摩擦因数值低至0.07,且涂层发生轻微磨损;3 N载荷条件下,机械能和热应力使得摩擦界面中的Ag发生扩散,摩擦因数迅速增加到0.42左右;5 N载荷条件下,摩擦因数呈现较明显的波动,随着滑动次数的增加,摩擦因数最高达到1.0,涂层表面发生软化形成犁沟效应,而导致涂层失效.结论 TiN/Ag涂层中Ag掺杂可显著降低涂层的内应力,抑制摩擦过程中涂层微裂纹的扩展,适当载荷下能够有效地改善TiN硬质涂层真空下的摩擦学性能.     

激光熔覆NiCoCrAlY/HfB2复合涂层结构及高温摩擦学性能

利用激光熔覆技术在纯钛表面制备了NiCoCrAlY/HfB2复合涂层。用XRD和SEM分析了涂层的组成和组织结构,在SRV-IV微动摩擦磨损试验机上对涂层不同温度下的摩擦磨损性能进行对比测试,采用SEM和三维表面轮廓仪对磨损后试样、对偶球和磨屑的形貌进行了分析。结果表明:NiCoCrAlY/HfB2复合涂层主要组成为NiTi、HfB2、TiB2、Co3Ti、CrTi4和Hf3Ni7相,复合涂层与基材冶金结合,涂层晶体结构主要为块状晶。涂层的平均显微硬度约为850HV0.2,是基材硬度的4.25倍。在20℃、100℃、300℃和500℃摩擦测试温度下涂层的摩擦因数和磨损率随温度的升高而减小,复合涂层的磨损率在10-4～10-5 mm3/Nm数量级,具有较好的高温耐磨性能,涂层的磨损机制主要为磨粒磨损和黏着磨损。     

KS-B高吸收高发射率无机热控涂层低轨环境效应

目的 研究低轨环境对KS-B高吸收高发射无机热控涂层(简称KS-B涂层)性能的影响。方法 对KS-B涂层分别进行总剂量为3.9×10²² atoms/cm²的原子氧辐照、剂量为5000 ESH的真空-紫外辐照、总注量为9.30×10¹¹ p/cm²的真空-质子及总注量为1.108×10¹⁴ e/cm²的真空-电子综合辐照试验,分析空间模拟辐照环境中KS-B涂层太阳吸收比(αS)、半球发射率(εH)、表面形貌、表面组分含量、质量损失率等性能的变化规律,研究KS-B涂层的耐空间环境稳定性。结果 原子氧暴露后,KS-B涂层太阳吸收比增加0.003,半球发射率增加0.004;原子氧辐照后,KS-B涂层表面形貌出现了一定程度的糙化,表面Si、O元素含量下降。初始暴露时,KS-B涂层质量损失率逐渐提高,最终质量损失率为0.96%。真空-紫外辐照后,KS-B涂层太阳吸收比增加0.003,半球发射率无变化。真空-质子及真空-电子辐照前后,KS-B涂层太阳吸收比增加0.001,半球发射率无变化。结论 经历原子氧、真空-紫外、真空-质子及真空-电子模拟辐照后,KS-B涂层的太阳吸收比及半球发射率变化较小,具有较好的耐空间辐照性能,可以满足空间站等低轨航天器的长寿命服役需求。     

纯钛表面激光熔覆铁基耐磨涂层结构及摩擦学性能(英文)

利用激光熔覆技术在纯钛表面制备铁基涂层。用 XRD、SEM、TEM分析涂层的相组成和晶体结构。在UMT-2MT摩擦磨损试验机上对铁基涂层在不同载荷和不同滑动速度下的摩擦磨损性能进行测试。用SEM和3D表面轮廓仪分析铁基涂层磨损后的表面形貌和磨屑形貌。结果表明:钛表面激光熔覆制备的铁基涂层的显微硬度约为860HV0.2,具有优异的耐磨性能,磨损率为(0.70～2.32)×10-6mm3/(N·m),可以显著提高纯钛基材的耐磨性能;涂层的磨损机理为轻微的磨粒磨损和粘着磨损。     

氩弧熔覆原位自生TiC-TiB增强铁基复合涂层组织与性能

以碳粉、钛粉、硼粉和铁粉末为原料,利用氩弧熔覆技术在16Mn钢基材表面成功制备出铁基增强相复合涂层,运用XRD,SEM等分析手段研究了复合涂层的显微组织,利用显微硬度仪测试了复合涂层的显微硬度,并用磨损试验机分析了其在室温干滑动磨损条件下的耐磨性能.结果表明,复合涂层与基体界面无气孔、裂纹,呈冶金结合.复合涂层由TiB,TiC,Fe₂Ti和α-Fe组成.显微硬度和耐磨性测试结果表明,该复合涂层显微维氏硬度高达1000 MPa左右.常温干滑动磨损条件下,复合涂层具有优异的耐磨性.     

45钢基体上激光熔覆Ni60A合金涂层的显微组织和高温摩擦学行为（英文）

采用激光熔覆技术在45号钢基材上制备出无裂纹Ni60A涂层,详细研究涂层显微组织的凝固特性、相组成及相分布。系统评估涂层和基材在不同载荷下滑动对磨GCr15球时的高温摩擦磨损行为。结果表明:涂层显微组织均匀致密,主要由γ(Ni)固溶体、大量的Ni-Ni3B网状共晶、小花状M23C6及不均匀分布于枝晶间共晶组织中的黑点状CrB组成;涂层显微硬度约为基材显微硬度的2.6倍;相同载荷条件下,涂层摩擦因数大于基材摩擦因数,但摩擦过程稳定;在较高载荷条件下(300 g),涂层磨损率为基材的1/6.2;基材磨损机制为粘着磨损、磨料磨损、严重塑性变形及氧化磨损,而涂层磨损机制则为轻微的磨粒磨损和中等程度的氧化磨损。     

等离子喷涂高铬铸铁涂层的摩擦学性能

针对铝合金缸体内壁油性腐蚀环境中的摩擦工况,采用大气等离子喷涂制得了高铬铸铁涂层和316L不锈钢涂层,采用维氏显微硬度计、图像分析软件、台式扫描电子显微镜及热场发射扫描电子显微镜分别对显微硬度、孔隙率、涂层厚度及结构进行了测试和分析。采用球-盘式往复摩擦试验机对比研究了两种涂层与典型缸套材料HT200灰铸铁在大气环境、纯发动机油润滑环境和模拟发动机腐蚀性油润滑环境下的摩擦学性能。结果表明:高铬铸铁涂层在腐蚀性发动机油环境中表现出好的摩擦磨损性能。     

Tribological evaluation of diamond coating on pure titanium in comparison with plasma nitrided titanium and uncoated titanium

Titanium alloys are characterized by poor tribological properties, and the traditional use of titanium alloys has been restricted to nontribological applications. The deposition of a well adherent diamond coating is a promising way to solve this problem. In this study, the tribological properties of diamond-coated titanium were studied using a pin-on-disk tribometer, and the results were compared with those of pure titanium and plasma nitrided titanium. The tribological behavior of pure titanium was characterized by high coefficient of friction and rapid wear of materials. Plasma nitriding improved the wear resistance only under low normal load; however, this hardened layer was not efficient in improving the wear resistance and the friction properties under high normal load. Diamond coating on pure titanium improved the wear resistance of titanium significantly. Surface profilometry measurement indicated that little or no wear of the diamond coating occurred under the test conditions loads. The roughness of the diamond coating was critical because it controlled the amount of abrasive damage on the counterface. Reducing the surface roughness by polishing led to the reductions in both the friction and wear of the counterface.     

Tribological behavior and mechanism of NiCrBSi–Y2O3 composite coatings

The NiCrBSi–Y₂O₃ composite coatings were prepared on the surface of 45 carbon steel by plasma spray, the microstructure and tribological properties of the coatings were investigated. The results show that the NiCrBSi–Y₂O₃ composite coatings are mainly composed of γ-Ni, CrB, Cr₇C₃ and Y₂O₃. With addition of Y₂O₃, hard phases such as CrB, Cr₇C₃ emerge in composite coating, and the density of the composite coatings also increases. The NiCrBSi–0.5Y₂O₃ composite coating presents excellent tribological properties. Its friction coefficient is 0.175, which is about 37% of that of the pure NiCrBSi coating. The mass wear loss is 1.2 mg, which is reduced by 43% compared with the pure NiCrBSi coating. When the loads are 6–10 N, the NiCrBSi–0.5Y₂O₃ composite coating suffers from slight wear and the wear mechanisms are mainly adhesive wear accompany with slight micro-cutting wear and micro-fracture wear. As the load increases to 12 N, the wear mechanisms are adhesive wear and severe micro-cutting wear.     

Improvement of the oxidation and wear resistance of pure Ti by laser cladding at elevated temperature

NiCrBSi and NiCrBSi/WC-Ni composite coatings were produced on pure Ti substrates by the laser cladding technology. Thermal gravimetric (TG) analysis was used to evaluate the high temperature oxidation resistance of the laser cladding coatings. The friction and wear behavior was tested through sliding against the Si₃N₄ ball at elevated temperatures of 300 °C and 500 °C. Besides, the morphologies of the worn surfaces and wear debris were analyzed by scanning electron microscopy (SEM) and three dimensional non-contact surface mapping. The results show that the microhardness, high temperature oxidation resistance and high temperature wear resistance of the pure Ti substrates are greatly increased. For the pure Ti substrate, the wear behavior is dominated by adhesive wear, abrasive wear and severe plastic deformation, while both laser cladding coatings, involving only mild abrasive and fatigue wear, are able to prevent the substrates from severe adhesion and abrasive wear. In particular, the laser cladding NiCrBSi/WC-Ni composite coating shows better high temperature wear resistance than the NiCrBSi coating, which is due to the formation of a hard WC phase in the composite coating.     

热处理对钽强化激光熔覆NiCrBSi涂层的影响

通过在激光熔覆NiCrBSi涂层(Ni60)中添加钽(Ta)元素来提高900℃热处理后涂层的耐磨性.研究了900℃热处理对激光熔覆NiCrBSi和钽强化NiCrBSi复合涂层显微组织、硬度以及耐磨性能的影响.利用带能谱仪的扫描电镜和衍射仪分析涂层的显微组织和物相.通过盘-销实验评价涂层的耐磨性.结果表明:经过900℃热处理后涂层中的M7C3和M23C6发生了分解,钽强化复合涂层和纯NiCrBSi涂层中的硬度都有所下降,但由于复合涂层中原位生成的TaC未发生分解,使得其硬度和耐磨性都高于纯NiCrBSi涂层.     

钛合金叶尖保护涂层的制备与表征

通过对TC4钛合金基体进行表面活化处理,并采用复合电镀技术,在钛合金基体上制备了结合力良好的Ni-c BN复合镀层。研制的复合镀层能够减少航空发动机钛合金叶片叶尖的摩擦磨损、杜绝"钛火"事故。进行了镀层的高温摩擦磨损试验以及与镍基封严涂层的磨削试验,利用扫描电子显微镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)等对涂层性能进行表征。结果表明:采用的钛合金基体表面活化处理技术,可保证复合镀层具有良好的结合力;同时,研制的Ni-c BN复合镀层对封严涂层具有良好的磨削能力和较低的摩擦系数,可以有效保护钛合金叶尖。     

钛合金表面激光熔覆陶瓷涂层的研究进展

针对钛合金在实际应用过程中存在硬度低、耐磨性差、高温易氧化以及生物活性低等问题,国内外学者利用陶瓷材料较高的硬度、优异的耐磨性和高温抗氧化性能的特点,以及激光熔覆技术可以实现涂层与基材的冶金结合,较高的冷却速率使涂层内部晶粒得到细化的优势,开展了钛合金表面激光熔覆陶瓷涂层的广泛研究。首先简要概括了钛合金表面激光熔覆陶瓷材料的特点,介绍了在激光熔覆过程中常见的陶瓷材料以及所具备的特殊性能。从陶瓷涂层制备方式和陶瓷材料体现的功能两个方面,综述了国内外的研究特点、现状和进展。对比分析了激光制备纯陶瓷涂层、激光制备陶瓷与金属合金复合涂层、激光原位合成陶瓷复合涂层、激光制备陶瓷梯度涂层的优缺点。介绍了在钛合金表面激光熔覆耐磨涂层、高温抗氧化涂层、耐蚀涂层和生物涂层的进展,分析了陶瓷材料在提高相关性能时所发挥的作用。最后针对钛合金表面激光熔覆陶瓷材料存在的问题,对钛合金表面激光熔覆陶瓷涂层未来的发展趋势进行了讨论与展望。     

Sliding wear characteristics of solid lubricant coating on titanium alloy surface modified by laser texturing and ternary hard coatings

Titanium alloys are poor in wear resistance and it is not suitable under sliding conditions even with lubrication because of its severe adhesive wear tendency. The surface modifications through texturing and surface coating were used to enhance the surface properties of the titanium alloy substrate. Hard and wear resistant coatings such as TiAlN and AlCrN were applied over textured titanium alloy surfaces with chromium as interlayer. To improve the friction and wear resisting performance of hard coatings further, solid lubricant, molybdenum disulphide (MoS2), was deposited on dimples made over hard coatings. Unidirectional sliding wear tests were performed with pin on disc contact geometry, to evaluate the tribological performance of coated substrates. The tests were performed under three different normal loads for a period of 40 min at sliding velocity of 2 m/s. The tribological behaviours of multi-layer coatings such as coating structure, friction coefficient and specific wear rate were investigated and analyzed. The lower friction coefficient of approximately 0.1 was found at the early sliding stage, which reduces the material transfer and increases the wear life. Although, the friction coefficient increased to high values after MoS₂ coating was partially removed, substrate was still protected against wear by underlying hard composite layer.