TC1合金表面电火花沉积WC-8Co涂层界面行为

钛合金在航空、航天工业得到了广泛应用。但其耐磨性差，对磨面容易产生粘结及对微动磨损敏感等缺点，限制其应用领域的进一步扩大，实践证明，采用电火花强化技术在TCl合金表面制造WC-8Co强化层，可以有效提高TCl基体表面耐磨性能。作者研究了WC-8Co强化层的表面状态、界面行为以及相结构组成，认为TCl合金表面强化高熔点的WC-8Co材料，厚度可大于50μm；强化层与基体之间存在过渡区；强化层表面由TiC、W2C和少量W组成；强化层截面的显微硬度是基体的3倍以上。     

硅电极电火花放电的表面改性技术研究

采用单晶硅材料作工具电极,选择合适的脉冲放电参数对碳素工具钢进行电火花表面强化,在工件表面上形成一层硅及硅的化合物.研究结果表明,表面硅化处理后的工件表面硬度、耐磨性和耐腐蚀性均明显提高,可有效提高工件的性能和使用寿命.     

H13钢表面电火花沉积WC涂层

利用DZ-4000(Ⅲ)型电火花沉积/堆焊机,以WC为电极材料,采用氩气为保护气对H13钢基体进行了电火花表面强化.利用扫描电镜、能谱分析仪、X射线衍射仪和显微硬度计等对沉积层的成分、组织、硬度和表面粗糙度进行了研究.结果表明,利用电火花沉积工艺可获得组织均匀、致密,且与基体呈冶金结合的沉积层,沉积层平均厚度约60μm.沉积层主要由Fe3W3C、(CrFe)7C3和W2C等相组成.沉积层的平均显微硬度为1321.4 HV0.05,约为基体硬度的3倍.     

钛合金表面电火花沉积WC涂层的研究

以WC为电极,采用不同的电火花强化工艺,在钛合金表面制备了强化涂层。为了比较不同工艺条件下获得涂层的组织结构,确定最佳的电火花沉积工艺,通过金相、SEM、EDS等试验方法对涂层的微观组织结构进行了研究。结果表明,仅改变电火花沉积参数对获得性能优良的沉积涂层效果不明显,当复合超声加工,并且达到一定频率范围时,可以明显改善涂层质量。所获涂层是由基体中Ti元素与WC电极发生反应生成的反应涂层,涂层的主要成分是TiC、W和W2C。     

轧辊表面电火花沉积涂层的耐磨性

采用电火花沉积工艺,用WC陶瓷硬质合金在铸钢轧辊表面制备了一层合金涂层。采用X射线衍射仪、扫描电镜、显微硬度计等对沉积层的相结构、显微组织、显微硬度及耐磨性能进行了分析。结果表明:沉积层主要由Co3W3C、Fe3W3C、W2C、Si2W等相组成;沉积层与基体呈冶金结合,细小的硬质相弥散分布于沉积层中;沉积层的平均硬度为1915 HV0.3,约是基体硬度(352 HV0.3)的5.4倍;其室温耐磨性能比基体提高了2.1倍,高温耐磨性能比基体提高了1.9倍。室温下沉积层的主要磨损机理为磨粒磨损;高温下沉积层的主要磨损机理为粘着磨损、氧化磨损和疲劳磨损。     

钛合金表面反应电火花沉积TiN/Ti复合涂层

利用自制的电火花沉积充气密闭式保护装置和DZ-1400型电火花沉积/堆焊机,以工业纯钛TA2为电极,以工业纯氮为保护气和反应气,在TC4钛合金表面上反应电火花沉积制备了TiN/Ti复合涂层.利用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、X射线光电子仪(XPS)分析了涂层的组织、物相和元素组成,利用显微硬度计测定了涂层的显微硬度,利用自制磨损试验装置对比涂层与淬火W18Cr4V高速钢的磨损性能.结果表明,涂层与基体形成良好的冶金结合,涂层主要由钛和反应合成的TiN组成,涂层的平均显微硬度可达1 388 HV0.1,是基体硬度的6倍以上,涂层具有较好的耐磨性.

Abstract：

TiN/Ti composite coating was deposited on TC4 titanium alloy substrate with the self-made special gas-filled-closed electric-spark deposition device and electric-spark deposition machine modeled DZ-1400, the industry pure titanium (TA2) was used as electrode and the industry pure nitrogen gas as shielding and reacting atmosphere. The microstructures, interfacial behavior, phase and element in the coatings were investigated by scanning electronic microscope, X-ray diffraction and X-ray photo spectrum. The microhardness of coatings was tested and its wear-resistance property was tested by the self-made abrasion machine and compared with Wi8Cr4V rapid steel treated by quenching. The results show that an excellent bonding between the coating and substrate is ensured by the strong metallurgical interface. The coatings are mainly composed of Ti and synthesized TiN. The highest microhardness of coating reaches to 1 388 HV0. 1, which is six times higher than that of the substrates. Wear resistance of the coatings is excellent.     

钛合金表面电火花沉积强化研究现状

介绍了电火花表面沉积工艺的基本原理和技术特点，以及国内外电火花沉积技术在钛合金表面强化领域的研究现状。在钛合金表面进行电火花沉积，可得到具有高硬、耐磨、耐高温氧化、低摩擦系数的特殊表面涂层。虽然电火花表面强化技术具有特殊的强化效果，但存在着电火花强化层的表面粗糙度不容易控制、生产效率低、强化工艺不稳定的缺点。因此，今后要深入研究电火花放电机理，进一步提高强化效率，研究不同电极、基体材料的强化工艺。     

电火花沉积表面处理技术的应用进展

电火花沉积是一种具有独特技术优势,节能、省材、环保的新兴材料表面处理技术,不仅广泛应用于工具、模具、刃具、矿山、冶金、汽车、医用器材等一般工业领域,还可以应用到核反应堆、直升机和战机引擎等军工零部件的表面处理.介绍了电火花沉积技术的特点,通过典型事例介绍了该技术在耐磨损、耐腐蚀、抗氧化、表面修复与改性方面的应用,分析了电火花沉积技术的应用现状,指出了国内在电火花应用和研究方面与国外的差距,并提出了促进我国表面技术研究者积极研究并大力推广应用的建议.     

超声波与电火花表面复合强化Ti17合金的疲劳性能

将Ti17合金经过电火花处理(EST)后再进行超声波表面处理以期提高疲劳寿命。通过扫描电子显微镜观察表面形貌及强化层结构,经X射线衍射分析表面残余应力,采用HT-100高温疲劳试验机测试350 ℃拉-拉疲劳寿命。结果表明,经过超声波表面处理后,试样表面粗糙度及表面残余应力降低,复合强化后试样的疲劳寿命是仅经过EST处理的两倍。经过硬质合金YG8电极EST以及超声波复合处理的试样疲劳寿命最长     

钛合金表面反应电火花沉积Ti(CN)涂层研究

利用自行研制的反应电火花沉积系统,以石墨为电极,以工业氮气为保护气,在TCA钛合金基体上原位反应合成了Ti(CN)金属基陶瓷复合涂层.利用SEM分析了涂层单沉积点表面形貌和组织结构,利用X射线仪测定了涂层的物相组成,利用XPS分析了涂层表面元素组成,利用SEM和AES分析了涂层断面形貌、结合状态和元素组成;结果表明,涂层表面单沉积点形貌呈不规则的"溅射状",涂层主要由呈球块状晶和枝晶的TiC0.51N0.12相、Ti080V0.20 相和C相组成且晶块平均尺寸为626nm,涂层与基体的结合致密,呈冶金结合.     

电火花沉积法在铜电极表面制备TiB2/Ni涂层

为了提高镀锌钢板用点焊电极的使用寿命,在铜电极表面涂覆过渡层Ni后沉积了TiB2涂层。通过SEM和XRD分析了Ni和TiB2涂层的物相和微观结构,并测试了其显微硬度。结果表明：由于材料具有良好的塑性,预涂覆的Ni涂层结构致密无裂纹,与基体Cu无分层;而TiB2涂层内存在裂纹和孔洞。通过过渡层Ni将TiB2涂层和基体Cu粘结起来,获得了较理想的涂层。随着电火花放电电容和电压的增加,TiB2的氧化程度增强,Cu和Ni大量扩散进入涂层表面,使TiB2/Ni涂层的硬度降低。由于TiB2良好的导电和导热性能及高的硬度,TiB2/Ni涂层电极在点焊时的塑性变形降低,寿命比无涂层电极和TiC涂层电极得到了明显提高。     

Research on depositing Ni45 alloy on titanium alloy surface by electrospark deposition

Taking Ni45 bar as electrode, a strengthened layer of thickness up to 50 μm was built up on BT20 titanium alloy matrix by means of electrospark deposition. Results of phase analysis by using of X-ray diffraction confirmed that the deposition layer was composed mostly of three phases, NiTi, NiTi2 and Ti. The surface microhardness of the deposition layer was up to 910 HV0.05, about 2.7 times as high as that of the matrix. The hardness at the cross-section of the entire deposition layer showed a gradient distribution. The effects of capacitance and deposition time on thickness of deposition layer were also studied, and results showed that with relatively low capacity and short deposition time the deposition layer without cracks can be obtained.     

铜电极表面电火花沉积ZrB_2-TiB_2复相涂层

采用粉末冶金法制备Zr B2-Ti B2复相材料熔敷棒,并通过电火花沉积工艺在铜电极表面制备Zr B2-Ti B2复相涂层。通过扫描电镜结合能谱分析研究了涂层的显微结构和元素分布,利用X射线衍射和显微硬度测试对涂层的物相组成与显微硬度进行检测。结果表明:直接熔敷Zr B2-Ti B2复相涂层致密性较差,且存在较多裂纹,与基体有明显分层,涂层物相为Cu、Zr B2和Ti B2;在预沉积Ni层(Ni层)上后沉积Zr B2-Ti B2,所得的多层涂层具有较好的致密性,且涂层与基体间无分层;中间层有Ti、Zr、Cu元素的扩散,说明涂层与基体为冶金结合;Zr B2-Ti B2复相涂层硬度为900 HV0.05稍高于多层涂层硬度(800 HV0.05)。     

点焊电极表面电火花沉积TiB_2涂层的特征

在CuCrZr电极表面通过电火花振动沉积制备了TiB_2功能涂层,测试了功能涂层的显微形貌、物相、硬度以及界面元素分布.试验表明,TiB_2涂层电极具有典型的电火花涂层结构,存在明显的元素互扩散,表明功能层与基体之间为冶金结合.但TiB_2涂层结构不致密,存在裂纹和孔洞,硬度较低.随着电火花电容和电压的增加.涂层的硬度降低.元素扩散和涂层氧化的加剧,是导致涂层硬度降低的主要原因.由于基体Cu的气化、脆性剥落和熔敷棒的切削作用,沉积TiB_2后基体质量反而降低.高电压下电火花沉积以及预涂敷Ni,都会导致基体质量降低更多.     

Mass loss of copper alloy electrode during TiB2 coating by electrospark deposition

Titanium diboride was deposited on the surface of spot-welding electrodes for zinc coated steel sheets due to its high electrical and thermal conductivity and potential to prolong the lifespan of the electrodes, and mass of the electrodes was measured after every 30 s during depositing. The results showed that the as-deposited electrodes are losing their mass during the process, which is completely different from the deposition of TiC. Evaporation of copper and oxidation of TiB₂ at high temperature generated by electrosparking play the most important roles in the mass loss. Cutting and flaking of the brittle coating also contribute to the mass loss. The cracks within the coating are channels for the leakage of the evaporated substrate material. The mass of the electrodes decreases as the pulse energy increases with the voltage increasing. Pre-coated nickel contributes to the mass loss of the electrodes too.     

钛合金表面电火花沉积WC电极的粘连行为分析

电火花沉积工艺具有热输入小,工件变形小,操作简单方便,适于现场操作等特点,在航空、航天、能源、核工业、医疗机械等各个领域都得到了广泛应用.针对目前关于电火花表面沉积的许多理论问题还不是很清楚这一情况,研究了在TC1合金基体上采用WC电极沉积时的WC电极的表面粘连现象,以及沉积时间对电极粘连程度的影响.分析表明,粘连在阳极表面的合金化金属层是多层结构,这是在电火花强化过程中,通过旋转电极与基体之间间断的或多次的"阳极粘连"后产生的.电极粘连程度随时间增加而加重,该层由Ti、W、C、Al等元素组成,该层中发生了冶金反应,生成了TiC.     

Microstructure and cavitation erosion characteristics of Al-Si alloy coating prepared by electrospark deposition

With a high-power electrospark deposition (ESD) processing unit, an Al-Si coating was prepared on ZL101 aluminum alloy substrate. The Al-Si coating was composed of many thin deposited layers with the thickness of 30-40 μm and showed peculiar microstructural characteristics. The eutectic Si phase, which was homogenously distributed in the coating, existed in the form of latticed morphology with characteristics of being composed of many fine (~ 50 nm size) spherical Si particles. Hardness tests showed that the microhardness of the coating was in the range of 100-110 HV with a small fluctuation, which implied that the deposited coating possess a uniform strength through the whole coating. After 4 hours' cavitation erosion tests, the cumulative volume loss of Al-Si coating (9.03 mm³) was only 31.5% of the substrate (28.66 mm³), which indicated that the Al-Si coating possessed better cavitation erosion resistance than ZL101 substrate. The excellent performance of Al-Si coating was mainly attributed to the peculiar microstructure and the formation of fine spherical Si particles.     

铝合金电火花沉积层的组织和抗空蚀性能

为了研究铝合金电火花沉积(ESD)的典型组织特征与抗空蚀修复应用的可行性,在ZL101铝合金表面制备了纯Al和Al-Si两种铝基合金ESD沉积涂层,并对所获涂层的典型显微组织和抗空蚀性能进行了研究.结果表明,两种沉积涂层均表现为典型的多层结构.纯Al涂层以α相为主,显微硬度仅为约50 HV,内部缺陷较多.Al-Si涂层内缺陷则较少,Si相呈均匀的枝蔓状分布,其显微硬度较纯铝涂层高约75％.沉积材料中Si元素的加入能够改善沉积微过程中熔融液滴的流动性,从而减少缺陷的产生.4h空蚀测试表明:纯铝涂层的累积质量损失为137.8 mg,约为基体的189％,抗空蚀性能较差;而Al-Si沉积涂层则较好,累积质量损失仅约为基体的32％(23.6 mg).分析认为,更好的子层间结合质量和高强度枝蔓状Si相的均匀分布是Al-Si沉积涂层拥有较好抗空蚀性能的主要原因.