LaF_3对激光原位合成TiC/Ni涂层耐蚀性的影响

以Ni60、Ti、石墨、Mo及La_3为原料,在闸板表面激光熔覆原位合成了TiC/Ni复合涂层.利用SEM、电化学腐蚀系统对涂层组织和耐蚀性能进行分析.结果表明,未添加LaF_3,和添加3%LaF_3的熔覆层中存在异质相.自腐蚀电流升高,腐蚀电位降低,耐蚀性下降;添加2%LaF_3的熔覆层中异质相消失,腐蚀电流密度降低,腐蚀电位升高,钝化区宽度增加,耐蚀性提高.     

激光原位合成TiC-Ni-Mo涂层界面组织与磨损性能

利用激光熔覆原位合成了TiC-Ni-Mo复合涂层,借助于EPMA,TEM分析以及磨损试验,研究了TiC-Ni-Mo涂层的界面组织与磨损性能.结果表明,在涂层中添加5%Mo,可以细化TiC晶粒,改善涂层组织的均匀性,提高涂层硬度和耐磨性,降低摩擦系数,Tic/Ni界面存在如下位向关系:(001)TiC//(111)γ-Ni.添加10%Mo,涂层硬度和耐磨性下降.TiC颗粒中存在大量呈一定方向分布的位错,γ-Ni相内部的位错杂乱分布;熔覆层的耐磨机制为增强相的抗磨作用,磨损形貌为短而浅的犁沟.     

激光熔覆原位合成TiC增强Fe基复合层组织研究

在45钢表面激光熔覆原位合成TiC颗粒增强Fe基复合涂层。利用扫描电镜、能谱仪和X射线衍射仪对TiC/Fe复合涂层的显微组织、合金成分以及物相进行分析,测试了熔覆层的显微硬度和耐磨性能。结果表明,当(Ti+C)的含量在复合粉末中的比例达到15%时,熔覆层生成了少量的TiC颗粒,其形状呈多面体和花瓣状,直径为1~5μm,长度为3~5μm,TiC增强相组织中含有Fe、Cr等元素,而不是单纯的二元碳化物。由于少量TiC颗粒的团聚现象,造成TiC激光熔覆层的显微硬度低于Fe基熔覆层,但TiC激光熔覆层磨损性能优于Fe基熔覆层。     

激光熔覆原位自生TiC颗粒增强Ni基复合涂层的组织与性能

采用激光熔覆技术在H13钢表面制备出原位自生TiC颗粒增强Ni基复合涂层,利用扫描电镜、能谱仪和X射线衍射仪对熔覆层组织、成分和物相进行了分析,并测试了熔覆层显微硬度和耐磨性能.结果表明,激光熔覆层与基体呈良好的冶金结合,涂层中无裂纹、气孔等缺陷.涂层组织由γ-Ni、Cr7C3和TiC等相组成,原位自生TiC颗粒多呈菱形,尺寸在1～3μm之间,涂层显微硬度(800～1000 HV0.2)明显高于基体的显微硬度(300 HV0.2).激光熔覆层中存在颗粒强化和细晶强化等多种强化作用,显著提高了H13钢的耐磨性能.     

Ni对钛合金表面稀土激光熔覆层中TiC生长的影响

利用同步送粉激光熔覆技术,在Ti811钛合金表面激光熔覆原位合成了TiC和TiB_2颗粒增强镍基复合涂层。利用X射线衍射仪(XRD)、扫描电镜(SEM)、能谱分析仪(EDS)分析了熔覆层的显微组织和物相组成,利用显微硬度计测试了熔覆层的显微硬度。试验结果表明,激光熔覆涂层与基体呈冶金结合,涂层的物相主要由α-Ti、TiC、Ti_2Ni和TiB_2组成,其中TiC呈树枝晶状和花瓣状,TiB_2呈长条状。平衡状态下TiC以正八面体晶体结构存在,但熔体中存在的Ni元素会影响TiC平衡状态,使其最终呈现六边形形貌。稀土氧化物Y_2O_3的加入有利于促进晶粒细化,提高熔覆层组织均匀性及表面硬度。熔覆层的显微硬度显著提高,最高硬度为900HV0.5左右,约为基底硬度的2.25倍。     

TiC含量对TC4合金激光熔覆层组织和性能的影响

采用激光熔覆工艺在TC4钛合金基体表面制备了添加不同质量分数(0%、2%、4%、6%)TiC的Ni60A复合熔覆层,通过光学显微镜、显微硬度计、X射线衍射仪、摩擦磨损机分析了不同TiC含量对熔覆层组织及性能的影响。结果表明:未添加TiC的熔覆层组织以树枝晶为主,添加TiC后出现了花瓣状物相;XRD分析发现熔覆层中出现了AlCCr₂、Al_0.24B_0.01Ni_0.75等硬质增强相,这些能够显著提高熔覆层的硬度。显微硬度及摩擦磨损试验结果表明,添加TiC的熔覆层平均硬度均较基体硬度有大幅提高,摩擦因数显著降低,且随TiC含量的增加,熔覆层硬度先增加后降低,摩擦因数先降低后增加,4%TiC熔覆层的硬度最大,相比基体提高了213.3%,摩擦因数最小,为0.309 774。     

等离子熔覆TiC/Fe基熔覆层显微组织及碳化物演变机理分析

目的 为了提高3Cr13马氏体不锈钢的硬度和耐磨性,在其表面制备TiC/Fe基熔覆层,分析熔覆层组织的均匀性及碳化物类型,探究碳化物演变机理和对熔覆层硬度的影响规律。方法 采用等离子同步送粉熔覆,在3Cr13不锈钢基材上熔覆球形TiC/Fe基熔覆层。利用扫描电子显微镜、X射线衍射、能谱仪分析熔覆层微观形貌特征、相组成以及析出相的元素分布规律,利用显微硬度计测量熔覆层的硬度。结果 随着TiC添加量的增加,熔覆层中的Ti和C元素含量也增加,说明有部分TiC熔解。未添加TiC的熔覆层组织主要是Fe-Cr固溶体和(Fe、Cr)7C3,TiC/Fe基熔覆层的为Fe-Cr固溶体和TiC、(Fe、Cr)3C2、(Fe、Cr)7C3。两种熔覆层中的析出相主要以(Fe、Cr)7C3为主,但在TiC/Fe基熔覆层中还存在其熔解后重新析出的TiC及过渡相(Fe、Cr)3C2。TiC添加量增加,熔覆层显微硬度也增加。结论 TiC/Fe基熔覆层中的第二相除(Fe、Cr)7C3,还有原始TiC、析出的TiC和(Fe、Cr)3C2。在研究范围内,随着TiC添加量增加,熔覆层中熔解的TiC量也增加。析出的TiC可以作为(Fe3Cr4)C3的有效形核质点,促进(Fe3Cr4)C3的形成,形成过程是(Fe、Cr)3C2以析出的TiC为形核核心形核长大,随后相变为更加稳定的(Fe、Cr)7C3,在快速冷却过程中有未转变完的(Fe、Cr)3C2保留下来。熔覆层中的原始TiC、析出的TiC、生成的(Fe、Cr)7C3和(Fe、Cr)3C2作为硬质相提高了熔覆层的硬度。     

氩弧熔覆 TiC 颗粒增强 Fe 基涂层组织性能研究

目的研究氩弧熔覆条件下TiC颗粒增强Fe基涂层的组织和性能。方法在Fe45自熔性合金粉末中添加TiC颗粒,利用氩弧熔覆技术在Q235钢基材表面制备出含TiC颗粒增强的Fe基合金复合涂层,并对熔覆层的显微组织结构、硬度分布及耐磨性能进行分析研究。结果复合涂层是由(Fe,Ni)形成的枝晶和枝晶间的(Fe,Cr)23(C,B)6,Fe3(C,B)共晶组织以及TiC增强颗粒组成,TiC颗粒细小弥散分布在基体金属内,部分TiC颗粒聚集生长为棒状、十字状和放射状。结论熔覆层的显微硬度最高可达980HV,较Q235钢提高了4倍,耐磨性提高了约11倍。     

激光熔覆TiC颗粒增强Fe基梯度涂层的耐磨性能

采用激光熔覆的方法将TiC颗粒增强铁基粉末熔覆在40Cr钢基体上制备高硬度耐磨梯度陶瓷涂层。利用扫描电镜（SEM）、能谱仪（EDS）、X射线衍射仪（XRD）、显微硬度计、摩擦磨损试验机对熔覆层的微观组织、物相、硬度及耐磨性进行研究。结果表明：熔覆层物相主要为奥氏体相、TiC强化相,并有少量铁素体相,激光熔覆TiC颗粒增强粉末制备的金属陶瓷涂层组织致密、物相与粉末组成基本一致;TiC 强化相在熔池底部到顶部呈梯度分布,熔池中TiC强化相部分溶解、尺寸减小,部分受激光热作用长大呈四方形、雪花状、鱼骨状,TiC相在熔池底部呈现3种生长方式,且TiC增强相分布较少,熔池中部TiC增强相逐渐增多,熔池上部TiC增强相出现富集并桥接生长;熔覆层维氏硬度HV高达19 602.94 MPa,同等条件下,涂层的摩擦磨损深度为基体的1/5,显著提高了基体的耐磨性。     

氩弧熔覆制备WC颗粒增强复合涂层及其组织性能研究

采用氩弧熔覆技术,在45号钢表面制备出WC颗粒增强的耐磨复合涂层.通过光学显微镜、SEM、XRD和EDS分析了氩弧熔覆层的显微组织和相组成,并测试了熔覆层的显微硬度和耐磨性能.结果显示,熔覆层枝晶中弥散分布WC和W2C硬质相颗粒,出现Fe(W)固溶体和M6C型化合物,显微硬度(HV0.1)最高可达970,使基体45号钢的耐磨性能有较大提高.     

Microstructure and properties of WC reinforced Ni-based composite coatings with Y2O3 addition on titanium alloy by laser cladding

ABSTRACT

In this study, WC reinforced Ni-based composite coatings with Y₂O₃ addition were deposited on Ti-6Al-4V titanium substrate by laser cladding. The phases, microstructure, microhardness and wear resistance of the composite coatings were studied by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, microhardness tester and wear tester. The results showed that good metallurgical bonding was achieved between the composite coatings and substrate. The phases mainly were γ-Ni, TiC, TiB₂, Ni₃B, M₂₃C₆ and WC. Most of the WC was dissolved in small pieces of WC during the laser cladding process. The microhardness of the composite coatings was about 3 times that of the titanium substrate and the wear resistance of the composite coatings had a significant increase.     

激光原位合成TiB2-TiC颗粒增强铁基涂层

采用B4C,TiO2,石墨以及铁基粉末为激光熔覆材料,利用激光多道搭接熔覆技术在碳钢基体上制备TiB2-TiC颗粒增强铁基复合涂层．利用XRD,SEM对涂层的相结构和显微组织进行了研究．采用显微硬度计和滑动磨损试验机分别测试了涂层的硬度和耐磨性能．结果表明,激光熔覆过程B4C,TiO2和石墨反应生成了TiB2和TiC颗粒,并均匀分布在基体中．随着激光功率密度增加,涂层中TiC含量减少,甚至出现FeB脆性相．TiB2-TiC颗粒增强的涂层其硬度和耐磨性能优于基材45钢．     

稀土对电沉积镍基合金镀层组织和耐蚀性的影响

针对提高镍基合金镀层性能问题,采用单脉冲电沉积法制备镍基合金镀层,并用扫描电镜、电化学和失重法研究了镀液中添加稀土元素对镍基合金镀层的组织和耐蚀性的影响。结果表明：镀液中添加适量的稀土能细化镍基合金镀层组织,使镀层表面平整致密,有效地提高镀层的耐蚀性能。     

Wear and corrosion resistance of AZ91 magnesium alloy coated by pulsed current electrodeposited Ni–Al2O3 nanocomposite

In this work, Ni and Ni–Al₂O₃ nanocomposite coatings were applied on AZ91 magnesium alloy using a pulse plating process and the corrosion resistance of coated samples was evaluated by means of the potentiodynamic polarisation method in 3.5?wt-% NaCl solution. Field emission scanning electron microscopy was employed to identify microstructure and morphology of the coatings. Vickers microhardness and pin-on-disc wear tests were also used to investigate mechanical properties of the coatings. The polarisation test revealed that the pure Ni coating on AZ91 along with the presence of nanoparticles were key factors leading to a reduction in the corrosion current density and the improvement of corrosion resistance so that the corrosion current density of 210.45?µA?cm^?2 for the substrate (AZ91) decreases to 31.92 and 1.54?µA?cm^?2 by applying pure Ni and Ni–Al₂O₃ nanocomposite coatings, respectively. Furthermore, Ni–Al₂O₃ nanocomposite coating increased the microhardness and wear resistance compared to the substrate up to 435 and 340%, respectively.     

等离子熔覆TiC/Fe-Cr金属陶瓷复合涂层

以钛铁粉、高碳铬铁粉、硼铁粉、硅铁粉等为原料,利用等离子熔覆技术在Q235钢表面原位反应合成了与基材冶金结合Ti/Fe-Cr金属陶瓷复合涂层.利用SEM,XRD和EDS等分析了涂层的显微组织,并在室温于滑动磨损条件下测试了该涂层的耐磨性能.结果表明,涂层组织由TiC相、初生相Cr7C3、共晶(Cr,Fe)7C3和奥氏体...     

TC4钛合金表面激光熔覆掺Y2O3复合涂层的显微组织和性能

目的提高钛合金表面的耐磨性能。方法在TiB_2:TiC=1:3的粉末配比下,添加不同质量分数Y_2O_3稀土氧化物,制备成膏状混合粉末。采用5 k W横流CO_2激光器,在TC4钛合金表面激光熔覆掺Y_2O_3的TiB_2和TiC粉末,制备耐磨性复合涂层。通过扫描电子显微镜(SEM)、X射线能谱仪(EDS)、X射线衍射仪(XRD)对激光熔覆层的微观形貌和组织成分进行了分析;用显微维氏硬度计对熔覆层的显微硬度进行了测量;用万能摩擦磨损试验机对熔覆层的耐磨性能进行了测试。结果添加4%Y_2O_3后,熔覆层中部组织明显细化,结合区由致密组织结构转变为晶须网状结构;熔覆层的最高显微硬度为1404.6HV0.2,是基体的3.7倍;熔覆层的磨损量减少了66.67%,且其摩擦系数有明显的降低。结论添加4%Y_2O_3对TC4钛合金表面激光熔覆TiB/TiC复合熔覆层耐磨性能有显著的提高。     

Microstructure and Wear Performance of Arc Sprayed Fe-FeB-WC Coatings

Two Fe-FeB-WC coatings were deposited on the Q235 steel substrate by arc spraying. The microstructure and the abrasive wear performance of the coatings were characterized by x-ray diffraction (XRD) and scanning electron microscope (SEM). The wear mechanisms of the coatings were examined. It was found that Fe-Cr alloy and Fe₂B are present in the coating as the main phases. The results showed that adding hard particle powders could obviously increase the hardness and wear resistance of the coatings. The average microhardness of the coatings was about 870 to 920 HV_0.1. The coatings exhibited excellent abrasive wear resistance, being 3.3 to 4.8 times higher than that of arc sprayed 3Cr13 coating.     

Y2O3对原位自生TiC增强Ni基涂层组织和性能影响

采用氩弧熔覆的方法,以Ni60A自熔性合金粉末为粘结相,添加Ti粉、C粉和不同含量的稀土氧化物Y₂O₃,在16Mn钢基体上制备出TiC陶瓷颗粒增强金属基熔覆涂层. 运用XRD, SEM等手段对复合涂层的显微组织进行表征和分析,并对熔覆涂层的硬度及耐磨性进行了测试. 结果表明,适量添加Y₂O₃可以使涂层组织中枝晶的方向性减弱、同时细化涂层组织,使涂层组织更加均匀,涂层的硬度和耐磨性有显著提高. 添加2% Y₂O₃熔覆涂层的组织为最细,涂层具有较高的显微硬度和良好的耐磨性能.     

Corrosion and tribological behaviors of chromium oxide coatings prepared by the glow-discharge plasma technique

In order to improve the corrosion and tribological properties of steel, chromium oxide coatings were prepared by a new combined process, namely, chromizing and plasma oxidizing treatments using double glow plasma technology under various oxygen flow rates. The composition and microstructure of the coatings were analyzed respectively by means of X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The results indicated that the oxygen flow rates had a great effect on the surface structure of the prepared Cr₂O₃ coatings, and dense and smooth Cr₂O₃ coatings were prepared at the oxygen flow rate of 10 sccm. The Cr₂O₃ coatings exhibited the better corrosion resistance which was in good agreement with the results obtained by the microstructure studied. Further mechanical properties test showed that the Cr₂O₃ coatings with high hardness and elastic modulus adhered well to the steel substrates and displayed excellent wear resistance and low coefficient of friction under dry sliding wear test conditions. The wear mechanism was mostly dominated by the “soft abrasion”.     

TiC含量对激光选区熔化Inconel 625合金微观组织及表面摩擦磨损性能的影响

为了提高3D打印镍基高温合金强度、硬度及耐磨性能,使用激光选区熔化技术(Selective laser melting,SLM)制备添加不同质量分数TiC增强Inconel 625合金材料,并对比添加不同质量分数TiC(4 wt.%和8 wt.%)所制备的SLM TiC/Inconel 625试样的摩擦磨损性能。结合X射线衍射仪(XRD),金相显微镜(OM),扫描电子显微镜(SEM)及能谱分析(EDS)等材料表征手段对TiC/Inconel 625试样的物相分布,微观组织结构及磨损前后的元素分布进行对比分析。结果表明,随着TiC含量的增高,SLM TiC/Inconel 625硬度从325 HV_(0.2)(不含TiC)升高到了587 HV_(0.2)(SLM 8 wt.%TiC/Inconel 625),磨损率也由22.4×10~(-5)mm~3/(N·m)下降为9.8×10~(-5)mm~3/(N·m)。其中,平均摩擦磨损系数最小的为SLM 4 wt.%Ti C/Inconel 625 (COF=0.47)。综合对比可以发现通过添加适量的TiC颗粒可以有限改善SLM Inconel 625的硬度及耐磨损性能。