Ti-6Al-2Zr-1Mo-3Nb合金微弧氧化陶瓷膜的结构与性能

利用微弧氧化技术,在Ti-6Al-2Zr-1Mo-3Nb合金表面制备陶瓷涂层。用扫描电镜和X射线衍射仪观察并分析陶瓷膜层的组织形貌和相结构,用电子万能材料试验机和数字万用表研究膜层的结合强度和绝缘性,并用MMS-1G高温高速销盘摩擦磨损试验机和YWX/Q-750盐雾试验机考察涂层的摩擦性能和耐腐蚀性能。结果表明:陶瓷层主要由金红石TiO2相和锐钛矿TiO2相构成,膜基结合强度达到30MPa以上,膜层绝缘性和耐腐蚀性良好,耐磨性得到明显改善,涂层的磨损机制表现为轻微的磨粒磨损与粘着磨损。     

Abrasive wear characteristics and mechanisms of Al2O3／PA1010 composite coatings

The abrasive wear characteristics of Al2O3/PA1010 composite coatings on the surface of quenched and low-temperature temper steel 45 were tested on the tumplate abrasive wear testing machine and the same uncoated steel 45 was used as a reference material. Experimental results showed that the abrasive wear resistance of Al2O3/PA 1010 composite coatings has a good linear relationship with the volume fraction of Al2O3 particles in Al2O3/PA1010 composite coatings, and the linear correlative coefficient is 0.979. Under the experimental conditions, the size of Al2O3 particles (40.5-161.0μm) has little influence on the abrasive wear resistance of Al2O3/PA1010 composite coatings. By treating the surface of Al2O3 parti-cles with a suitable bonding agent, the distribution of Al2O3 particles in matrix PA1010 is more homogeneous and the bonding state between Al2O3 particles and matrix PA1010 is better. Therefore, the Al2O3 particles in Al2O3/PA1010 compos-ite coatings make the Al2O3/PA1010 composite coatings have better abrasive wear resistance than PA1010 coatings. The wear resistance of Al2O3/PA1010 composite coatings is about 45% compared with that of steel 45.     

稀土铈掺杂石墨烯对7050铝合金微弧氧化膜层结构与性能的影响

采用微弧氧化(MAO)技术,以硅酸盐为主要电解液成分,通过加入稀土元素铈以及石墨烯添加剂,在7050高强铝合金表面制备微弧氧化膜层。利用扫描电镜(SEM)、体视显微镜、X射线衍射仪(XRD)、摩擦磨损试验机以及电化学工作站研究微弧氧化陶瓷膜层的形貌、粗糙度、相组成和元素分布以及耐磨性和耐蚀性。结果表明:同时加入4 g/L CeO2和10 g/L的石墨烯制备的复合膜层表面微孔尺寸明显降低,结构致密,耐磨性较好,粗糙度最低(1516.03 nm),膜层主要由α-Al2O3和γ-Al2O3组成。且此时的复合膜层自腐蚀电位最大,自腐蚀电流最小,耐腐蚀性最佳。     

Preparation of ceramic coatings on inner surface of steel tubes using a combined technique of hot-dipping and plasma electrolytic oxidation

A new method for inner surface modification of steel tubes, named a combined technique of hot-dipping and plasma electrolytic oxidation (PEO) was proposed and demonstrated in this paper. In this work, metallurgically bonded ceramic coatings on inner surface of steel tubes were obtained using this method. In the combined process, aluminum coatings on steel were firstly prepared by the hot-dip process and then metallurgically bonded ceramic coatings were obtained on the aluminum coatings by PEO. The element distribution, phase composition and morphology of the aluminide layer and the ceramic coatings were characterized by SEM/EDX and XRD. The corrosion resistance of the ceramic coatings were also studied. The results show that, after hot-dip treatment, the coating layers consist of two layers, where Al, Fe_xAl _(1−x) were detected from external topcoat to the aluminide/steel substrate. Then after PEO process, uniform Al₂O₃ ceramic coatings have been deposited on inner surface of steel tubes. The ceramic coatings are mainly composed of -Al₂O₃ and γ-Al₂O₃ phase. The compound coatings show favorable corrosion resistance property. The investigations indicate that the combination of hot-dipping and plasma electrolytic oxidation proves a promising technique for inner surface modification of steel tubes for protective purposes.     

CrAISiN涂层与不同材料配副时的摩擦学特性

目的 研究CrAlSiN涂层分别与304不锈钢、TC4钛合金、Al2O3陶瓷和GCr15钢四种不同材料配副时的摩擦学特性.方法 采用阴极电弧离子镀技术在M35高速钢上制备了CrAlSiN涂层,采用扫描电镜(SEM)、显微硬度计、划痕仪、球-盘式摩擦磨损试验仪和3D轮廓仪分别测试了涂层的结构和性能.结果 CrAlSiN涂层与304不锈钢、TC4钛合金和GCr15钢配副时的磨损形式为粘着磨损和磨粒磨损,其中与亲和性高的304不锈钢、TC4钛合金粘着磨损严重.CrAlSiN涂层与不锈钢对磨时,摩擦系数最高,达到0.71;与GCr15钢对磨时,摩擦系数最低,但摩擦系数波动大;与钛合金对磨时,摩擦系数介于两者之间.CrAlSiN涂层与亲和性较差的Al2O3陶瓷之间的磨损形式为磨粒磨损,随着磨损的进行,摩擦系数逐渐降低.结论 CrAlSiN涂层与亲和性较高的材料对磨时,磨损形式为粘着磨损和磨粒磨损,与亲和性较差的Al2O3对磨时为磨粒磨损.     

纳米Cr2O3微粒对2024-T4微弧氧化膜结构及耐磨性能的影响

摘 要: 在含有不同浓度纳米Cr2O3微粒的硅酸盐体系电解液中对2024-T4铝合金进行微弧氧化处理,使用SEM观察陶瓷膜的表面形貌和截面形貌,使用EDS能谱仪分析膜层中各主要成分沿截面方向的分布,使用XRD分析陶瓷膜的相结构,使用纳米压痕硬度计测量陶瓷膜的硬度,使用粗糙度仪测量陶瓷膜的表面粗糙度,使用摩擦磨损试验机测量陶瓷膜的摩擦系数,使用激光共聚焦显微镜测量磨痕体积,评估磨损率,使用SEM观察磨痕形貌,结果表明：在电解液中加入纳米Cr2O3微粒后,制备的陶瓷膜中出现了Cr2O3相,电解液中纳米Cr2O3微粒浓度达到2.4g/L时,陶瓷膜的硬度最高,摩擦系数最小,磨损率最低,耐磨性最好。     

Evaluation of corrosion and wear resistance of hard cermet coatings sprayed by using an improved HVOF process

Research for alternatives of hard chrome plating has been widely carried out in the world. High-velocity oxygen-fuel (HVOF)-sprayed cermet coating is one of such alternative candidates. Depending on the cermet powder for spraying, however, sometimes the density of the sprayed coatings is not sufficient for desired corrosion resistance. A gas-shroud (GS) attachment for use with commercial HVOF, which is effective in suppressing oxidation of sprayed particles while raising the velocity of sprayed particles, has been developed. The GS-HVOF spray has been successfully applied to corrosion resistant alloys such as HastelloyC. In this study, a WC cermet system with corrosion and wear resistance was sprayed using a gas-shroud attachment. Porosity in the coatings was observed by the microscopic observation of cross sections. Corrosion and wear resistance was evaluated by alternating current corrosion monitoring in artificial seawater and abrasive wear-tester, respectively. Coatings deposited by the gas-shroud HVOF were superior in terms of both corrosion and wear resistance to coatings formed by the conventional HVOF. The density of the sprayed coatings was improved using the gas-shroud attachment, resulting in superior corrosion and wear resistance.     

Formation and structure of composite coating of HDA and micro-plasma oxidation on A3 steel

Composite coatings were obtained on A3 steel by hot dipping aluminum(HDA) at 720 ℃ for 6 min and micro-plasma oxidation(MPO) in alkali electrolyte. The surface morphology, element distribution and interface structure of composite coatings were studied by means of XRD, SEM and EDS. The results show that the composite coatings obtained through HDA/MPO on A3 steel consist of four layers. From the surface to the substrate, the layer is loose Al2O3 ceramic, compact Al2O3 ceramic, Al and FeAl intermetallic compound layer in turn. The adhesions among all the layers are strengthened because the ceramic layer formed at the Al surface originally, FeAl intermetallic compound layer and substrate are combined in metallurgical form through mutual diffusion during HDA process.Initial experiment results disclose that the anti-corrosion performance and wear resistance of composite coating are obviously improved through HDA/MPO treatment.     

含碳化物陶瓷粉芯丝材电弧喷涂层的结构和性能

分别将WC、TiC、Cr3C2等碳化物陶瓷粉末与304不锈钢带轧制成3种粉芯丝材,采用电弧喷涂技术在Q235钢基体上制备铁基复合涂层.利用光学显微镜、SEM、XRD对3种涂层的形貌、相组成和磨损表面进行分析,并用湿砂橡胶轮磨损试验机(MLS-225)测试了涂层的抗磨粒磨损性能.结果表明,碳化物陶瓷粉末的加入使涂层的硬度和耐磨性显著提高,涂层的平均显微硬度值高达1100～1200 HV0.1.在本试验条件下,铁基复合涂层的耐磨性比Q235钢高6～18倍.塑性微切削和脆性剥落为涂层的主要磨粒磨损形式.     

等离子喷涂纳米Al2O3/Ni复合涂层的组织和耐磨性能研究

将纳米Al2O3颗粒和镍基粉用湿法混合,采用等离子喷涂工艺制备了复合涂层。利用SEM和TEM分析了Al2O3复合涂层的表面形貌和微观组织,用磨粒磨损试验机进行磨损试验,研究了纳米Al2O3的体积分数、粒径对涂层喷焊性和耐磨粒磨损性能的影响。结果表明,Al2O3复合涂层的表面形貌细腻,颗粒加入能有效改善弥散相与镍基涂层的相容性,当纳米Al2O3的体积分数为2.0%时,涂层的耐磨性能最好为镍基涂层的2倍多,在相同的体积分数下,随着涂层中弥散强化相尺寸减小,涂层的耐磨性提高。     

钛合金耐磨微弧氧化制备技术的研究进展

钛合金质量轻,比强度高,尤其耐蚀性优异,在海洋、航空航天、医疗器械等领域应用越来越广泛.但钛合金硬度较低,摩擦因数高,粘着磨损、磨粒磨损和微动磨损倾向大,极大限制了其作为摩擦部件的应用.微弧氧化处理可以获得硬度高的陶瓷质膜,附着力强,既可以单独使用来提升钛合金的耐磨性,又能与多种后处理方式兼容,是提高钛合金耐磨性的有效方法.影响微弧氧化膜耐磨性的因素很多,详细论述了成膜电解液、电参数及不同复合处理方式对钛合金微弧氧化耐磨性的影响.电解液是决定微弧氧化膜耐磨性最关键的因素,通过选择合适的电解液体系或加入添加剂,使TiO2氧化膜中掺杂硬度更高的Al2O3、AlTiO5、SiO2等氧化物,大幅改善微弧氧化膜的耐磨性.通过调整电参数(包括恒流/恒压、单相/双相输出、频率等),将直接影响微弧氧化膜中硬质氧化物的类型、含量、分布、表面粗糙度等,进而影响摩擦磨损性能.复合处理包括微弧氧化膜表面机械抛光、喷涂石墨或聚四氟乙烯、磁控溅射硬质薄膜,以及氧化液中复合纳米颗粒等,其中复合纳米颗粒不仅可以修复膜层中的缺陷,还可以丰富氧化膜的相组成,使其具有耐磨、自润滑、耐腐蚀等多种功能特性,但纳米颗粒的分散、补加以及不同颗粒之间的协同影响还需要深入研究.     

Electroless Ni-P and Ni-P-Al2O3 Nanocomposite Coatings and Their Corrosion and Wear Resistance

In an effort to utilize beneficial aspects of nanoparticles in providing corrosion and wear resistance, electroless Ni-P and Ni-P-Al₂O₃ nanocomposite coatings were produced. Alumina particles with various contents from 5 to 20 g/L in bath were co-deposited within Ni-P deposits on mild steel (ms) substrate. Coatings were characterized by scanning electron microscopy (SEM) for morphology, energy dispersive analysis of x-ray EDAX for analyzing elemental composition and x-ray diffractometry for investigating the structural changes of their components. Electrochemical and immersion measurements were used to analyze corrosion behavior of the coatings in 3.5% NaCl solution. Wear resistance of the coating was measured by pin-on-disc method. The results indicated that the Ni-P-Al₂O₃ coatings provide the high hardness as compare to the Ni-P coating. Corrosion and wear resistance of coatings is observed to be superior to that of ms. Corrosion protection properties of the coatings are found to be affected with continuous exposure to the electrolyte. Coating with high concentration of alumina is exhibiting high wear resistance than Ni-P coating. Wear mechanism in case of Ni-P coating appears to be adhesive type and seems to change to abrasive type on introduction of alumina.     

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 将纳米Al2O3颗粒和镍基粉用湿法混合，采用等离子喷涂工艺制备了复合涂层。利用SEM和TEM分析了Al2O3复合涂层的表面形貌和微观组织，用磨粒磨损试验机进行磨损试验，研究了纳米Al2O3的体积分数、粒径对涂层喷焊性和耐磨粒磨损性能的影响。结果表明，Al2O3复合涂层的表面形貌细腻，颗粒加入能有效改善弥散相与镍基涂层的相容性，当纳米Al2O3的体积分数为20%时，涂层的耐磨性能最好为镍基涂层的2倍多，在相同的体积分数下，随着涂层中弥散强化相尺寸减小，涂层的耐磨性提高。     

20% Al2O3-SiO2(sf)/AZ91D镁基复合材料微弧氧化陶瓷层电化学腐蚀性能

在磷酸盐体系电解液中,对20%(体积分数)硅酸铝短纤维(Al2O3-SiO2)增强AZ91D镁基复合材料进行微弧氧化表面处理获得陶瓷层。利用扫描电子显微镜(SEM)和X射线衍射(XRD)仪分析陶瓷层的表面形貌、截面组织和相组成,采用动电位极化和电化学阻抗谱(EIS)测试评价微弧氧化陶瓷层的电化学腐蚀性能。结果表明,该陶瓷层主要由MgO和MgAl2O4相组成。陶瓷层的腐蚀电流密度比镁基复合材料基体低3个数量级,电化学阻抗大幅升高,耐腐蚀性能明显高于复合材料基体     

TC4 合金微弧氧化层的耐磨性和耐蚀性

目的对比不同电解液体系中制备的陶瓷膜层的耐磨损和耐腐蚀性能,判断实验条件下陶瓷膜性能最优的电解液体系。方法在相同的电参数工艺下,分别在Na Al O2,(Na PO3)6和Na2Si O3电解液体系中对TC4合金进行微弧氧化处理,处理时间为15 min。分析陶瓷层的表面形貌、成分和相结构。进行干摩擦条件下的摩擦磨损实验,对比TC4合金及三种陶瓷膜的耐磨性。通过测试极化曲线,对比TC4合金及三种陶瓷膜的耐蚀性。结果在Na Al O2,(Na PO3)6,Na2Si O3电解液体系中获得的陶瓷层表面呈现出多孔和局部凸起的相似表面特征,但相组成存在差异,主要相分别为Al2Ti O5,Al PO4和Ti O2。摩擦磨损实验表明,在10 N载荷下,以Si3N4陶瓷球作为摩擦配副,陶瓷层的磨损失重相对基材均显著减小,其中(Na PO3)6-陶瓷层失重约为基材的1/22。极化曲线分析表明,在模拟油田采出液作为腐蚀液的条件下,与TC4合金相比,陶瓷层的Ecorr显著正移,Jcorr明显减小,其中(Na PO3)6-陶瓷层的Ecorr从-0.311 V正移至0.777 V,Jcorr从9.634×10-7A/cm2减小到2.595×10-8A/cm2。结论微弧氧化处理能够显著改善TC4合金的耐磨性和耐蚀性,其中(Na PO3)6-陶瓷层的综合性能较好,有望满足TC4合金服役于油田环境时的要求。     

纳米Al2O3-40％TlO2复相陶瓷颗粒增强镍基合金复合涂层的摩擦学性能

运用等离子喷涂技术在7005铝合金表面制备Al2O3-40%TiO2纳米结构颗粒增强镍基合金复合涂层,分析其微观结构,研究其在不同载荷和速度条件下的摩擦磨损性能。结果表明：复合涂层主要由γ-Ni、α-Al2O3、γ-Al2O3和金红石型-TiO2等相组成,其摩擦因数和磨损失重较镍基合金涂层显著降低。在轻载3 N 时,复合涂层磨损表面的接触应力较低,主要发生微观切削磨损;当载荷上升至6~12 N时,接触应力高于磨损表面的弹性极限应力,复合涂层的磨损机理变为多次塑变磨损、微观脆性断裂磨损和磨粒磨损。随着速度的增大,磨损表面的接触温度逐渐升高,复合涂层以多次塑变磨损、疲劳磨损和粘着磨损为主。     

Microbial corrosion resistance of galvanized coatings with 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one as a biocidal ingredient in electrolytes

Electrodeposition of galvanized coatings from electrolyte containing 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT) can increase microbial corrosion resistance. Coatings were found to inhibit the growth and metabolism of sulphate-reducing bacteria (SRB). Open circuit potentials and corrosion rates of coupons revealed DCOIT effectively influences the coating property. Energy diffraction spectrum and infrared absorption spectra were used to detect DCOIT on the coating surface. Scanning electron microscopy and X-ray diffraction revealed morphological and structural modifications. Electrochemical impedance spectroscopy and polarization techniques determined the corrosion behaviour of coatings in SRB. Results showed coatings formed from electrolytes with DCOIT have improved microbial corrosion resistance and bactericidal action.     

Influence of WC addition in Co-Cr-W-Ni-C flame sprayed coatings on microstructure, microhardness and wear behaviour

In present paper the influence of the tungsten carbide (WC) particle addition on the microstructure, microhardness and abrasive wear behaviour of flame sprayed Co-Cr-W-Ni-C (EWAC 1006) coatings deposited on low carbon steel substrate has been reported. Coatings were deposited by oxy-acetylene flame spraying process. Wear behaviour of coatings was evaluated using pin on flat wear system against SiC abrasive medium. It was observed that the addition of WC particle in a commercial Co-Cr-W-Ni-C powder coating increases microhardness and wear resistance. Wear behaviour of these coatings is governed by the material parameters such as microstructure, hardness of coating and test parameters (abrasive grit size and normal load). Addition of WC in a commercial powder coating increased wear resistance about 4-9 folds. WC modified powder coatings showed better wear resistance at high load. Heat treatment of the unmodified powder coatings improved abrasive wear resistance while that of modified powder coating deteriorated the wear resistance. SEM study showed that wear of coatings largely takes place by microgroove, crater formation and scoring. Electron probe micro analysis (E.P.M.A.) of unmodified and WC modified powder coating was carried out for composition and phase analysis.     

1Cr17Ni4不锈钢金属和陶瓷等离子体喷涂工艺研究

1Cr17Ni4马氏体型不锈钢用作传动轴时耐磨损性能有待改善.采用等离子体喷涂方法在1Cr17Ni4马氏体型不锈钢表面制备Al2O3-TiO2 、Cr2O3陶瓷涂层和NiCrAlY金属涂层及NiCrAlY/ Al2O3-TiO2、NiCrAlY/ Cr2O3复合涂层,研究了它们的组织结构和磨损特性,讨论了喷涂工艺与耐磨损性能的关系.结果表明, Cr2O3涂层组织致密度高,与基体结合强度高,其耐磨性能好.提高喷涂功率时,Al2O3-TiO2、Cr2O3涂层致密度及与基体结合强度提高,其耐磨性能提高.合金涂层NiCrAlY的熔化状况和平化效果较陶瓷涂层优良,陶瓷涂层只有在较高喷涂功率时才有较好熔化和平化效果,而合金涂层在较低喷涂功率时,就可以得到较好的熔化和平化效果.陶瓷涂层Al2O3-TiO2、Cr2O3在磨损过程中的去除机制为断裂机制,金属涂层NiCrAlY在磨损过程中的去除机制为塑性变形机制.     

Abrasive wear/corrosion properties and TEM analysis of Al2O3 coatings fabricated using plasma electrolysis

Alumina coatings were deposited on Al alloy substrates using an electrolytic plasma technique, based on a dielectric barrier discharge created during anodic oxidation in an aqueous electrolyte. The substrate material (BS Al 6082) was biased anodically with an unbalanced AC high voltage. During processing, a plasma current density of 100 mA/cm² was used, at which a coating deposition rate of 1.67 μm/min was achieved. Coating abrasive wear and corrosion properties were assessed by conducting dry and wet rubber wheel abrasive tests and potentiodynamic polarization experiments, respectively. X-Ray diffraction (XRD) and transmission electron microscopy (TEM) were used to investigate the coating microstructure, and the coating/substrate interface. The property test results show that the coatings possess excellent abrasive wear and corrosion resistance. XRD analyses indicate that the coatings consist of α- and γ-Al₂O₃. An amorphous+nanocrystalline inner layer (1.5-μm thick) and a nanocrystalline (50–60 nm) intermediate layer in the coating were observed by TEM. The higher resistance to wear and corrosion can in part be attributed to the presence of these interlayers.