纳米ZrO2等离子涂层的结构,性能和工艺特点

采用大气等离子喷涂技术(APS)，制备了常规氧化锆和纳米结构氧化锆两种涂层．利用扫描电镜(SEM)对涂层的显微结构进行了观察．对两种涂层的沉积效率、表面粗糙度和显微硬度作了对比研究．结果表明，粉末原料的显微结构、粒度、形态、喷涂工艺参数(喷涂功率和距离)对涂层的显微结构有较大的影响．等离子喷涂造粒纳米氧化锆粉制备的涂层沉积效率高而稳定，其显微结构与喷涂功率和距离密切相关．与常规氧化锆涂层相比，纳米结构氧化锆涂层具有较高的显微硬度和较低的表面粗糙度．     

等离子喷涂制备MoSi2-CoNiCrAlY纳米复合涂层的结构与性能

以高能球磨法制备的MoSi2-CoNiCrAlY复合粉末为喂料,利用等离子喷涂技术在GH4169合金表面沉积了MoSi2-CoNiCrAlY涂层,采用X射线衍射仪、激光粒度分析仪和扫描电镜分析了粉末喂料及涂层的相组成和微观结构,并对涂层的显微硬度、抗热震性以及低温氧化行为进行了研究。结果表明:采用高能球磨法制备的粉末喂料是由细小纳米晶组成的多晶体,略为过筛后可直接用于热喷涂;制备的涂层组织致密,孔隙率低,且与基体形成了一定的冶金结合;其显微硬度服从威布尔分布,平均硬度值高达854.4HV0.1,热震失效寿命长达27次,500℃氧化120h后质量增加仅为0.083mg/cm2,且未发生MoSi2的"低温粉化"现象。     

等离子喷涂Al_2O_3-13%TiO_2涂层微观组织结构与力学性能分析

采用等离子喷涂技术在钢基体上表面制备了Al2O3-13%TiO2涂层,喷涂粉末分别采用微米和纳米结构,测试了涂层的显微硬度;采用定量分析软件测定了涂层孔隙率并通过扫描电镜分析了涂层的显微组织;采用拉伸试验机测试了涂层的结合强度。结果表明,微米粉制备的Al2O3-13%TiO2涂层具有明显的层状结构,纳米粉制备的Al2O3-13%TiO2涂层在层状结构的基础上镶嵌有大量的未融化和部分融化的粒子;纳米Al2O3-13%TiO2涂层粒子间结合紧密,孔隙率低,结合强度高,显微硬度高。     

氮气冷喷涂NiCoCrAlY及NiCoCrAlY/ZrO2涂层的结构与硬度特征

以氮气作载气,采用冷喷涂技术成功地制备了NiCoCrAlY涂层及NiCoCrAlY/ZrO2复合涂层,并研究了涂层表面和横截面的微观结构、粒子之间的结合变形情况以及涂层的显微硬度.结果表明,以氮气作栽气的冷喷涂技术可以制备出结构较致密、硬度高(400～600HV)的NiCoCrAlY涂层;加入氧化锆能提高涂层的显微硬度;粉末颗粒在沉积过程中会发生强烈的塑性变形,变形颗粒边缘处含氧量较高.     

超音速等离子喷涂PZT涂层的结构与性能研究

锆钛酸铅(PZT)是一种应用广泛具有优良压电性能的功能材料,采用超音速等离子喷涂的方法在45#钢基体表面制备了PZT陶瓷涂层,采用X射线衍射(XRD)对烧结粉末和PZT涂层相组成进行了检测,利用场发射扫描电子显微镜(SEM)对粉末和喷涂层形貌进行了观察,利用TEM透射电子显微镜对涂层的微观结构进行了分析,并对涂层的显微硬度以及介电性能进行了测试。结果表明,超音速等离子喷涂制备的PZT涂层表面平整,结构致密,孔隙率为1.6%,平均显微硬度为562.3 Hv,居里温度为370℃。     

等离子喷涂 AP40生物活性玻璃陶瓷涂层的结构和性能

采用大气等离子喷涂技术，在TiA16V4基体上制备了AP40玻璃陶瓷涂层．利用光学显微镜、SEM和XRD分析技术对涂层形貌、显微组织结构和相组成进行了研究．探讨了热处理工艺对涂层组织结构及其性能的影响，并按德国DIN 50160标准进行涂层的拉伸强度试验．结果表明：等离子喷涂AP40玻璃陶瓷涂层在喷涂态，只有较低的结晶度．喷涂工艺对涂层的孔隙率和粉末沉积率有较大的影响．合适的热处理工艺可提高涂层的结晶度，减少孔隙以及提高结合强度．     

不同喷涂工艺下NiCoCrAlYTa涂层的显微结构和性能

为探索不同喷涂工艺对NiCoCrAlYTa涂层的显微结构和性能的影响规律,确定最优工艺,采用大气等离子、低压等离子、常规超音速火焰和低温超音速火焰4种工艺在镍基单晶高温合金表面制备了NiCoCrAlYTa涂层。采用X射线衍射(XRD)、扫描电镜(SEM)和显微硬度计等分析手段对喷涂态涂层的相组成、显微结构和显微硬度等进行了表征。结果表明,不同喷涂工艺下涂层的相组成均为γ′-Ni_3Al、β-NiAl和γ-Ni固溶体。低压等离子和超音速火焰喷涂的涂层致密且孔隙率低,其中超音速火焰喷涂的涂层孔隙率低于1%。低压等离子和低温超音速火焰喷涂的涂层氧含量很低,控制在0.3%~0.6%的范围。综合来说,低温超音速火焰喷涂工艺制备的涂层结构致密,孔隙率和氧含量很低。该工艺是沉积NiCoCrAlYTa涂层的首选。     

不同Al2O3-TiO2-Cr2O3-SiO2配比等离子喷涂层的耐磨粒磨损性能

为了探讨等离子喷涂制备Al2O3-TiO2-Cr2O3-SiO2层的可行性及其喷涂层的耐磨性,采用等离子喷涂在Q235钢表面分别制备了54%Al2O3-36%TiO2-10%Cr2O3-0.5%SiO2,42%Al2O3-28%TiO2-28.5%Cr2O3-1.5%SiO2和30%Al2O3-20%TiO2-47.5%Cr2O3-2.5%SiO23种陶瓷层,分析了陶瓷涂层的金相显微形貌、显微硬度及耐磨粒磨损性能,并分析了其耐磨粒磨损的机理。结果表明:3种涂层的显微硬度分布均具有梯度分布特性,Al2O3+Cr2O3硬质相含量越高,涂层硬度越大;30%Al2O3-20%TiO2-47.5%Cr2O3-2.5%SiO2喷涂粉制成的涂层的硬度最大,耐磨粒磨损性能最佳。     

纳米陶瓷等离子喷涂层硬度的Weibull分布及与涂层组构的对应特性

等离子喷涂层的硬度是反映其耐磨性、强度、使用寿命的重要指标,它与涂层的组构有对应的关系,但其测定结果分散性较大。为了精确测量陶瓷等离子喷涂层的硬度,在NiCrAl合金表面等离子喷涂制备了Al2O3-13%TiO2(AT13)纳米陶瓷涂层(ncc)和对照用微米涂层(mcc),采用显微硬度测试仪测量了其显微硬度,研究了其Weibull分布特性,通过SEM、XRD等分析了ncc涂层显微硬度与微观组织结构的关系,并通过TEM对涂层的微区结构进行了表征。结果表明:ncc涂层的平均显微硬度显著高于mcc,且呈双态分布;两者硬度的Weibull分布呈分散性,但ncc涂层的分布较均匀,微裂纹细小且粒径小,以α-Al2O3和γ-Al2O3及少量金红石型TiO2为主要物相;ncc涂层具有优异的力学性能主要归因于其组织的晶粒细化、纳米TiO2颗粒镶嵌于Al2O3孔隙中、Al2O3微晶弥散分布、微裂纹韧化等。     

Cr2O3 梯度涂层的组织与耐磨性研究

采用等离子喷涂技术设计并制备了耐磨梯度涂层。涂层组织,以及显微硬度和磨损率测量结果表明,从基体到陶瓷层,通过涂层成分的逐渐变化,涂层的组织及性能均具有梯度涂层的特征。     

涂布刮刀表面等离子喷涂纳米AI203—13％Ti02涂层的特性

为了深入研究纳米A1203-13％TiO：（ATl3）涂层的组织、性能与喷涂工艺参数之间的关系,采用正交试验法对等离子喷涂工艺的电流、电压、送粉率和喷涂距离等参数进行了优化,在涂布刮刀表面制备了纳米ATl3涂层。采用金相显微镜,SEM,EPMA和XRD等对纳米ATl3涂层的组织、磨粒磨损性能和结合强度进行了分析。结果表...     

Synthesis and characterization of nanocrystalline CoCr coatings by plasma spraying

The present paper describes the synthesis and characterization of nanocrystalline CoCr (ASTM F75) coating produced by plasma spraying for possible surgical implant applications. The feedstock powders were synthesized by mechanical milling to produce irregular agglomerates with an average grain size of less than 100 nm. The powders were then introduced into an argon plasma spray to successfully produce a nanocrystalline coating. Scanning electron microscopy and transmission electron microscopy were used to study the morphology of the nanometric particles and the resultant sprayed coatings. Microhardness and porosity measurements were performed on the conventional and the nanocrystalline coatings to characterize and compare the physical and mechanical properties.     

等离子喷涂A12O3＋13%TiO2陶瓷涂层的组织结构及其耐磨性

本文用Ｘ射线衍射、扫描电镜等研究了等离子喷涂Ａ１２Ｏ３＋１３％ＴｉＯ２（质量分数）陶瓷涂层的相结构、相组成及其组织特征。陶瓷涂层孔隙率低,致密程度较高,以亚稳相ｒ－Ａ１２Ｏ３为主要相,同时存在α－Ａ１２Ｏ３和金红石ＴｉＯ２。富Ａ１２Ｏ３区与富ＴｉＯ２区呈明显相互交迭的层状结构,且存在相互成分扩散,另外涂层设计对硬度有一定影响,ＴｉＯ２的引入提高了涂层的耐磨性。     

Characteristics of Plasma-Sprayed Ceramic Coatings and Their Engineering Application

The microstructure, porosity, microhardness and adhesive strength of three plasma- sprayed ceramic coatings (Al2 O3, Cr2 O3 and Cr3 C2 NiCr) were tested. The wear resistance of the coatings was characterized through sand blasting test. The results showed that the erosion resistance of Cr2 O3 coating was better than Al2 O3 and Cr3 C2 NiCr coatings'.Through depositing the coating on the surface of boiler overheater tubes and on the surface of baffle- wall of carrying- coal grain blower to test its anti- erosion performance after a period of running, it was confirmed that the coatings present excellent wear resistance. Accordingly, it also demonstrates that ceramic coating has a promising prospects in surface protection in thermal power stations.     

莫来石粉末化学镀镍和涂层的高温摩擦学性能

先进行正交试验优化镀液的工艺参数,然后用化学镀对莫来石粉末进行表面包覆并对包覆粉末进行850℃热处理,用等离子喷涂技术在304不锈钢表面分别制备莫来石涂层和包覆粉末涂层。用附带能谱的扫描电镜(SEM)和X射线衍射仪(XRD)表征了包覆粉末和涂层的微观结构,用HV-1000维氏显微硬度仪测试了涂层硬度,用HT-1000摩擦实验机测试了800℃时涂层的摩擦磨损性能。结果表明：镀液的优化工艺参数为：硫酸镍20 g/L,次磷酸钠30 g/L,柠檬酸钠20 g/L,氯化铵20 g/L,pH=5.5,水浴温度80℃,施镀时间1 h。在莫来石粉末表面包覆的Ni-P镀层均匀致密,热处理使包覆镀层由非晶态向晶态转变,生成了Ni和Ni3P相。莫来石涂层主要由莫来石相和γ-Al2O3相组成,包覆粉末涂层主要由Ni、AlNi3、Ni3P和莫来石相组成。在包覆粉末涂层中引入Ni-P镀层使涂层的硬度由417.5 HV0.2提高到500.1 HV0.2。包覆粉末涂层的耐磨性优于莫来石涂层,包覆粉末涂层的摩擦系数比莫来石涂层明显减小,包覆粉末涂层的磨损率为13×10^-4 mm³     

Kevlar纤维缝纫泡沫芯材复合材料力学性能研究

基于热压罐成型工艺,制备了kevlar纤维缝纫泡沫芯材复合材料夹层板,并通过扫描电镜观察了胶膜中的树脂在kevlar纤维束之间的浸润状态,为工程化应用提供参考.选取未缝纫泡沫夹芯复合材料和碳纤维预浸料缝线缝纫泡沫芯材复合材料夹层板为对比试样,实验研究了kevlar纤维缝纫泡沫芯材复合材料夹层板的平压、剪切和侧压力学性能,并考察了缝纫针距、行距的变化对其力学性能和破坏模式的影响.研究表明:在真空压力下,胶膜中的树脂与kevlar纤维浸润良好;对泡沫芯材进行kevlar纤维缝纫增强后,其力学性能显著提高,并改变了夹层板的破坏机理.实验范围内,随着缝纫密度的提高,平压强度和模量增大;夹层板剪切性能和侧压性能受缝纫密度的影响较大,在缝纫参数(缝纫行距×针距)为10 mm×10 mm时,增强效果较佳,其剪切强度和侧压强度分别提高了44%和21%,剪切模量和侧压模量分别提高了34%和127%.     

AYSZ涂层的制备及显微结构与性能研究

采用振动研磨方法对喷涂前驱体(6%Al2O3-7%YSZ混合粉体)进行研磨处理,并通过XRD和TEM对研磨后的混合粉体进行表征.利用大气等离子喷涂技术,分别对研磨过的前驱体和7%YSZ粉体进行喷涂,制备了新型AYSZ涂层和常规YSZ涂层,采用SEM,XRD和EDS等测试方法,研究了这两种涂层的显微组织及相组成.研究结果表明:前驱体颗粒经过振动研磨后,产生大量的应变和位错等缺陷,使材料处于亚稳、高能活性状态.在等离子高温的诱导下,储存在材料内部的能量得以释放,使得AYSZ涂层的柱状晶粒尺寸减小至纳米级.相比于YSZ涂层,AYSZ涂层含有较多的c-ZrO2,提高了涂层的孔隙率、弹性模量和硬度等性能.     

Effect of powder structure on the structure of thermally sprayed WC-Co coatings

Five representative types of WC-Co powders were selected to clarify the dependence of the structure of sprayed coatings on the structure of powders themselves. The WC-Co coatings were sprayed with the Jet-Kote process and plasma spraying as well. The structure of WC-Co coatings was primarily characterized by X-ray diffraction. The X-ray diffraction patterns of the sprayed coatings were illustrated compared with those of powders, which aims at a better understanding of the structure of thermally sprayed WC-Co coatings. The selected coating was also analysed by differential scanning calorimetry (DSC). The decarburizing process, and the effects of powder structure and spray conditions on the crystal structure of sprayed WC-Co coatings are discussed in detail.     

Study of the microstructure of plasma sprayed coatings obtained from Al2O3–13TiO2 nanostructured and conventional powders

The microstructure of coatings obtained from nanostructured or conventional Al₂O₃–13TiO₂ powders and deposited by plasma spraying technique on low-carbon steel was examined by transmission electron microscopy techniques. The dominating phase in both coatings was γ-Al₂O₃ phase. It has been observed that the grains of γ-Al₂O₃ grew in various shapes and sizes, that are particularly visible in the case of coating sprayed from nanostructured powder. The coatings obtained from the fully melted conventional powders exhibited a typical lamellar microstructure, into which the strips of TiO₂ phase were extended. The microstructure of coatings produced from agglomerates of nanostructured particles also revealed the regions consisting of partially melted α-Al₂O₃ powders surrounded by the net-like structure formed from fully melted oxides that improved the coating properties. Along with the observed morphology diversity some changes in the chemical composition on the cross sections of obtained coatings have been also noticed.