首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 109 毫秒
1.
为改善溅射依涂层与钼基体之间的结合力,在钼基体与依涂层之间制备了钨粘结层,并成功在钼丝网上制备了双层的铱/钨涂层。研究表明,钨粘结层的制备能有效改善铱涂层与钼基体之间的结合力,从而有效抑制铱涂层的剥落。对于制备态的样品,W粘结层与铱涂层以及钼基体之间未出现明显的互扩散。X射线衍射结果表明,溅射铱涂层为多晶结构且呈(111)择优取向生长。根据Movchan-Demchishin模型,所制备的双层铱/钨涂层的显微结构与"1区"结构类似,该结构表明所制备的涂层横向结合力弱,在拉应力状态下易发生开裂。  相似文献   

2.
炭/炭复合材料抗氧化抗热震铱涂层的研究进展   总被引:1,自引:0,他引:1  
铱是航天领域1800 ℃以上炭/炭复合材料抗氧化抗热震涂层的首选材料。本文介绍了物理气相沉积、金属有机物化学气相沉积、熔盐电解沉积和双层辉光等离子沉积等4种主要制备铱涂层的方法,讨论了铱涂层与炭/炭复合材料基体之间过渡层的材料选择,总结了铱涂层的地面试车测试结果,分析了影响铱涂层寿命的因素,指出今后我国制备铱涂层的技术途径应采用熔盐电解沉积 (Electroformed Deposition, 简写为ED)、双层辉光等离子沉积 (Double-glow Plasma Deposition, 简写为DPD)方法。  相似文献   

3.
无氢类金刚石涂层(ta-C)常用于提高刀具表面润滑性,提升极细微型钻头的排屑性能,降低断刀率。但ta-C涂层内应力大,与硬质合金钻头间的结合力较差,等离子溅射是提升涂层与基体之间结合力的有效方法。本文利用离子源产生的氩离子对硬质合金微型钻头和样块表面进行等离子体溅射,研究基体电流密度对基体表面形貌的影响;再利用阴极弧技术在等离子体溅射后的硬质合金表面制备ta-C涂层,研究不同溅射基体电流密度对ta-C涂层结合特性的影响。利用球盘式摩擦磨损试验机对溅射后的硬质合金表面以及ta-C涂层摩擦系数进行测试。通过钻孔测试,研究钻孔过程中基体电流密度对涂层与基体结合特性以及涂层微型钻头断刀率的影响。结果表明,随着溅射基体电流密度的增加,基体表面钴含量逐渐减少。压痕测试结果显示,合理的溅射基体电流密度(19.1 mA/cm2)下,可得到高结合力等级(HF1)。高结合力等级的ta-C涂层,摩擦系数最低为0.096。涂层钻头加工通信印制电路板1000孔后,高结合力ta-C涂层钻头的槽内涂层无异常脱落,测试1000支后无断刀。  相似文献   

4.
为改善TiO2溅射靶材主要依赖进口的局面,采用大气等离子喷涂技术在不锈钢SUS304平板基体及管状基体上制备了TiO2涂层。利用扫描电子显微镜对涂层形貌进行了观察,并对涂层与基体的结合强度、涂层孔隙率及抗热震性能分别进行了表征。结果表明:粉末熔化及铺展良好,截面可见典型层状结构。涂层与基体以机械结合为主,断裂基本发生在基体与粘结层界面处;涂层的孔隙率较低,同时具有良好的抗热震性能。厚涂层制备过程中,采用循环水冷却方法对不锈钢SUS304管状基体进行冷却,涂层沉积速度快且无开裂和脱落,涂层厚度可达8 mm。通过对冷却装置的改进及喷涂工艺的进一步优化,有望在大尺度管状基体上制备厚涂层以满足溅射蒸镀辊的需要。  相似文献   

5.
使用等离子喷涂方法制备出双层热障涂层(粘结层为Ni-Cr-Al-Y,陶瓷层为ZrO2).使用ABAQUS有限元分析软件,采用间接耦合分析的方法,模拟计算了喷涂过程中陶瓷层/粘结层间三维结构椭圆界面的应力场分布,得出了粘结层表面三维椭球形貌单元位置和尺寸与热应力分布之间的关系.模拟结果表明,涂层制备后,椭球形貌单元位置和...  相似文献   

6.
钼基体上化学气相沉积钨功能涂层的研究   总被引:7,自引:1,他引:6  
采用CVD(Chemical Vapor Deposition)法沉积的钨涂层有[100]/[111]/[110]择优取向。择优取向主要受气体组分、流动速度、温度等因素的影响。研究了钼基体上CVD钨涂层的表面形貌和织构、涂层界面的元素分布、涂层的抗热震性能及高温扩散性能。结果显示:钨涂层与基体钼有2μm左右的互扩散层且钼在钨中的扩散速度更高;涂层在通H2条件下,进行室温→1400℃→室温20次循环后涂层不脱落、界面没有明显变化,涂层结合力好;涂层界面上的杂质元素氧等影响涂层的结合性能。  相似文献   

7.
吴王平  陈照峰  丛湘娜 《贵金属》2012,33(3):10-14,21
采用双辉等离子技术分别在抛光、氧化和高温热处理的C/C复合材料表面制备贵金属铱涂层。C/C复合材料和铱涂层的表面微观结构通过扫描电镜观测。结果表明:在抛光的C/C复合材料表面获得沉积较好、覆盖良好的铱涂层,但铱涂层表面出现微裂纹。微裂纹出现是由于较高沉积温度下涂层与基体之间的热膨胀系数不匹配导致的。氧化和高温热处理的C/C复合材料基体表面出现较大间隙和缺陷,铱涂层没能完全覆盖其表面,需多次沉积填满这些缺陷。  相似文献   

8.
采用电热爆炸喷涂和等离子喷涂联合制备热障涂层,以电热爆炸喷涂法在DZ125合金表面制备NiCoCrAlY粘结层,以等离子喷涂技术制备陶瓷顶层。利用扫描电镜(SEM)和X射线衍射(XRD)仪对所制备的粘结层进行分析,结果表明:电热爆炸喷涂的粘结层与基体结合良好,喷涂态的粘结层的相主要由Ni3Al组成。采用联合法制备的热障涂层,在喷涂态的陶瓷层、粘结层、基体3者结合良好,界面清晰。在高温热循环过程中,粘结层/陶瓷层界面间生成了连续、致密的Al2O3膜,阻碍粘结层的氧化。粘结层/TGO界面产生平行于界面的裂纹,是导致热障涂层失效的主要原因。  相似文献   

9.
采用放电等离子体烧结技术制备了以难熔金属钼为界面涂层的连续钨纤维增韧钨复合材料,研究复合材料拉伸脆-韧转变温度,分析和探讨钼涂层在复合材料断裂中的作用以及对Wf/W复合材料断裂模式的影响。结果表明:复合材料在400℃及以下均发生脆断,从400℃开始,纤维与基体界面出现曲形裂纹,涂层有减弱钨基体和钨纤维界面结合强度的迹象。500℃时复合材料出现韧性断裂,韧性主要来源于纤维带来的伪韧性。钼作为界面涂层有助于发动纤维脱粘-韧断增韧机制,但涂层本身由于特殊结构取向并无预期的钼塑性变形带来增韧贡献。同时开展了Wf/W复合材料的瞬态热冲击测试,高强韧、低韧脆转变温度(DBTT)的钨纤维比粗晶基体更能抗热冲击损伤。  相似文献   

10.
采用电子束物理气相沉积技术(EB-PVD)在镍基单晶合金N5基体上制备了双层热障涂层(粘结层+陶瓷层)和三层热障涂层(粘结层+混合层+陶瓷层),并对2组涂层体系的热循环性能进行1100℃保温5 min水冷的热震实验,采用扫描电镜、能谱仪以及X射线衍射对其微观组织结构进行了分析。研究发现,在粘结层和陶瓷层之间添加的混合层(NiCrAlY+YSZ)能够延缓TGO层的生长,并具有缓解内应力的作用,两者的共同作用使得三层结构的热障涂层表现出更为优异的热匹配性。  相似文献   

11.
Abstract

Dense and uniform coatings of iridium (Ir), 5–7 μm in thickness, were deposited onto molybdenum (Mo) substrates by double glow plasma discharge in the temperature range of 800–850°C at 35 Pa. During deposition, the Mo substrate was biased at a voltage of ?300 V while the 99·9% Ir target was at a bias voltage of ?800 V. After deposition, the Ir coating was ablated using an oxyacetylene torch with a flame temperature of ~2000°C to determine the high temperature stability of the coated substrate. The morphology and microstructure of the Ir coating were observed using scanning electron microscopy while the composition and structure were measured using X-ray diffraction and energy dispersive spectroscopy. The thickness of the as deposited Ir coating was uniform and the interface between the coating and the substrate exhibited excellent adhesion with no evidence of delamination and cracks. After exposure to the flame, the surface of the as ablated coating presented imperfections including pores, bulges and cracks; however, the Ir coating retained sufficient adhesion to limit the weight loss of the Ir coated Mo substrate to 10 mg cm?2 s?1.  相似文献   

12.
通过离子镀方法,在难熔金属Mo表面成功制得Ir涂层,制得的Ir涂层呈亮银白色且表面均匀,并分别采用X射线衍射及扫描电镜技术对其结构和微观形貌进行分析。结果显示:涂层均匀致密呈山丘状,无明显缺陷,Ir涂层呈多晶态,并沿(111)晶面优先生长,Ir涂层与基材结合良好,铱涂层抗氧化性能良好。  相似文献   

13.
The thermal-barrier coatings (TBC) sprayed on hot-section components of aircraft turbine engines commonly consist of a partially stabilized zirconia top-coat and an intermediate bond-coat applied on the metallic substrate. The bond-coat is made of an aluminide alloy that at high engine temperatures forms thermally grown oxides (TGO). Although formation of a thin layer of aluminum oxide at the interface between the ceramic top-coat and the bond-coat has the beneficial effect of protecting the metallic substrate from hot gases, oxide formation at splat boundaries or pores within the bond-coat is a source of weakness. In this study, plasma-sprayed TBC specimens are manufactured from two types of bond-coat powders and exposed to elevated temperatures to form oxides at the ceramic-bond-coat boundary and within the bond-coat. The specimens are then tested using nondestructive evaluation (NDE) and destructive metallography and compared with the as-manufactured samples. The objective is to determine if NDE can identify the oxidation within the bond-coat and give indication of its severity. While ultrasonic testing can provide some indication of the degree of bond-coat oxidation, the eddy current (EC) technique clearly identifies severe oxide formation within the bond-coat. Imaging of the EC signals as the function of probe location provides information on the spatial variations in the degree of oxidation, and thereby identifies which components or areas are prone to premature damage.  相似文献   

14.
超精密(纳米精度)模仁是模造技术制备玻璃镜片的核心部件,而模仁表面的保护涂层则决定着模仁的使用寿命及玻璃制件的成型质量与成本。本研究采用射频磁控溅射技术,在WC模仁基材表面分别镀制Re、Ir单层膜及Re/Ir复合多层膜三种膜系。通过扫描电子显微镜、表面轮廓仪、X射线衍射仪以及纳米压痕仪等对所制备涂层的表面形貌、结构以及涂层力学性能进行表征,同时采用高温润湿角测量仪结合常用的镜头玻璃硝材D-ZK3与模仁进行高温浸润测试。结果表明,涂覆三种膜系后模仁力学性能及抗玻璃高温黏连性能都得到了明显改善,且Re/Ir多层膜系综合性能优于Re和Ir单层膜系,在延续基材表面精度的同时,较大幅度地提高了模仁表面硬度及弹性模量,高温状态下与玻璃硝材浸润性明显减弱,接触界面未观察到元素互扩散现象,显示良好的应用前景。  相似文献   

15.
电热定向爆炸制备高速钢涂层的试验研究   总被引:1,自引:0,他引:1  
采用电热爆炸定向喷涂工艺在45钢基体上制备W6Mo5Cr4V2(M2)高速钢涂层。借助扫描电镜、显微硬度计分别对涂层显微组织、孔隙率、涂层基体界面结合以及涂层的硬度进行了测试。结果表明,电热爆炸定向喷涂制备的涂层组织晶粒明显细化,涂层孔隙率低;涂层与基体界面为冶金结合,且结合良好,存在一个熔合区;涂层硬度均明显高于W6MoSCr4V2喷涂材料原始硬度,最高达到954HV。  相似文献   

16.
Dense and adherent Ir coating was deposited on porous WC ceramic by double glow plasma (DGP). There were two cathodes in the vacuum deposition chamber. The bias voltage of Ir target and WC substrate were ?900 and ?350?V, respectively. The Ir coating was characterized using scanning electron microscopy, x-ray diffraction, nanoindentation instrument, and scratch tester to examine the microstructure and the mechanical properties. The results indicated that the deposition rate by DGP was up to 5-6???m/h which was faster than that by metal-organic chemical vapor deposition and magnetron sputtering. The Ir coating had a preferential growth orientation of (220) crystal face. The hardness was 800?HV. The elastic modulus was 644?GPa. The excellent mechanical properties were attributed to the preferential growth, the large compressive stress, and the shrinkage of the lattice parameters. The adhesive force was up to 51?N. The strong adhesion was attributed to the mechanical locking and chemical reaction between the Ir coating and the porous WC substrate.  相似文献   

17.
In this paper, the failure behavior of plasma-sprayed yttria-stabilized zirconia thermal barrier coatings fabricated by atmospheric plasma spraying (APS-TBCs) under three-point bending (3PB) test has been characterized via acoustic emission (AE) technique. Linear positioning method has been adopted to monitor dynamic failure process of the APS-TBCs under 3PB test. The investigation results indicate that the variation of AE parameters (AE event counts, amplitudes and AE energy) corresponds well with the change of stress–strain curve of the loading processes. The failure mechanism was analyzed based on the characteristics of AE parameters. The distribution of frequency of crack propagation has been obtained. The AE signals came from two aspects: i.e., plastic deformation of substrates, initiation and propagation of the cracks in the coatings. The AE analysis combined with cross-sectional observation has indicated that many critical cracks initiate at the surface of the top-coat. And some main cracks tend to propagate toward the substrate/bond-coat interface. The actual failure mechanism of the APS-TBCs under 3PB test is attributed to the debonding of metallic coating from the substrates and the propagation of the horizontal crack along the substrate/bond-coat interface under the action of flexural moment.  相似文献   

18.
李乔磊  宋鹏  黄太红  邓春明  孙晓峰 《表面技术》2021,50(3):79-90, 100
热喷涂陶瓷涂层在航空航天、交通运输等众多领域具有广阔的应用前景,常见的热喷涂陶瓷涂层体系包括陶瓷层、金属/合金粘结层和金属基体.由于陶瓷层与粘结层具有较大的物化性能差异,使界面成为热喷涂陶瓷涂层易发生失效的区域,极大降低了涂层的服役寿命,遏制了热喷涂陶瓷涂层更为广泛的应用.以热喷涂界面的微观和宏观结构设计为出发点,综述了微观界面和扩散对界面力学性能的影响,总结了微米-纳米颗粒的界面结构、成分连续梯度变化的涂层结构和涂层缺陷对性能的影响.同时总结了三点弯曲、显微硬度和纳米压痕对界面力学性能的系统表征方法,并结合不同测试方法的特性,给出了对应的多尺度界面力学性能的计算公式.上述结果对设计和制备高性能复合涂层具有重要的理论意义,对延长涂层服役寿命具有实际的应用价值.  相似文献   

19.
基于正交试验设计,采用射频磁控溅射技术在不同工艺条件下制备了一系列纯金属Mo薄膜。以薄膜的纳米硬度和结合强度为评价指标,考察分析了溅射靶功率、基片温度、氩气流量和真空度4个工艺参数对溅射Mo薄膜综合力学性能和组织结构的影响规律及机理。结果表明,所制备的多种Mo薄膜均为立方多晶结构,并在(110)和(220)晶面择优生长。薄膜由细小的"树枝"状颗粒随机堆叠而成,表面呈压应力状态。综合考虑薄膜的沉积质量和沉积效率,提出磁控溅射制备Mo薄膜的较佳工艺参数为Mo靶功率100 W,沉积温度120℃,氩气流量90 cm3/min,真空度0.2 Pa。采用优化工艺制备的Mo薄膜具有良好的结晶状态和均匀致密的组织结构,纳米硬度为7.269 GPa,结合强度高达33.8 N。  相似文献   

20.
For Ni-based single crystalline superalloy with high temperature protective coatings, the formation of detrimental phases in the superalloy substrate resulting from interdiffusion between the coatings and the substrate significantly degrades the mechanical properties of the substrate. In this paper, a novel (Ru,Ni)Al/NiAl diffusion barrier coating was produced by electrodeposition of Ru together with electron beam-physical vapor deposition of Ni–Al layer. The microstructure and diffusion barrier behavior of the (Ru,Ni)Al/NiAl coating was investigated by scanning electron micrograph (SEM) equipped with energy dispersive spectroscopy (EDS). SRZ mainly consisting of P phase and other TCP phases were presented beneath the NiAl coating due to the interdiffusion between the coating and Ni-based superalloy. The (Ru,Ni)Al layer effectively slowed down inward diffusion of Al from the coating and outward diffusion of alloying elements such as W and Mo, therefore suppressed the formation of TCP phases and SRZ.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号