微弧氧化制备阻氚涂层的研究

通过微弧氧化技术在316L不锈钢表面制备了氧化铝阻氚涂层。研究了不同微弧氧化工艺参数对涂层相结构、表面形貌、膜厚的影响,并分别通过XRD、SEM、涡流法进行了分析。通过划痕实验、抗热震实验、气相氘渗透试验,经过分析得到了制备最佳涂层的工艺参数。结果表明：涂层相结构、表面形貌、膜厚受到微弧氧化电流密度、电压及反应时间的影响。电流密度、电压能过影响涂层相结构,电流密度增大时更多铝相变成氧化铝相,电压增大时将促进α相氧化铝的形成;增大电压及反应时间,膜层表面不均匀质量变差,电流密度为9A/dm2时,膜层表面形貌最佳;膜层厚度受到电流密度、电压及反应时间的影响。经过一系列的测试（划痕实验、抗热震实验、气相氘渗透试验）,发现参数为6A/dm2, 300V, 30min时,得到了膜基结合力为 86.0N、能抗280次热震、阻氚性能至少达达3数量级的涂层。     

离子注入法在316L不锈钢基体上制备Al2O3 阻氚涂层

采用离子注入技术在316L不锈钢基体上制备了氧化铝阻氚涂层。对离子注入法的不同工艺参数对α-Al₂O₃涂层摩擦磨损、耐腐蚀、抗热震、阻氚性能的影响进行了研究。结果表明：温度、加速电压及离子注入剂量对α-Al₂O₃的含量均有影响。温度升高时, α-Al₂O₃的含量增加。增大加速电压及离子注入剂量时,α-Al₂O₃含量均出现先升高后降低的规律。离子注入剂量对涂层的摩擦磨损、耐腐蚀性能影响比较大：离子注入剂量越大,涂层的耐磨、耐腐蚀性能越好。涂层经过200次热震测试后未发生变化,抗热震性能较好。Al₂O₃膜层具有优异的阻氚性能,在600 ℃下能使316L不锈钢的氚渗透率降低3个数量级。     

FeAl/Al_2O_3复合阻氚涂层制备技术的研究进展

FeAl/Al_2O_3复合膜层是聚变堆氚增殖包层及辅助涉氚系统结构材料首选的阻氚涂层。其制备过程通常需要铝化和氧化2个步骤,铝化是Al原子与基体Fe原子通过相互扩散在基体表面形成铁铝固溶体(Fe,Al)或Fe-Al金属间化合物过渡层;氧化是使铝化涂层表面选择性氧化形成Al_2O_3膜。该阻氚涂层的制备可采用物理气相沉积(PVD)、化学气相沉积(CVD)、热浸铝化(HDA)、包埋渗铝(PC)、等离子体喷涂(PS)和电化学沉积(ECD)等技术。相对而言,CVD、HDA和PC等3种技术有较好的应用前景,有望成为聚变堆中FeAl/Al_2O_3阻氚涂层工程化制备的候选技术而ECD技术因其制备过程容易控制、涂层性能稳定、可涂镀复杂结构件等特点在FeAl/Al_2O_3阻氚涂层制备方面颇具吸引力。     

聚变堆结构材料表面阻氚涂层的制备与展望

核聚变能作为一种清洁可持续能源,对人类社会发展面临的能源问题有着重要研究意义。聚变堆燃料主要为氘和氚,虽然氘在地球上储量丰富,但氚却需要通过聚变堆附属的氚工厂来自给自足。因此,如何防止燃料尤其是氚的泄漏损失,并防止结构材料损伤成为聚变堆正常运行的关键。在聚变堆系统中存在着大量结构钢材料,如316L和RAFM钢,在其结构材料表面应用阻氚涂层可以有效地阻止氚渗透损失并保护材料。主要综述了国内外阻氚涂层的种类以及制备方法,并对阻氚涂层的发展进行了展望。     

低温等离子复合技术制备氧化铝阻氚涂层（英文）

采用低温等离子复合技术,先后经过磁控溅射镀铝,热处理及氧离子注入,在不锈钢基体上制备了氧化铝阻氚涂层。利用XRD、SEM、EDS、AES对涂层进行了相结构、表面形貌、成分、氧元素分布等分析,并进行了划痕试验、抗热震及阻氚性能测试。结果表明:磁控溅射获得了高质量的铝涂层,热处理后形成了Fe Al合金过渡层。在氧离子注入中,当注入剂量不变电压增加时,离子注入深度增加,而氧元素分布梯度降低;当注入剂量达到8×10~(17) ions/cm~2以上时,氧元素分布变得均匀。所获得的氧化铝涂层具有较好膜/基结合力、抗热震性能及阻氚性能。经过叠加电压注入且剂量达到8×10~(17) ions/cm~2的膜层具有最好的阻氚性能,在600℃能使不锈钢的氚渗透率降低3个数量级。     

氧化物陶瓷阻氚涂层的研究进展

利用阻氚涂层(TPB)降低结构材料中的氚损失,是聚变堆发展中的热点研究之一。陶瓷具有低氚渗透性、耐腐蚀性、高硬度和高热稳定性等特性,是目前聚变堆阻氚涂层首选材料。相对于硅化物、钛基等非氧化物陶瓷材料,氧化物陶瓷涂层具有熔点高、化学性质稳定、耐腐蚀性和阻氚渗透因子(PRF)高等优势,因此针对氧化物陶瓷阻氚涂层的研究较多。主要综述了单一氧化物陶瓷、复合氧化物陶瓷阻氚涂层近年来的研究现状与发展,如Y2O3、Er2O3、Al2O3等及其复合氧化物陶瓷材料,其中,因Al2O3及其复合物涂层具有优异的阻氚性能,得到了广泛的关注和研究。重点阐述了制备工艺、基体效应和辐照等影响氧化物陶瓷涂层阻氚性能的因素及氚在材料中的渗透机制,并分析了当前阻氚涂层在材料制备以及模拟服役环境等方面存在的不足与今后的研究重点,指出了未来可能的氧化物陶瓷阻氚涂层,以期为阻氚涂层的研究与后续实验提供一定的方向。     

FeAl/Al2O3阻氚层的制备新方法与性能

采用室温熔盐电镀-热处理-氧化复合新技术在HR-2不锈钢上制备FeAl/Al2O3涂层,研究热处理温度与时间的影响,并表征涂层的形貌和性能。结果表明：25 ℃下,采用AlCl3-MEIC（氯化1-甲基3-乙基咪唑）室温熔盐在HR-2钢表面获得结合良好的纯铝镀层,电沉积速率为15 μm/h。650~750 ℃热处理1~30 h, 在HR-2钢表面制得成分渐变、冶金结合、无缝隙与裂纹的3~27 μm铝化物涂层,涂层截面为3层或2层结构;涂层生长速率与热处理温度的关系符合Arrhenius公式,活化能为116.9 kJ/mol;涂层的形成过程受原子扩散过程控制,其厚度随热处理时间变化呈抛物线关系。700 ℃,4 h热处理涂层在10-2 Pa O2中继续氧化80 h后,最终涂层由约30 μm厚的FeAl扩散层及约110 nm的γ-A12O3膜组成,600 ℃下该涂层使HR-2不锈钢的氘渗透率降低3个数量级;涂层可抗750 ℃~室温冷热循环20次以上。该方法有望成为ITER中氚包容容器表面阻氚层的候选制备新方法。     

等离子喷涂氧化铝陶瓷涂层微观结构研究

采用等离子喷涂方法２１Ｃｒ－６Ｎｉ－９Ｍｎ奥氏体不锈钢表面喷涂不同成分的氧化铝陶瓷涂层,并对其微观结构进行了分析。结果表明,等离子喷涂氧化铝陶瓷涂层与基体为机械结合,涂层中存在大量气孔且元素分布不均匀,其主要相为γ－Ａｌ２Ｏ３。     

等离子喷涂氧化铝基复合涂层研究进展

随着等离子喷涂技术的发展,等离子喷涂氧化铝基复合涂层在防腐蚀、耐磨损和航天航空等领域得到了广泛应用。首先简要介绍了新型等离子喷涂技术(激光等离子喷涂、悬浮液等离子喷涂和超音速等离子等)和主要喷涂工艺参数(喷涂功率、送粉方式和喷涂距离等),然后从改善涂层耐腐蚀性能的角度出发,阐述了第二相、喷涂工艺参数和后处理工艺对涂层气孔率的影响及与涂层耐腐蚀性能的关系。重点分析了硬度、喂料特征和激光熔覆技术对氧化铝基复合涂层耐磨损性能的影响,详述了影响硬度的因素,以及喷涂粉末特征和激光熔覆处理对复合涂层微观结构的影响。在电磁波吸收性能研究方面,论述了吸收剂含量、涂层厚度和多种电磁波吸收剂匹配以及喷涂参数的调整对等离子喷涂氧化铝基复合涂层吸波性能的影响。最后对以等离子喷涂技术制备性能更加优异的氧化铝基复合涂层提出了展望。     

等离子喷涂氧化铝陶瓷涂层研究现状及展望

简述了等离子喷涂制备常规氧化铝、Al2O3-TiO2、纳米氧化铝复合涂层及梯度涂层组织和性能的相关研究成果;简述了激光重熔技术和等离子喷涂技术复合制备涂层的研究现状;在粉末成分中加入低熔点缓冲相、稀土、碳纳米管等改善涂层微观组织,增强涂层功能,探讨基于氧化铝的特殊功能涂层,并对今后发展方向作了展望.     

Development of a Pre-Oxidation Treatment to Improve the Adhesion between Thermal Barrier Coatings and NiCoCrAlY Bond Coatings

High-temperature coating systems, consisting of a René N5 superalloy, a Ni–23Co–23Cr–19Al–0.2Y (at.%) bond coating (BC), and a yttria (7 wt%)-stabilized zirconia (YSZ) thermal barrier coating (TBC), were thermally cycled to failure for seven different controlled pre-oxidation treatments and one commonly employed industrial pre-oxidation treatment to establish the preferred microstructures of the thermally-grown oxide (TGO) on a NiCoCrAlY bond coating after pre-oxidation. It was found that the failure of the coating system occurred along the TGO/BC interface when the TGO attained a critical thickness, except if a NiAl₂O₄ spinel layer developed contiguous to the TBC/TGO interface. Then, the coating system failed at a smaller TGO thickness along the NiAl₂O₄/α-Al₂O₃ interface. The value for the TGO thickness at failure increased for a larger area fraction of Y-rich oxide pegs at the TGO/BC interface after pre-oxidation. A desired slow-growing oxide layer on the BC surface was promoted when the presence of the oxides NiAl₂O₄, θ-Al₂O₃, Y₃Al₅O₁₂ at the TGO surface after pre-oxidation was avoided. The α-Al₂O₃ layer, which developed adjacent to the BC upon thermal cycling, grew at a low rate if the initial oxide at the onset of oxidation consisted of θ-Al₂O₃ instead of α-Al₂O₃. Based on these results a pre-oxidation treatment is proposed for which the lifetime of the entire coating system during service is enhanced.     

Properties of Aluminum Oxide (AlO_x) Barrier Coatings Deposited on Poly(Ethylene Terephthalate)(PET)Substrates by Reactive Magnetron Sputtering

The aluminum oxide(AlOx)coatings were deposited on poly(ethylene terephthalate)(PET)surface by reactive magnetron sputtering for improving its barrier property.With O2 flux increasing,three modes including metallic mode,transition mode and oxide mode exist in sputtering.The properties of the aluminum oxide(AlOx)coatings prepared at different modes were discussed.Also,the influences of oxygen flux on the stoichiometry,structure,gas permeation of the coatings were investigated.The chemical composition of AlOx films fabricated in transition mode is different as oxygen flux varies slightly,and the gas barrier property is better as the stoichiometry is closer to 1.5 with oxygen flux increasing.The coating uniformity,roughness and particle size depend remarkably upon oxygen flux.The coatings deposited at oxide mode have a good barrier performance to oxygen and water,and the permeability to oxygen decreases by sixty times and water vapor ten times compared with uncoated PET     

Manufacturing Process of Nanostructured Alumina Coatings by Suspension Plasma Spraying

This paper describes the formation process of nanostructured alumina coatings and the injection system obtained by suspension plasma spraying (SPS), an alternative to the atmospheric plasma spraying technique in which the material feedstock is a suspension of the nanopowder to be sprayed. The nanoscale alumina powders (d ≈ 20 nm) were dispersed in distilled water or ethanol and injected by a peristaltic pump into plasma under atmospheric conditions. Optical microscopy (OM), scanning electron microscopy (SEM), and x-ray diffraction (XRD) analyses were performed to study the microstructure of the nanostructured alumina coatings. The results showed that the nanoscale alumina powders in suspension were very easily adsorbed at the inner surface of injection, which caused the needle to jam. The rotation of the pump had a great effect on the suspension injection in the plasma. The very small resistance of the thin plasma boundary layer near the substrate can drastically decrease the impacting velocity of nanosize droplets. The concentration of suspension also has a significant influence on the distribution of the size of the droplet, the enthalpy needed for spraying suspension, and the roughness of the coating surface. The phase structures of alumina suspension coatings strongly depend on the plasma spraying distance. A significant nanostructured fine alumina coating was obtained in some areas when ethanol was used as a solvent. The microstructures of the coating were observed as a function of the solvent and the spraying parameters.     

PS-PVD制备粘结层及其对热障涂层性能的影响

目的探究真空热处理对PS-PVD制备的粘结层的影响,并研究PS-PVD制备粘结层对热障涂层性能的影响。方法采用PS-PVD技术在高温合金基体上制备不同材料体系的粘结层和陶瓷层,采用真空热处理和高温氧化试验,对粘结层与基体界面间的元素扩散过程以及不同材料粘结层对热障涂层抗氧化性能的影响进行研究,并通过X射线衍射和EDS能谱对涂层的物相及元素分布进行分析。结果通过PS-PVD制备的不同粘结层体系的热障涂层试样,在近粘结层处的陶瓷层物相组成并无明显区别。粘结层与基体的元素扩散情况受真空热处理时间和温度的影响,随着真空热处理时间的延长,基体一侧的富铝相逐渐增多。当热处理8 h后,形成的扩散区的宽度已超过20μm;随着热处理温度的提高,同样也形成了更宽的扩散区。NiCoCrAlYTa/7YSZ热障涂层氧化100h后,TGO层的厚度达到4.0μm,氧化150h时,涂层发生脱离。NiCrAlY/7YSZ热障涂层氧化150 h后,TGO层的厚度达到4.4μm,但未出现脱离现象。结论热处理的时间越长,温度越高,粘结层与基体的元素扩散行为越剧烈。不同的粘结层材料会影响热障涂层的氧化动力学过程。     

Microstructure and Tribological Behavior of Cr-Cu-N Coatings Deposited by Ion Beam Assisted Magnetron Sputtering

Cr-Cu-N coatings with copper content from 0 at%to 6.8 at%were deposited on silicon and M2 steel by ion beam assisted magnetron sputtering.The microstructure and composition of the coatings were characterized using SEM,GDOES,XRD and XPS.The mechanical properties of the coatings were tested on a standard hardness tester.The tribological behavior of the coatings in dry wear condition was studied by means of ball-on-disc wear test.The experimental results show that addition of copper can restrict the columnar crystal growing to a certain degree.XRD and XPS analysis indicate that coatings are mainly composed of Cr and CrN phase.Cu is mainly existed in a free state in the coatings.Copper adding has no obvious effects on the hardness of the coatings.However,the coatings fracture toughness can be improved by doped copper.The coefficient of friction of the coatings against bearing steel is in the range of 0.25-0.6 changing with the copper content.The coating with 2.6 at%copper shows the lowest coefficient of friction about 0.25 and wear rate which is about one tenth of that of the coating with 6.8 at%copper.The higher coefficient of friction and wear rate of the coating with 6.8at%copper may be attributed to its lower bonding strength.     

Oxidation and Degradation of EB–PVD Thermal–Barrier Coatings

Thermal–barrier coatings (TBCs) consist of a magnetron-sputtered Ni–30Cr–12Al–0.3Y (wt.%) bond coat to protect the substrate superalloy from oxidation/hot corrosion and an electron-beam physical-vapor deposited (EB–PVD) 7 wt.% yttria partially stabilized zirconia (YPSZ) top coat. The thermal cyclic life of the TBC system was assessed by furnace cycling at 1050°C. The oxidation kinetics were evaluated by thermogravimetric analysis (TGA) at 900, 1000, and 1100°C for up to 100 hr. The results showed that the weight gain of the specimens at 1100°C was the smallest in the initial 20 hr, and the oxide scale formed on the sputtered Ni–Cr–Al–Y bond coat is only Al₂O₃ at the early stage of oxidation. With aluminum depletion in the bond coat, NiO, Ni(Cr,Al)₂O₄, and other spinel formed near the bond coat. During thermal cycling, microcracks were initiated preferentially in the YPSZ top coat along columnar grain boundaries and then extended through and along the top coat. The growth stress of TGO added to the thermal stress imposed by cycling, lead to the separation at the bond coat–TGO interface. The ceramic top coat spalled with the oxide scale still adhering to the YPSZ after specimens had been cycled at 1050°C for 300 cycles. The failure mode of the EB–PVD ZrO₂–7 wt.% Y₂O₃ sputtered Ni–Cr–Al–Y thermal-barrier coating was spallation at the bond coat–TGO interface.     

热处理温度对Cr/Al涂层组织结构及性能的影响

目的提高物理气相沉积Cr/Al涂层与基材锆合金的结合强度,减少涂层表面微观缺陷及内应力。方法采用多弧离子镀及磁控溅射技术在锆合金表面溅射Cr/Al涂层,并将涂层试样分别置于600、800℃保护气氛炉中热处理30 min。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱仪(EDS)及光学显微镜(OM),分析了Cr/Al涂层热处理前后相组成、表面形貌、截面形貌、元素成分变化及涂层剪切后的剥落形貌。利用弹簧拉压试验机,测试了未处理涂层、600℃和800℃热处理涂层试样与基材锆合金的结合强度。结果 600、800℃热处理涂层相比未处理涂层,表面更加平滑,表面孔隙及微观缺陷较少,但与基材锆合金的结合强度并没有明显变化,未热处理涂层、600℃热处理涂层、800℃热处理涂层与基材锆合金的结合强度分别为44.07、44.12、44.08 MPa。结论热处理后,涂层出现Al Cr2、Al8Cr5、Al9Cr17、Al9Cr4、Al86Cr14等多种Cr-Al合金相,有利于涂层表面孔隙及大颗粒等缺陷的减少。但热处理前后,涂层与基材的结合强度未发生明显变化。     

等离子喷涂热障涂层相结构的研究

研究了等离子喷涂两层热障涂层在大气和真空环境下，经1100℃不同时间扩散处理后相结构的变化。结果表明，喷涂过程中，ZrO2发生M相→T相转变；经大气环境扩散处理后，ZrO2发生T相→M相转变，NiCrAlY相被氧化形成Al2O2和NiAl2O4相，同时r'-Ni3Al相有强烈的择优取向。     

纳米 Al2 O3 等离子喷涂涂层的制备及性能分析

目的对比研究微/纳米Al2O3等离子喷涂涂层的组织、力学及摩擦磨损行为。方法以纳米Al2O3粉末为原料,利用喷雾干燥法制备出粒径分布在35~75μm的喷涂喂料,采用等离子喷涂技术在20钢基体上制备纳米Al2O3涂层。采用商用微米Al2O3喂料,以相同的喷涂工艺制备出微米Al2O3涂层。对粉末、涂层的显微结构及涂层的磨损形貌进行表征,对比分析两种涂层的组织、力学性能和摩擦磨损行为。结果与微米Al2O3涂层相比,纳米Al2O3涂层粒子间结合更为致密,使得其结合强度和显微硬度得到大幅度提高。在载荷750 g,转速1000 r/min的条件下,微米Al2O3涂层的摩擦系数为0.41,而纳米Al2O3涂层仅为0.34,并且摩擦系数值的波动幅度更为稳定。在不同转速下,纳米Al2O3涂层的磨损率均降低明显。结论纳米Al2O3等离子喷涂涂层组织致密,表现出了较好的力学性能和耐磨性。