注入氮离子的SiC涂层阻氢性能研究

利用离子束混合－离子注入（Ar^ ）和磁控溅射相结合的实验技术在HR－1不锈钢基体上制备了注入N^ 的SiC涂层，并用表面分析手段对所制备涂层的表面形貌，剖面形貌、相结构，表面成分，表面元素的化学态进行了分析，结果表明：制备的涂层结构致密，表面平整、膜层成分均匀；涂层与基体之间形成了一明显的过渡层，增强了涂层和基体之间的结合力，用二次离子质谱（SIMS）对充氘涂层的阻氢性能进行了定性分析，结果表明，涂层元素与氢形成稳定的化学键，抑制了氢的扩散和迁移，使得涂层具有一定的阻氢能力。     

不锈钢表面涂覆C-SiC涂层及其阻氢性能的研究

采用磁控溅射结合离子束混合技术在不锈钢基体上制备C-(50～90)％ SiC涂层,对涂层进行加热处理及氢离子注入.对各种条件下制备的涂层进行元素深度分布分析.结果表明,SiC组分含量高的涂层具有更好的阻氢性能,而C组分含量高的涂层与基体具有更好的结合性能,综合考虑今后在氚废物包装桶涂覆的实际使用工况来看,采用C-(75～85)％SiC作为涂层似乎更合适些.通过对涂层阻氢性能的分析发现,C-SiC涂层经加热处理后,涂层的阻氢能力得到进一步的提高,并且可以提高氢离子在涂层中的稳定性.     

HL—1装置中的TiC涂层辐照实验研究

利用ＨＬ－１装置的等离子体辐照研究了石墨基体上的ＴｉＣ涂层。对辐照前、后 的样品进行了俄歇电子能谱（ＡＥＳ）、扫描电镜（ＳＥＭ）和Ｘ射线衍射谱（ＸＤＳ）分析，得 出：ＴｉＣ涂层内Ｔｉ、Ｃ分布比较均匀；在高功率托卡马克放电辐照下，化学腐蚀现象 较为严重，但没有改变ＴｉＣ结构相（立方ＴｉＣ）；并有一定的择优取向。同时还发现 Ｃ的优先溅射作用及 Ｔｉ向石墨基体深层扩展现象。     

溶胶-凝胶法制备金属基铝硅酸盐陶瓷涂层

采用溶胶－凝胶法,在不锈钢基体上制备铝硅酸盐陶瓷涂层,对涂层微观结构进行了分析,研究了涂层化学组成、涂最度对抗热震性、抗氧化性的影响,结果表明：涂氢化学组成为３Ａｌ２Ｏ３．２ＳｉＯ２、厚度２μｍ时,制备的涂层材料与基体结合紧密、显微结构致密均匀,有良好的抗热震、抗氧化性能。     

搪瓷涂层对316L不锈钢表面润湿性的研究

为进一步降低316L不锈钢在核反应堆中使用过程中氢和氢同位素渗透所导致的危害，欲通过制备致密的与基体结合良好的搪瓷涂层进行保护，介绍了涂层的制备过程。涂层的质量及其保护效应与涂层高温熔体对基体的润湿性能有密切的关系，本试验通过不同方式往搪瓷釉浆中加入一定量的低表面能氧化物A，结果表明涂层高温熔体对不锈钢基体的润湿性能得到不同程度的改善，且作为玻璃组份直接加入比后续磨加的效果要好。     

用气相反应法制备C/C复合材料的梯度SiC涂层

本文采用化学气相反应法（CVR）制备了C/C复合材料的梯度SiC涂层,对该梯度涂层的形成机理及抗氧化性能进行了试验研究.研究结果表明：Si渗入基体的速率对梯度涂层的形成产生直接的影响,当采用体密度较高的C/C基体时,得到了完整致密的梯度SiC涂层,生成的SiC为β-SiC,该涂层具有较好的高温抗氧化能力,在1500℃静态空气气氛中,氧化26小时后失重不超过2%.     

电泳沉积-烧结制备石墨材料SiC涂层的研究

采用电泳沉积法在石墨基体上制备厚度可控的Si涂层,考察了电泳沉积参数(电压、沉积时间、固含量及添加剂量)对涂层沉积量的影响.所制备的Si涂层通过烧结与石墨基体发生在位反应形成SiC涂层.用SEM观察涂层烧结前后的形貌,发现烧结后Si渗入基体内部.孔径分布数据表明所形成的SiC涂层导致石墨孔径变小.实验提供了一种制备SiC涂层的新方法,电泳沉积一烧结可用于C/SiC复合材料的制备.     

304不锈钢激光熔覆Co-Ti3SiC2自润滑复合涂层微观组织与摩擦学性能

采用激光熔覆同步送粉法在304不锈钢上制备出自润滑耐磨涂层,熔覆粉末配比为纯Co,Co-2％Ti3 SiC2(质量分数,下同)和Co-8％Ti3 SiC2.借助扫描电子显微镜(SEM),能谱分析仪(EDS)和X射线衍射仪(XRD)对熔覆涂层进行表征,系统地研究304不锈钢与涂层在室温和600℃下的摩擦学性能与磨损机理.结果表明:激光熔覆Co-Ti3 SiC2涂层的平均显微硬度高于基体(240.3HV0.5),N1,N2和N3涂层的硬度分别为285.7HV0.5,356.3HV0.5和463.8HV0.5,涂层主要由连续基体γ-Co固溶体,硬质相Fe2 C,Cr7 C3和TiC,润滑相Ti3 SiC2组成.在室温下,基体和N1,N2,N3涂层的摩擦因数分别为0.56,0.62,0.68和0.42,N1,N2,N3三种涂层的磨损率分别为9.15×10-5,7.81×10-5,4.66×10-5 mm3/(N·m),均明显低于基体(66.42×10-5 mm3/(N·m));在高温下,基体和N1,N2,N3涂层的摩擦因数为0.66,0.54,0.52和0.46,N1,N2,N3三种涂层磨损率分别为37.79×10-5,35.6×10-5,18.83×10-5 mm3/(N·m),均低于基体(41.3×10-5 mm3/(N·m)).在室温和600℃下,涂层具有高于304不锈钢基体的显微硬度,且Co-8％Ti3 SiC2涂层呈现出最好的自润滑耐磨性能.     

涂层材料的断裂分析

和基体厚度相比，涂层很薄，因此细观力学模型可把基体作为半无限弹性体，由于涂层和基体材料的膨胀系数及弹性系数不匹配，涂层材料中残余热应力的解析解为Ｅｃ／（１－ｙｃ）·（αｓ－αｃ）△Ｔ。用有限元法校核，该应力和解析解吻合得好，通过对涂层产生裂纹驱动力和断裂韧性的讨论，提出了抗裂涂层厚度公式。     

C-90%SiC涂层加热处理前后形貌特征及其阻氢性能的研究

对离子束混合技术在不锈钢基体上沉积C-90%SiC涂层进行不同温度的加热处理及H+注入.对加热处理前后H+注入涂层表面进行了SEM的观察,研究涂层表面加热处理前后鼓泡数量及分布的变化.通过AFM分析,研究涂层内沉积颗粒大小、形状以及分布与加热处理温度的关系.通过SEM-EDAX测量,研究涂层内组元分布的变化.涂层的H+注入的二次离子深度分布测量表明,试样经加热处理后,涂层的阻氢能力得到进一步的提高.     

Microanalyses on the hydrogen permeated 70% SiCC films

SiCC films with content of 70% SiC were deposited by rf magnetron sputtering on stainless steel or NaCl substrate followed by argon ion bombardment. Samples were then submitted to hydrogen permeation at 3.23×10⁷ Pa and 500 K for 3 h. Secondary ion mass spectroscopy (SIMS) was used to analyze hydrogen concentration with depth and to check the formation of hydrogen related bonds in the SiCC films with IR measurement. Auger electron spectra (AES) and X-ray photoelectron spectra (XPS) were carried out to check the effects of hydrogen participation on shifts of chemical bonding states of C, Si and O contamination.     

Microanalysis on the Hydrogen Ion Irradiated 50 wt pct TiC-C Films

The 50 wt pct TiC-C films were prepared on stainless steel substrates by using a technique of ion beam mixing. These films were irradiated by hydrogen ion beam with a dose of 1×10^18 ions/cm^2 and an energy of 5 keV. Microanalysis of X-ray photoelectron spectroscopy （XPS） and secondary ion mass spectroscopy （SIMS） were used to analyze the films before and after hydrogen ion irradiation and to study the mechanism of hydrogen resistance.     

Effect of heating on the behaviors of hydrogen in C-TiC films with auger electron spectroscopy and secondary ion mass spectroscopy analyses

C-TiC films with a content of 75% TiC were prepared with magnetron sputtering deposition followed by Ar⁺ ion bombardment. Effect of heating on the behaviors of hydrogen in C-TiC films before and after heating was studied with Auger Electron Spectroscopy and Secondary Ion Mass Spectroscopy (SIMS) analyses. SIMS depth profiles of hydrogen after H⁺ ion implantation and thermal treatment show different hydrogen concentrations in C-TiC coatings and stainless steel. SIMS measurements show the existence of TiH, TiH₂, CH₃, CH₄, C₂H₂ bonds in the films after H⁺ ion irradiation and the changes in the Ti LMM, Ti LMV and C KLL Auger line shape reveal that they have a good hydrogen retention ability after heating up to the temperature 393 K. All the results show that C-TiC coatings can be used as a hydrogen retainer or hydrogen permeable barrier on stainless steel to protect it from hydrogen brittleness.     

Highly sensitive detection of net hydrogen charged into austenitic stainless steel with secondary ion mass spectrometry

Secondary ion mass spectrometry (SIMS) is used to detect local distributions of hydrogen in various materials. However, it has been well-known that it is extremely difficult to analyze net hydrogen (H(N)) in metals with SIMS. This was because hydrogen, which is originated from moisture (H(2)O), hydrocarbon (C(x)H(y)) or other organic materials (C(x)H(y)O(z)) existing on a sample surface or in the SIMS chamber, is simultaneously detected in the SIMS measurement of the H(N), and the H(N) and the background-originated hydrogen (H(BG)) cannot be distinguished in a SIMS profile. The effective method for reductions and determinations of the H(BG) in hydrogen measurements of metallic materials with the SIMS method has not been established. The present paper shows an effective method for reduction and estimation of H(BG) in SIMS analyses of hydrogen charged into type 316 L austenitic stainless steel, and an accurate estimation method of the net charged hydrogen. In this research, a silicon wafer is sputtered by a primary ion beam of a SIMS near an analyzed area (silicon sputtering method) to reduce H(BG). An uncharged type 316 L sample was prepared for estimation of H(BG) in SIMS measurements of the hydrogen-charged sample. The gross intensities of hydrogen between the hydrogen-charged sample and the uncharged sample were compared. The gross intensities of hydrogen of the uncharged sample (26.8-74.5 cps) were much lower than the minimal gross intensities of hydrogen of the hydrogen-charged sample (462-1140 cps). Thus, we could reduce the H(BG) enough to estimate the hydrogen charged into the type 316 L sample. Moreover, we developed a method to determine intensities of H(BG) in the measurement of the hydrogen-charged sample by estimating the time-variation of hydrogen intensities in the measurements of the uncharged sample. The intensities of the charged hydrogen can be obtained by subtracting the estimated intensities of the H(BG) from the gross intensities of hydrogen of the hydrogen-charged sample. The silicon sputtering method used to reduce H(BG) and the determination method for H(BG) in this research can be applied to the accurate hydrogen analysis for other various metallic materials.     

Boron and aluminum diffusion into 4H-SiC substrates

Boron and aluminum doping by diffusion into n-type 4H-SiC Si-face substrates was carried out at the temperatures of 1800-2000 °C. Secondary ion mass spectroscopy (SIMS) was employed to obtain the impurity profiles, which showed that linearly graded boron profile and shallow aluminum profiles have been achieved, which may be a promising application in SiC device fabrication, such as p-n diode or ohmic contact. Characterization of high temperature processing influence on SiC surface morphology has been performed. Elemental boron and aluminum carbide were determined to be the best candidates as an impurity source materials for realizing p-type diffusion.     

Fabrication and characterization of bioactive glass coatings produced by the ion beam sputter deposition technique

Ion beam sputtering and ion beam sputtering/mixing deposition techniques were used to produce thin bioactive glass coatings on titanium substrate. It was found that as-deposited coatings were amorphous. Scanning electron microscopical examination showed that the coatings had a uniform and dense structure and that fabrication parameters affected the surface morphology of the coatings. The surface Ca/P ratio of the coatings, which varied from 5.9 to 8.6 according to semi-quantitative EDX analyses, was correlated with the fabrication condition. Depth profiling of the coatings revealed four distinct zones: the top surface, the thin coating zone, the intermixed zone of coating and substrate, and the substrate. Scratch tests showed that the coatings adhered well to the substrate.     

Auger electron spectroscopy and secondary ion mass spectrometry depth profiling with sample rotation

Recently, there has been a rapid increase in the application of multilayered structured materials, as opposed to bulk materials, in many areas of technological development. Accurate characterization of the structure and composition of advanced multilayers such as superlattices, quantum wells, contacts, and coatings is important for materials and device fabrication technology. Surface analysis techniques including Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy, and secondary ion mass spectrometry (SIMS) in conjunction with ion beam sputtering (sputter depth profiling) are at present the most widely used methods for characterization of modern multilayer thin film materials and devices. Ion-beam-induced surface topography, however, can limit depth resolution, and with SIMS, can also cause changes in the secondary ion yield. These changes are due to the high sensitivity of secondary ion yield to the local angle of incidence on sputter-roughened surfaces. Degradation of depth resolution and changes in secondary ion yields during sputter depth profiling have often limited studies of thin film interdiffusion, segregation, oxidation at interfaces, and impurity effects. Much theoretical and experimental work has been carried out to try to improve depth resolution including the use of low ion beam energy, high angle of incidence, and two ion guns. Recent studies of AES and SIMS with sample rotation have shown that depth resolution can be improved substantially and that constant secondary ion yields in SIMS can be achieved. We will first provide an overview of the studies made by various groups to improve depth resolution of metal multilayers using AES with rotation. Next we will review recent investigations of SIMS using sample rotation including studies of the effects of sample rotation on O₂⁺ ion-beam-induced topography, secondary ion yield, and the depth resolution of electronic, metallurgical and dielectric materials. The results presented demonstrate that SIMS with sample rotation provides constant secondary ion yield, and depth-independent depth resolution because sample rotation prevents ion-beam-induced roughness and reduces the effect of the inhomogeneity of low energy ion beams.     

Y_2Si_2O_7晶须增强MoSi_2复合涂层的制备及性能

采用水热电泳沉积法在C/C-SiC复合材料表面制备了Y2Si2O7晶须增强MoSi2复合抗氧化外涂层。采用X射线衍射仪(XRD)和扫描电子显微镜(SEM)对涂层的相组成和显微结构进行了表征。研究了Y2Si2O7晶须对复合涂层显微结构和抗氧化性能的影响。结果表明:Y2Si2O7晶须对复合涂层的显微结构和抗氧化性能有较大的影响。与MoSi2/SiC涂层相比,Y2Si2O7-MoSi2/SiC复合涂层均匀、致密,无显微裂纹。在静态空气氧化过程中,Y2Si2O7晶须有效阻止了外涂层的开裂,提高了涂层的抗氧化性能。该复合涂层试样在1773 K下氧化100 h,失重仅为0.73%,相应的失重速率仅为1.48×10-5g.cm-2.h-1。     

Morphological, structural and optical properties of thin SiC layer growth onto silicon by pulsed laser deposition

Crystalline silicon carbide thin layers were grown on a p-type Si(1 0 0) substrate by pulsed laser deposition (PLD) using KrF excimer laser at λ=248 nm from a 6H-SiC hot-pressed target. The target “SiC” used to elaborate our SiC films is realized from a mixture of 1SiO₂ with 3C (carbon) “1SiO₂+3C” heated in an oven at 2500 °C (the target was a hot-pressed material and supplied by Goodfellow). The morphological, structural and optical properties of SiC layers were investigated by scanning electronic microscopy (SEM), high-resolution X-ray diffraction (XRD), secondary ion mass spectrometry (SIMS) and UV-visible spectrophotometer. XRD analysis of the target showed that this latter is a hexagonal structure (6H-SiC). The XRD pattern shows that a 1.6 μm crystalline SiC layer was formed. In addition, a SIMS analysis gives a ratio Si/C of the thin SiC layer around 1.15 but the ratio Si/C of the target was found equal to 1.06, whereas one should have 1.0. This is due to the degree of the sensitivity of the SIMS technique and due to the higher ionization efficiency of Si compared to C atoms, all these which give different ratios. It is known that the PLD technique reproduces the same macroscopic property (optical, mechanical, structural, etc.) of the target. An optical gap (E_Gap) of the SiC layer of about 2.51 eV was obtained by reflectance measurement. Finally, a crystalline thin SiC layer of 1.6 μm was elaborated using PLD method at low-temperature deposition.