14nm低原子序数材料多层膜的设计和制备

为了减小常规多层膜的带宽,提高其光谱分辨率,对采用低原子序数材料组成的适用于极紫外和软X射线波段的多层膜进行了研究.首先,在14 nm波长处选取3种低原子序数材料对Si/B4C,Si/C和Si/SiC组成多层膜,用随机搜索的方法优化设计了这3种多层膜以及在此波段常用的Mo/Si多层膜.然后,用直流磁控溅射的方法制备Si...     

真空紫外波段Al膜保护层MgF_2的光学常数

由于Al膜的保护层MgF_2薄膜的光学常数对Al/MgF_2高反射镜的性能有极大的影响,本文研究了获取MgF_2薄膜光学常数的方法。用热舟蒸发的方法在室温B270基底上镀制了3块不同MgF_2厚度的Al/MgF_2反射镜样品,通过掠入射X射线小角反射方法表征样品,获得了膜层厚度和粗糙度。在国家同步辐射实验中心计量站测试了入射角为5°时,样品在105~130nm波段的反射率。在Al、MgF_2膜层的厚度和Al的光学常数已知条件下,依据菲涅尔公式,得出了满足某波长处样品反射率的等值曲线,然后从三条曲线的交点得出了MgF_2薄膜在108~128nm波段的光学常数。对比和分析显示:利用此方法得到的108~128nm波段MgF_2薄膜光学常数计算的反射率曲线和实际测试得到的反射率曲线吻合较好。     

非极化中子超镜用NiC薄膜制作技术研究

NiC/Ti中子超镜是一种高性能的中子多层膜光学元件,NiC纳米薄膜的制作是实现NiC/Ti多层膜的关键技术。基于Ni和C的直流磁控溅射方法,提出了一种NiC联合溅射靶材的实现方法,并制作了NiC单层膜样品。X射线光电子能谱的测量结果表明:用联合溅射靶材制作的NiC薄膜中Ni和C的原子数比与理论预期相吻合;基于X射线光电子能谱测试得到的Ni、C原子数比,通过构建Ni_(86)C_(14)的模型,可以很好地对掠入射X射线反射测试结果进行理论拟合。该研究可为进一步开展NiC/Ti中子超镜的制作提供参考。     

软X射线共振反射方法表征Sc/Si多层膜界面化合物成分的计算研究

Sc/Si周期多层膜是极紫外波段的重要材料,但膜层界面处材料原子间的扩散与化合反应严重影响了多层膜反射率。为了无损表征多层膜界面化合物的成分,利用软X射线共振反射的方法,研究了Sc/Si多层膜界面化合物成分。在Si的L吸收边附近,计算了不同周期厚度以及不同界面硅化物成分的Sc/Si多层膜的共振反射率。结果表明,界面硅化物成分不同的膜系在Si的L边处的反射率有明显差异,并且反射率随着膜层中Si化合反应的消耗而降低,证实了软X射线共振反射方法在亚纳米尺度下对化合物的成分进行无损分析的可行性,为后续的实验研究提供参考。     

软X射线多层膜反射镜的设计、制备与检测

本文提出一种图像直观、结果可靠的软X线多层膜设计方法,讨论了与软X射线多层膜制备有关的基板选择,膜厚控制等工艺问题。给出Mo/Si软X射线多层膜小角度衍射及171Å、231Å及256Å处软X射线反射率的测试结果,并对软X射线多层膜工作做了展望。     

真空度对Ni80Cr20薄膜中性度的影响

理论计算了Ni、Cr和Ni80Cr20三种材料的光学特性,确定了镍铬成份变化对Ni80Cr20的影响。在高低两个真空度条件下采用电子枪蒸发工艺进行了Ni80Cr20的镀膜实验,结果表明,低真空度时"薄"膜的中性度较好,而高真空度时"厚"膜中性度较好。采用X射线能谱分析发现"薄"膜铬含量高于膜料,而"厚"膜更高,高真空度薄膜略有氧化,而低真空度氧化更严重。从残余气体和蒸发方式方面分析了镍铬成份差异的原因,再结合氧化对薄膜特性的影响,确定了不同真空度薄膜中性度差异的原因。     

极紫外Mg/SiC、Mg/Co多层膜的稳定性

采用磁控溅射法在Si(100)基底上镀制了膜系结构分别为[Mg/Co]20、[Mg/SiC]20的两组多层膜,以研究Mg基多层膜的稳定性.对放置在室温和80％相对湿度环境下的样品进行显微镜、表面粗糙度和X射线掠入射反射率测试,对比研究了Mg/Co和Mg/SiC两种多层膜结构在相同环境中的损坏状况.对比结果显示:放置4天后,Mg/SiC损坏面积为26.34％,表面粗糙度为10 nm; Mg/Co的损坏面积为2.78％,表面粗糙度为5 nm.6天后,X射线掠入射反射率测量显示Mg/SiC多层膜一级反射峰完全消失,而Mg/Co多层膜的一级反射峰仍有47.63％的反射率.实验表明,Mg/Co多层膜的表面层和内部多层膜结构的损坏速度较Mg/SiC慢,具有较好的环境稳定性.另外,X射线光电子谱(XPS)测试Mg基多层膜损坏后的产物主要为MgCO3、Mg(OH)2和少量的MgO,且内层Mg(OH)2与MgCO3含量的比值显著高于表面层.分析认为,水汽是造成Mg基多层膜损坏的主要原因,今后Mg基多层膜保护层的研究可主要针对如何防止水汽进入膜层.     

阴极电弧源镀制TiO2薄膜的研究

在真空条件下利用阴极电弧源在不同基底材料上镀制TiO2薄膜.对影响镀膜过程和膜层质量的氧气工作压强、偏压和电流等因素进行研究.经X射线结构分析结果显示TiO2薄膜主要以锐钛矿结构为主及少量的金红石结构.对TiO2薄膜的化学性质、力学性质进行了初步检测.     

类镍钽软X射线激光用多层膜反射镜的研制

设计并制备了工作波长为4.48 nm类镍钽软X射线激光用多层膜反射镜。选择C r/C、C r/Sc为多层膜材料对,模拟了多层膜非理想界面对多层膜反射率的影响。采用直流磁控溅射技术在超光滑硅基片上制备了C r/C、C r/Sc多层膜。利用X射线衍射仪测量了多层膜结构,在德国Bessy II同步辐射上测量了多层膜的反射率,C r/C,C r/Sc多层膜峰值反射率分别为7.50%,6.12%。     

用透射光栅谱仪测量多层膜的反射特性

软X射线多层膜是当前应用光学和工程光学的研究热点之一,反射率是其性能和膜层质量最直观的参数,它的测量对了解多层膜性能和改进多层膜制备工艺具有重要意义。本文介绍采用带有前置光学系统的大面积透射光栅光谱仪分光,让软X射线多层膜反射+1级或-1级软X射线,用国产的SIOFM型X射线胶片接受软X射线,通过测量可定性地判断多层膜制备质量,为改进多层膜制备工艺提供重要的参考依据。     

A method for the tribological testing of thin,hard coatings

A new method has been developed for tribological testing of thin, hard antiwear coatings, using a ball‐on‐disc tribosystem, under conditions of dry sliding. In this, an Al₂O₃ ball is pressed against a coated steel disc. Wear debris is removed from the contact zone by a stream of dry argon in this novel method. This improves the stability of the tribological properties and the repeatability of the test results. All test conditions are precisely defined, in particular: the type of motion, air relative humidity, ambient temperature, sliding speed, load, tribosystem spatial configuration, substrate material, substrate hardness and roughness, and coating thickness. The method developed has been used to test various physical vapour deposition coatings (deposited by the vacuum arc method), i. e., single‐layer TiN, Ti(C,N), CrN, and Cr(C,N), and multilayer Cr(C,N)/CrN/Cr and Cr(C,N)/(CrN+Cr₂N)/CrN/Cr. It is shown that CrN coatings exhibit the best antiwear properties, and Ti(C,N) the worst. Friction coefficients for CrN and Cr(C,N) coatings are much lower than for the more commonly used TiN. Multilayer coatings have better antiwear properties than single‐layer ones.     

A comparative study on the structure and hardness enhancement of a-BON/nc-TiN films prepared by low and high RF frequency PAMOCVD

Amorphous (a)-BON/nanocrystal (nc)-TiN bilayer coatings were deposited on a p-type silicon(1 0 0) substrate by low and high RF frequency plasma-assisted metal–organic chemical vapor deposition(PAMOCVD) system, using tetrakisdimethylaminotitanium(TDMAT, [(CH₃)₂N]₄Ti) and trimethylborate(TMB, (CH₃O)₃B) as TiN and BON precursors, respectively. We used Ar gas as a plasma source and N₂ gas as a reactive and additional nitrogen source. In this study, we have mainly investigated the relationship between the hardness and the structure of the coating layers by the effects of deposition parameters such as frequency, deposition time and substrate temperature. The results show that the surface structure of the top layer and the interface structure of layer-by-layer affect the hardness enhancement in bilayered a-BON/nc-TiN thin films. The as-grown films were characterized using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), atomic force microscope (AFM), scanning electron microscope (SEM) and nano indenter.     

Advances and problems with TEM characterization of Cr/CrN multilayer coatings

Multilayer Cr/CrN/Cr/Cr(N,C) and Cr/CrN with 8 and 32 layer coatings were deposited on austenite substrates using pulsed laser deposition (PLD) technique. The microstructure observations were performed using Philips CM20?, TECNAI G² F20 – TWIN? and JEOL EX4000? transmission microscopes. The performed experiments indicated that lowering the argon flow from 60 to 30 cm³/s during chromium ablation changes buffer layers microstructure from nearly amorphous to nano‐crystalline. The nitride or carbo‐nitride layers turned out to be less sensitive to changes in nitrogen flow during deposition. The columnar microstructure of Cr layers is coarser than those in CrN ones under the same deposition condition. This observation proved also that relying on PLD technique as thin as 30 nm layers might be formed within multilayer Cr/CrN coatings.     

Investigation of antiwear coatings deposited by the pvd process

The tribological properties of various PVD‐deposited coatings (vacuum arc method) have been tested, both single‐layer coatings (TiN, CrN, Ti(C,N), and Cr(C,N)) and multilayer coatings (Cr(C,N)/CrN/Cr and CR(C,N)/(CrN+Cr₂N)/CrN/Cr). An unlubricated ball‐on‐disc tribosystem was used in which an Al₂O₃ ball is pressed against a coated steel disc rotating in the horizontal plane. A novelty of the method is the removal of wear debris from the contact zone using a draught of dry argon. This improves the repeatability of the test results and the stability of the tribological characteristics. It is shown that CrN coatings exhibit the best antiwear properties and Ti(C,N) the worst. Multilayer coatings have better antiwear properties than single‐layer ones. The friction coefficients for CrN and Cr(C,N) coatings are much smaller than for the commonly used TiN. A correlation has also been found between the physical properties of the coatings tested (adhesion of the coating to the substrate assessed in scratch tests, and coating hardness) and their antiwear properties. An improvement in coating‐substrate adhesion results in wear reduction, while greater hardness (causing a coating embrittlement increase and a change in the wear mechanism) brings about greater wear. There is no correlation between the physical properties and the friction coefficients of the coatings tested.     

Microstructure and Magnetic Properties of Sputtered Co5 Sm Films

Co5Sm/Cr bilayer films were deposited on Si and glass slides by means of a Direct-Current(DC)magnetron sputtering system with substrate heating.Magnetic properties measurements show that the sample with glass substrate has a comparatively large coercivity(Hc=2 141.2 Oe)with a relatively low optimal temperature(Ts=350 ℃).X-ray diffraction patterns indicate that Cr presents a hexagonal-close-packed(hcp)texture on Si,while a body-centered-cubic(bcc)structure on glass substrate,which leads to Co5Sm films having different lattice constants on Si and glass substrates.At their optimal temperature,the grain size of the sample on glass slide is smaller with its size distribution more uniform.Concurrently,the shape of magnetic domain is more regular and ordered.The value of magnetic switching volume(V)for the film on glass is 1.65×10-18 cm3,smaller than that for films on Si.For the film on glass,the magnetization reversal mechanism is mainly influenced by magnetocrystalline anisotropy,the shape of the crystal grain and the stress in the film.     

2Cr13不锈钢表面电火花强化及磨损和冲蚀行为研究

采用电火花表面沉积(ESD)技术,选用YG-8硬质合金和石墨两种电极,对2Cr13不锈钢进行表面强化处理。研究了强化层深度的影响因素,采用辉光放电谱仪(GDS)测试强化层元素分布,用X射线衍射仪(XRD)分析组织结构,用球盘磨损试验机评价耐磨性能,用喷砂型冲蚀装置评价冲蚀性能。结果表明:强化层与基体为冶金结合,其深度随电源电压增加而增大,Ar气保护能有效地降低强化层中N、O含量。石墨电极强化层存在大量的Fe3C、奥氏体和少量石墨;硬质合金电极强化层存在大量的W2C、Co6W6C和WC1-x。经YG-8和C电极强化后,2Cr13不锈钢表面的硬度大幅度提高,摩擦系数明显降低,粘着磨损得到有效的控制,耐磨性能得到显著的改善。在10°小冲蚀角条件下,强化层明显提高了基体的抗石英砂冲蚀性能,而90°垂直冲蚀时,强化层的抗冲蚀性能却不及基体,原因是强化层韧性不及基材。     

爆炸喷涂Cr_3C_2-NiCr涂层及其对2Cr10MoVNbN钢疲劳性能的影响

采用爆炸喷涂方法在2Cr10MoVNbN钢基体表面制备了Cr3C2-NiCr涂层,利用光学显微镜、扫描电镜、X射线衍射仪、能谱仪、显微硬度计、电子拉伸试验机、X射线应力仪、疲劳试验机等分析测试了涂层的缺陷、显微硬度、断裂韧度、结合力、残余应力、疲劳性能等,主要研究了涂层对基体疲劳性能的影响.结果表明:在2Cr10MoVNbN钢基体上采用爆炸喷涂方法制备的Cr3C2-NiCr涂层的孔隙率为0.5%,表面硬度为921 HV,断裂韧度为3.67 Mpa·m1/2,涂层与基体的结合强度为63 Mpa,涂层表面、涂层/基体界面处均处于压应力状态;爆炸喷涂Cr3C3-NiCr涂层明显降低了2Cr10MoVNbN钢基体的疲劳性能,在应力幅小于500 Mpa时,与基体试样相比,涂层试样的疲劳寿命减少了75%以上,疲劳强度下降了134.7 Mpa,涂层试样的疲劳裂纹源出现在涂层/基体界面的Al2O3夹杂物处.     

Structural and mechanical properties of (Cr,Ni) N single and gradient layer coatings deposited on mild steel by magnetron sputtering

Ternary single and gradient layer (Cr, Ni) N thin films were deposited on the mild steel substrate by unbalanced magnetron sputtering technique in order to evaluate mechanical properties for machine tools and automotive applications. Microstructure, chemical composition, surface morphology and phase analysis were carried out using field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, atomic force microscopy and X-ray diffraction, respectively. Both single and gradient layer of (Cr, Ni) N coatings show a significant increment in mechanical properties such as hardness, adhesion strength and surface roughness along with the reduction of friction coefficient. Mechanical tests revealed that the hardness of the gradient layer increased up to 3.1 times due to the formation of Cr₂N and Ni phase whereas single layer showed the least friction. Single layer CrNiN layer exhibited 27.2% less surface roughness (R_a) in comparison with gradient layer. High values of surface roughness, hardness, thickness and friction could be correlated with high film-to-substrate adhesion (L_c2) for the gradient layer.