Ni80Cr20薄膜的光谱中性度优化

金属材料薄膜的光学常数会随膜层厚度发生变化,从而导致薄膜的光谱特性也发生变化。在制备工艺中,不论是热蒸发工艺还是溅射工艺,Ni80Cr20（简称镍铬）薄膜在较“薄”和较“厚”的时候光谱中性度都较差,并且其光谱特性趋势相反。理论计算结果表明,增加镍铬合金中Cr（铬）的比份可以提高“薄”膜的中性度,而“厚”膜则需要提高Ni（镍）的比份。针对光谱特性相反的“薄”膜和“厚”膜,分别提出了“有意分馏”和增加镍的比例的方法来改善光谱的中性度。试验结果表明：为改善膜层的中性度,低密度时可采用“有意分馏”的热蒸发工艺来提高膜层中铬的含量;而高密度时则可以镀制纯镍。“有意分馏”的热蒸发工艺可将光谱中性度提升至1.8%;纯镍工艺可将OD4的光谱中性度提升至4.6%。所提出的改进的镀膜工艺是有效的,并为光谱检测、光纤通讯、摄影摄像等应用领域的衰减片制备工艺的改进提供了参考。     

一种基于Ni80Cr20薄膜的高精度中性密度滤光片的制备方法

Ni80Cr20合金薄膜在可见光波段展现出很好的光学中性度。真空镀膜系统中石英晶振膜厚传感器的测量误差是导致薄膜的实际光密度值偏离设定值的主要原因。为此,提出了一种提高中性密度滤光片光密度值精度的制备方法,即采用真空镀膜结合离子束蚀刻技术,通过对镀膜和蚀刻参数的精确控制,实现对薄膜厚度的精密调控,将光密度值的相对误差控制在±2%以内,绝对误差不超过±0.01,使得薄膜的厚度调控量处于原子层尺度,满足了滤光片在高精度要求下光谱系统中的使用要求。同时验证了中性密度滤光片在离子束蚀刻微量减薄后,依旧拥有良好的光学性能和表面平整度,使得离子束轰击蚀刻薄膜技术成为一种新的且可靠的薄膜厚度微量调控方法。     

用X射线反射测量法表征双层结构中 低原子序数材料的特性

介绍了用X射线反射测量术表征双层薄膜中低原子序数材料特性的方法。由于低原子序数材料的光学常数与Si基板材料的光学常数非常接近,用X射线反射法确定镀制在Si基板上的低原子序数材料膜层结构的变化十分困难,因此,提出了在镀制低原子序数材料前,首先在基板上镀制一层非常薄的金属层的方法。实验中,选用Cr作为金属层材料,制备并测试了三种不同C膜镀制时间的Cr/C双层薄膜。反射率曲线拟合结果表明,C膜密度约为2.25 g/cm³,沉积速率为0.058 nm/s。     

柔性透明薄膜掺杂微纳米粒子的光谱特性研究

柔性材料因杨氏模量较小,在外力作用下易变形而受到广泛研究和应用。聚二甲基硅氧烷(PDMS)是一种高分子聚合物,并且具有光学透明、化学惰性等特点。Ni在0.3~2μm具有高吸收性,Al_2O_3在0.4~0.8μm具有高反射性。提出将微纳米Ni或Al_2O_3粒子掺杂到PDMS薄膜中的结构,先利用米氏散射理论计算出单个粒子的辐射特性,再利用蒙特卡洛方法求解整个模型的辐射特性。研究发现,薄膜模型的光谱特性受粒径影响:当波长不变时,掺杂Ni粒子的模型的吸收率与粒子浓度和膜厚成正比;掺杂Al_2O_3粒子的模型的反射率与粒子浓度和膜厚成正比;2种模型的透射率均与粒子浓度和膜厚成反比。最后根据布格尔定律推出的关系式证明了光谱特性变化的机理。     

一种45°直头外圆车刀薄膜测力传感器的设计与研究

设计了一种45°直头外圆车刀薄膜测力传感器,该传感器是由45钢基片、Al2O3薄膜及镍铬薄膜(Ni80%Cr20)电阻栅溅射沉积形成,然后通过低温低压扩散焊接技术焊接在车刀刀杆的设定位置,镍铬薄膜电阻栅与导线连接组成惠斯通电桥可获得较好的输出电压。对电桥输出电压与梁的受力变形关系及传感器受到各向分力关系进行了分析。分析结果表明:只需在45°直头外圆车刀刀杆的4个侧面安装传感器即可实现三向力的测量,该方法大大减小了传感器的尺寸,简单可行,并且精确度高,减少研究成本、缩短开发周期。     

金属表面色的计算机色度分析探讨

对通过固体介质热氧化着色法处理的 1Cr18Ni9Ti奥氏体不锈钢的表面颜色进行计算机色度分析 ,结合色度学的原理对氧化膜表面色的主干波长、虚拟光谱及膜厚评估的计算机实现方法加以讨论     

新的金属粉末—氢化钙共还原高合金钢与合金粉的性质

国内外用来制造高合金钢和合金粉只有惰性气体雾化法已用于工业生产。但是,用雾化法制造的含铬、铝、钛等的合金粉末,其颗粒表面总是有一层难还原的氧化物膜,影响了质量。本文介绍用氧化物生成自由能比铬、铝、钛、硅、硼更低的氢化钙作还原剂制高合金钢与合金粉的工艺和计算混合料的方法。文中还以Cr18Ni15、Cr28、OCr18Ni9、1Cr18Ni9Ti、1Cr17Ni2、Cr20Ni80和司太利合金为例介绍用氢化钙共还原制造粉末的工艺过程,计算混合粉料的组成,和用这些金属粉末做成的材料的化学成分与机械性能。     

Ni80Cr20合金薄膜制备影响因素的试验研究

利用直流磁控溅射的方法制备Ni80Cr20合金薄膜,以氩气流量、氩气工作压强、溅射功率作为三因素进行正交试验,在溅射时间相同的条件下分别测试了薄膜厚度、表面粗糙度、电阻率并进行了极差分析。分析结果表明:在一定范围内,氩气工作压强与溅射功率对薄膜厚度的影响较大;在氩气工作压强为3.0Pa时,薄膜厚度与溅射功率近似成正比关系;随着氩气流量的增大,Ni80Cr20薄膜厚度呈现先增大后减小的趋势;在氩气流量为50cm~3/min时,薄膜厚度达到最大值;各因素对薄膜表面粗糙度及电阻率影响不明显。     

溅射法制备多层膜沉积速率的标定

为消除溅射沉积多层膜过程中产生的膜厚随机误差,实现多层膜膜厚的精确控制,提出了一种精确标定薄膜沉积速率的方法。该方法通过对多次实验结果进行最小二乘拟合得到薄膜沉积速率。对随机误差基本特性的分析表明,随着实验次数的增加,沉积速率将逐渐逼近真值。基于这一原理,可以对薄膜的沉积速率进行精确标定,同时提取出膜厚随机误差,进而确定镀膜机的膜厚控制精度,获得精确控制多层膜膜厚所需要的完整信息。选用两种精度不同的沉积设备,采用提出的方法对所制备的多层膜进行了测试。结果表明,多层膜的膜厚控制精度随沉积设备而异:其中低成本的普通镀膜机只能实现0.1 nm的膜厚控制精度;而另一台性能较高的镀膜机的膜厚控制精度优于0.01 nm。     

镍铬钼合金在真空熔融CaCl_2-20%CaF_2盐中的腐蚀行为

采用浸没法腐蚀试验分别研究了00Cr16Ni75 Mo2Ti和Hastelloy N两种镍铬钼合金在800℃真空熔融CaCl2-20%CaF2(质量分数)盐中的腐蚀行为。结果表明:两种合金的腐蚀质量损失均随时间的延长而增大,腐蚀速率均随时间的延长而减缓,试验初期Hastelloy N合金的腐蚀速率明显大于00Cr16Ni75 Mo2Ti合金的;两种合金的腐蚀机理均主要为合金元素在熔盐中的选择性脱溶;析出相的不同是导致Hastelloy N合金腐蚀质量损失明显大于00Cr16Ni75 Mo2Ti合金的主要原因。     

Self-Lubricating Composites of Porous Nickel and Nickel-Chromium Alloy Impregnated with Barium Fluoride-Calcium Fluoride Eutectic

Porous nickel and nickel chromium were filled with BaF₂-CaF₂ eutectic composition by vacuum impregnation at 2000 F. The friction and wear properties of the resulting composites were determined in air and in hydrogen from 80 to 1500 F. Higher friction coefficients were obtained compared with coatings of the same fluoride composition on dense metals, however low wear and excellent wear life were obtained. The advantages of coatings (lower friction) and of composites (longer wear life) were combined by applying a thin sintered film (0.001-inch) of eutectic fluoride to the load-bearing surfaces of the composites. In a hydrogen atmosphere at a sliding velocity of 2000 ft per minute, typical friction coefficients for coated alloy composites were 0.06 at 1500 F, 0.18 at 500 F, and 0.20 at 80 F. Friction coefficients were higher at low sliding velocities. Composites with a nickel-chromium matrix were superior to nickel composites in load-carrying ability.     

Structure analysis of sputter-coated and ion-beam sputter-coated films: a comparative study

Gold, platinum and tungsten films were deposited by low energy input (7 mA, 450 V), or high deposition rate (80 mA, 1500 V), diode sputter coating and by ion beam sputter coating. Film structures on Formvar coated grids and on the surface of coated erythrocytes, resin embedded, sectioned, and recorded at high magnification in a TEM were compared using computer-assisted measurements and analysis of film thickness and grain size. The average grain size of the thinnest gold and platinum films was relatively independent of the mode or rate of deposition but as the film thickness increased, significant differences in grain size and film structure were observed. Thick platinum or gold films deposited by low energy input sputter coating contained large grain size and electron transparent cracks; however, more even films with narrower cracks but larger grain size were produced at high deposition rates. Ion beam sputter coated gold had relatively large grain size in 10 nm thick films, but beyond this thickness the grains coalesced to form a continuous film. Platinum films deposited by ion beam sputter coating were even and free of electron transparent cracks and had a very small grain size (1–2 nm), which was relatively independent of the film thickness. Tungsten deposition either by low energy input or ion beam sputter coating resulted in fine grained even films which were free of electron transparent cracks. Such films remained granular in substructure and had a grain size of about 1 nm which was relatively independent of film thickness. Tungsten films produced at high deposition rates were of poorer quality. We conclude that thick diode sputter coated platinum and gold films are best deposited at high deposition rates provided the specimens are not heat sensitive, the improvement in film structure being more significant than the slight increase in grain size. Thick diode or ion beam sputter coated gold films should be suitable for low resolution SEM, and thin discontinuous gold films for medium resolution SEM. Diode sputter coated platinum should be suitable for medium resolution SEM and ion beam sputter coated platinum for medium and some high resolution SEM. 1–5 nm thick tungsten films, deposited by low energy input or ion beam sputter coating should be suitable for high resolution SEM, particularly where contrast is of less importance than resolution.     

Vacuum ellipsometry as a method for probing glass transition in thin polymer films

A vacuum ellipsometer has been designed for probing the glass transition in thin supported polymer films. The device is based on the optics of a commercial spectroscopic phase-modulated ellipsometer. A custom-made vacuum chamber evacuated by oil-free pumps, variable temperature optical table, and computer-based data acquisition system was described. The performance of the tool has been demonstrated using 20-200 nm thick poly(methyl methacrylate) and polystyrene films coated on silicon substrates at 10(-6)-10(-8) torr residual gas pressure. Both polymers show pronounced glass transitions. The difficulties in assigning in the glass transition temperature are discussed with respect to the experimental challenges of the measurements in thin polymer films. It is found that the experimental curves can be significantly affected by a residual gas. This effect manifests itself at lower temperatures as a decreased or even negative apparent thermal coefficient of expansion, and is related to the uptake and desorption of water by the samples during temperature scans. It is also found that an ionization gauge--the standard accessory of any high vacuum system--can cause a number of spurious phenomena including drift in the experimental data, roughening of the polymer surface, and film dewetting.     

沉积温度对脉冲真空弧源沉积类金刚石薄膜性能的影响

利用脉冲真空弧源沉积技术在Cr17Ni14Cu4不锈钢和Si(100)基体上制备了类金刚石(DLC)薄膜,研究了基体沉积温度对DLC薄膜的性能和结构的影响。研究表明,随着沉积温度由100 ℃提高到400 ℃,DLC薄膜中sp3 键质量分数减少,sp2键质量分数增多,薄膜复合硬度逐渐降低。当DLC薄膜沉积温度达到400 ℃时,薄膜中C原子主要以sp2键形式存在,与沉积温度为100 ℃时制备的DLC薄膜相比,薄膜复合硬度降低50%。DLC薄膜具有优异的耐磨性,摩擦因数低,随着沉积温度由100 ℃提高到400 ℃,Cr17Ni14Cu4不锈钢表面沉积的DLC薄膜耐磨性降低。沉积温度为100 ℃时,Cr17Ni14Cu4不锈钢表面沉积的DLC薄膜后,耐磨性大幅度提高。DLC薄膜与不锈钢基体结合牢固。     

Au/Cr Sputter Coating for the Protection of Alumina During Sliding at High Temperatures

A sputter-deposited bilayer coating of gold and chromium was investigated as a potential solid lubricant to protect alumina substrates in applications involving sliding at high temperatures. The lubricant was tested in a pin-on-disk tribometer with coated alumina disks sliding against uncoated alumina pins. Three test parameters—temperature, load and sliding velocity—were varied over a wide range in order to determine the performance envelope of the Au/Cr solid lubricant film. The tribo-tests were run in air at temperatures of 25° to 1000°C, under loads of 4.9 to 49.0 N and at sliding velocities from 1 to 15 ms^?1. Posttest analyses included surface profilometry, wear factor determination and SEM/EDS examination of worn surfaces.

Compared to unlubricaled Al₂O₃ sliding, the use of the Au/Cr film reduced friction by 30 to 50 percent and wear by one to two orders of magnitude. Increases in test temperature resulted in lower friction and the Au/Cr film continued to provide low friction, about 0.3, even at 1000°C. Pin wear factors and friction were largely unaffected by increasing loads up to 29.4 N. Sliding velocity had essentially no effect on friction, however, increased velocity reduced coaling life (total sliding distance). Based upon these research results, the Au/Cr film is a promising lubricant for moderately loaded, low-speed applications operating at temperatures as high as 1000°C.     

Al、Sn掺杂对于ZnO薄膜微结构及光学特性的影响

采用真空电子束蒸发金属薄膜及后续热氧化技术在石英衬底上分别制备出了ZnO、Al∶ZnO以及Sn∶ZnO薄膜。通过X射线衍射仪(XRD),紫外-可见分光光度计和原子力显微镜(AFM)等分析仪器对比研究了Al、Sn掺杂对ZnO薄膜结晶质量、光学性质及表面形貌的影响。测试结果表明,Al、Sn掺杂可以使薄膜结晶质量得到提高,薄膜应力部分释放,薄膜表面的粗糙度也相应增加,掺杂对薄膜光学带隙的影响在一定程度取决于金属薄膜的氧化程度,氧化充分可以使光学带隙变宽,反之则变窄。     

Microstructures and abrasive wear performance of PTAW deposited Ni–WC overlays using different Ni-alloy chemistries

The microstructures and performance of Ni–WC (nickel–tungsten carbide) composite overlays deposited by plasma transferred arc welding are studied using a combination of microscopy, hardness, and wear testing. The Ni–WC overlays had microstructures consisting of γ-Ni dendrites, with interdendritic Ni-based eutectics, borides and carbides. Overlays which were produced with a low hardness Ni-alloy matrix contained a smaller fraction of interdendritic phases relative to the high hardness Ni-alloys.The dissolution of WC particles was observed following deposition of the MMCs, and this promoted the formation of secondary carbide phases. Ni-alloys with low carbon and low Cr content exhibited the least dissolution of WC. The Ni–WC overlays produced using these dilute alloys generally performed better in ASTM G65 wear tests. This was due to the increased fraction of retained WC phase, and the reduced fraction of brittle secondary carbide phases when the Ni-alloy contained no Cr.