Failure mode maps in the thin film scratch adhesion test

The scratch test has been used to assess thin coating adhesion for some time now. In this test a diamond indenter is drawn across the coated surface under an increasing load (either stepwise or continuous) until at some load, termed the critical load, L_c a well-defined failure event occurs; if this failure event represents coating detachment then the critical load can be used as a qualitative measure of coating-substrate adhesion. However, it is well known that a range of possible failure modes can occur and only some of these are dependent on adhesion. Other failure modes which depend on plastic deformation and fracture within the coating, rather than any adhesive failure at the coating substrate interface, may be just as useful in the assessment of coating quality particularly for tribological applications. In this paper the load regimes in which the main adhesion-related failure modes (spallation and buckling) occur as a function of coating thickness will be presented for thermally grown oxide and sputtered nitride coatings. The origin of the observed failure modes and the use of the scratch test to assess coating/substrate adhesion in a more quantitative fashion is discussed in the light of these observations.     

Effects of humidity on nano-oxidation of silicon nitride thin film

Effects of humidity on nanometer-scale oxidation of silicon nitride thin film using atomic force microscope in contact mode are studied at various values of relative humidity (RH) (30-70%). The shape of oxide protrusion is determined by the concentration of oxyanions under the tip apex and oxyanions diffusion laterally on the surface. At low RH (60%), the kinetics of silicon nitride oxidation has a logarithmic relationship to oxide height versus oxidation time. The threshold time decreased and initial oxidation rate increased simultaneously as humidity increased because a high concentration of oxyanions at the oxide/silicon nitride interface was generated. When a high sample voltage (9-10V) is applied at high RH (60%), the effective electric field is decreased because of the electron being trapped in the oxide and oxyanions accumulating on the oxide surface.     

Continuous planar phospholipid bilayer supported on porous silicon thin film reflector

Reconstituting artificial membranes for in vitro studies of cell barrier mechanisms and properties is of major interest in biology. Here, artificial membranes supported on porous silicon photonic crystal reflectors are prepared and investigated. The materials are of interest for label-free probing of supported membrane events such as protein binding, molecular recognition, and transport. The porous silicon substrates are prepared as multilayered films consisting of a periodically varying porosity, with pore dimensions of a few nanometers in size. Planar phospholipid bilayers are deposited on the topmost surface of the oxidized hydrophilic mesoporous silicon films. Atomic force microscopy provides evidence of continuous bilayer deposition at the surface, and optical measurements indicate that the lipids do not significantly infiltrate the porous region. The presence of the supported bilayer does not obstruct the optical spectrum from the porous silicon layer, suggesting that the composite structures can act as effective optical biosensors.     

新型多功能膜/基结合力测定仪的研制

采用改进划痕法原理及切向力检测临界载荷方法，研制了一种新型多功能膜／基结合力测定仪。该仪器结构新颖，实用简便，不仅能测定金属膜层与基体的结合强度，还能对金属膜层进行模拟单颗粒磨损试验。试验表明，该仪器具有较高的可靠性。     

Slow-neutron detector based on thin CVD diamond film

A slow-neutron detector based on thin CVD diamond film is discussed. A deep graphitized layer in the diamond film acts as one of the electrodes in the detector. The detector demonstrates low sensitivity to γ radiation, at the background level. The detector is tested with a laboratory neutron source based on the isotope ²⁵²Cf in a moderator. Slow neutrons are detected by means of the boron isotope ¹⁰В and lithium isotope ⁶Li. In both cases, slow neutrons are recorded with about 3% efficiency. The efficiency of slow-neutron recording is also assessed theoretically.     

利用方形四探针技术测量硅基片薄膜电阻的研究

提出硅基片生长薄膜的薄膜电阻的测试方法,利用方形四探针技术实现对较小硅基片上生长钴的薄膜电阻的测量,完成不同生长厚度下三片薄膜硅片的薄膜电阻测试工作,得出测试结果较可靠、合理的结论,同时对提高测试实验精度的影响因素进行分析。     

微型膜结构全光纤珐珀干涉高温传感器

制作了一种微型膜结构的全光纤在线珐珀干涉式高温传感器。该传感器是在单模光纤端面依次熔接一段大芯径空芯光纤和一段研磨的多模光纤膜片而构成的,因此,温度引起的珐珀腔光程差改变量由空芯光纤的热膨胀和温度引起腔内压强改变从而改变膜片的扰度两部分组成,从而使相同温度变化下传感器的光程差变化量更大,分辨率更高。实验结果表明,在100～650℃,该传感器单位温度变化的光程差变化量约为1.029 nm,温度分辨率约为1.5℃,测量线性度约为0.996 7,且滞回小,重复性好。这种膜结构的全光纤珐珀干涉式高温传感器因其体积小,温度分辨率高,将在多点高温测量领域有好的应用前景。     

米级弯月面化学薄膜涂覆装备的研制

弯月面化学涂膜技术因其具有大面积、低成本以及高效率等优势成为继旋涂、喷涂等传统涂膜工艺后极具发展潜力的新型化学薄膜涂覆技术。本文针对国家某重大项目对米级光学元件表面的化学薄膜涂覆需求,对基于弯月面涂胶的技术原理进行了系统研究,分析了涂胶压强、基片和狭缝间距以及材料亲疏水性与涂胶面形态的关系,实现了对弯月液面的精密调控并研制出基于弯月面化学薄膜涂覆技术的装备,在1 400mm×420mm尺寸玻璃基片上实现了光刻胶的均匀涂覆,使整体胶膜厚度误差4%,满足了米级元件表面精密化学薄膜的涂覆需求。     

Investigation of scratch resistance of thin carbon overcoat media using micro scratch testing

This paper investigates the scratch resistance of thin carbon overcoat media using a novel micro scratch testing method. Ramp loading was applied to a carbide blade, scratching along a rotating hard disk surface and the load corresponding to the penetration of the carbon overcoat, referred to as the critical load, was used as the measure of scratch resistance. The contact electric resistance (CER) at the cutting point of the blade/media interface was monitored through the scratch process and the critical load was determined when the CER dropped to zero. It has been found that CER monitoring is a very accurate and reliable way of determining the critical load. Scratches were characterized using scanning electronic microscopy (SEM) and it has been found that at the critical point the carbon overcoat was delaminated, peeled off, or plowed away. The micro scratch testing has shown to have the sensitivity to differentiate the effect of carbon thickness, carbon type, lubricant, and substrate type on media scratch resistance.     

基于Windows的硅机组测试系统的设计

介绍SS-3电力机车硅机组测试系统的设计方法和技巧，主要对系统的软硬件构成及面向对象的程序设计技术进行了探讨，叙述其相关的数据处理技术和数据库管理系统的开发技术。     

Low-cost embedded spirometer based on micro machined polycrystalline thin film

There is a great need for a low cost and low power consumption portable spirometer for the home care of respiratory diseases. A mobile monitoring system utilizing Bluetooth and mobile messaging services (SMS) with low-cost hardware equipment is proposed. A proof of concept prototype has been developed and implemented to enable transmission of a flow or volume of gas during inspiratory and expiratory process signal of a patient, which can be expanded to include other vital signs. Communication between a mobile smart-phone and the spirometer is implemented using the popular personal area network standard specification Bluetooth. We used SMS for transmission, the mobile phone plots the received signal and displays the flow measurement application software running on the client mobile phone itself, where the plot can be captured and saved as an image before transmission. The acquired signal is transmitted via the Bluetooth to the processing and diagnostic unit with wireless protocol between sensors and the electronics board. The flow measurement is done with a silicon hot wire anemometer manufactured with MEMS technology. The design, manufacturing, calibration, and basic characterization of MEMS hot-wire anemometer and digital spiromerter is presented.     

基于自适应进化算法的膜系自动设计

为获得性能更好、更易实现的膜系,提出一种基于自适应进化算法的膜系自动设计方法,并将该方法与常用设计方法进行比较。通过增益平坦滤光片、高反膜的实例优化表明,在相同设计要求下,用该进化算法可以得到更加合理的膜系结构,而且膜系结构简单,设计灵活,容易实现。理论和实践均表明该方法是高效和可靠的。     

Optimum film thickness of thin metallic coatings on silicon substrates for low load sliding applications

The frictional behaviour of thin metallic films on silicon substrates sliding against 52100 steel balls is presented. The motivation of this work is to identify an optimum film thickness that will result in low friction under relatively low loads for various metallic films. Dry sliding friction experiments on silicon substrates with soft metallic coatings (silver, copper, tin and zinc) of various thickness (1–2000 nm) were conducted using a reciprocating pin-on-flat type apparatus under a controlled environment. A thermal vapour deposition technique was used to produce pure and smooth coatings. The morphology of the films was examined using an atomic force microscope, a non-contact optical profilometer and a scanning electron microscope. Following the sliding tests, the sliding tracks were examined by various surface characterization techniques and tools. The results indicate that the frictional characteristics of silicon are improved by coating the surface with a thin metallic film, and furthermore, an optimum film thickness can be identified for silver, copper and zinc coatings. In most cases ploughing marks could be found on the film which suggests that plastic deformation of the film is the dominant mode by which frictional energy dissipation occurred. Based on this observation, the frictional behaviour of thin metallic coatings under low loads is discussed and friction coefficients are correlated with an energy based friction model.     

多层周期性薄膜结构的耦合波方法的研究

在分析耦合波方法与传输矩阵法相互联系的基础上以短波通薄膜滤光片为例,分别计算了正入射和斜入射情况下的修正耦合波方法的计算结果并与一般耦合波法、传输矩阵法计算的结果进行了比较,数值计算的结果表明在入射角度不是太大情况下,修正耦合波方法完全可以替代传输矩阵法对多层周期性薄膜结构进行分析和设计。     

Novel temperature dependent tensile test of freestanding copper thin film structures

The temperature dependent mechanical properties of the metallization of electronic power devices are studied in tensile tests on micron-sized freestanding copper beams at temperatures up to 400 °C. The experiments are performed in situ in a scanning electron microscope. This allows studying the micromechanical processes during the deformation and failure of the sample at different temperatures.     

基于SolidWorks的薄膜蒸发器三维参数化设计

随着三维CAD技术的发展,二维绘图已无法满足大部分客户的要求。在自行开发的薄膜蒸发器二维参数化设计系统的基础上,通过VisualBasic语言对SolidWorks软件进行二次开发,实现了薄膜蒸发器三维参数化设计及其虚拟装配设计。三维参数化技术的应用不仅提高了薄膜蒸发器的设计水平,缩短了开发周期,并为其进一步结构优化分析奠定基础。     

基于虚拟仪器的薄膜电阻率自动测量系统

薄膜样品相比半导体材料,电阻更小且材质脆弱,现有的四探针电阻率测量设备无法满足其测量要求.双电测组合法基于薄层原理,不需要尺寸修正,更适合应用于薄膜样品,且能适应小尺寸样品的测量.但是双电测组合法需要在测量过程中切换电路连接,且修正函数计算繁复.虚拟仪器技术将测量设备和计算机结合,编程完成测量过程和数据处理过程.本文介绍应用虚拟仪器技术实现双电测组合法自动化薄膜电阻率测量系统的过程,结合测量结果说明系统性能以及环境参数对测量结果的影响.     

基于改进型遗传算法的薄膜厚度及光学常数反演

准确的测量薄膜的厚度和光学常数,在薄膜的制备、研究和应用中都十分重要。借助Cauchy色散模型和P阶评函数,通过薄膜透过率测量曲线,用改进的遗传算法对透过率曲线进行全光谱拟合,从而反演得到薄膜的厚度和光学常数。理论验证是对电子束蒸发制备的TiO_2和反应磁控溅射制备的Si_3N_4薄膜进行测试拟合,计算得到的结果与文献报道的一致,误差小于0.5%。     

薄膜硅光伏组件的漏电通道模型及绝缘电阻的定量测试

为了研究薄膜硅光伏组件在高电压下的绝缘失效机制,建立了一个薄膜硅组件的漏电通道模型,并定量测试组件在湿热(damp heat,DH)实验前后各漏电通道的绝缘电阻,采用了独特的措施来避免各漏电通道之间的相互干扰,获得了较准确的结果.在DH实验之前,组件边缘的绝缘电阻比前后玻璃高20倍至2个数量级,前后玻璃处的漏电决定了组件绝缘性能.经过1 000h的DH实验之后,边缘绝缘电阻大幅下降约2个数量级,成为小面积(300 mm×300 mm)组件绝缘性能的决定性因素,但是在大面积(1300mm ×1 100 mm)组件中,前后玻璃在很多情况下仍是组件漏电流的主要通道.     

The study of the adhesion of a TiN coating on steel and titanium alloy substrates using a multi-mode scratch tester

A titanium nitride (TiN) coating was deposited by magnetron sputter ion plating onto steel and titanium alloy polished substrates. The adhesion of the coating on each substrate material was investigated using a newly developed multimode scratch tester. Progressive loading scratch tests, constant load scratch tests, multiple scratch tests in the same track and indentation tests were all performed. It was shown that the modified scratch tester can be used to identify not only coating detachment during progressive load scratch tests, but also other failure events such as cracking and cohesive damage to the coatings. By using the additional modes of operation, it was possible to study the fracture mechanisms in more detail i.e. chipping in the scratch track was cohesive for the TiN coated steel and adhesive for the TiN coated Ti alloy.