Fe-Ni-P合金改性空心微珠及吸波性能研究

采用化学镀的方法制备了表面包覆Fe-Ni-P合金的空心微珠,研究了制备方法及条件对空心玻璃微珠表面改性的影响,并对其吸波性能进行了测试.实验结果表明,空心玻璃微珠表面镀层中铁、镍的质量分数分别为30.1%和63.2%,在频率为16.80 GHz处,涂层的反射衰减可达-18.20 dB,且在12.5 ～18.00 GHz频段范围内,反射衰减皆低于-10.00 dB.     

关于红外加热技术及其应用的讨论(六) 红外涂料增加辐射作用的验证

红外涂料究竟能否增加辐射作用,在这个问题上有两种截然不同的学术观点:肯定者认为,加热器由于涂复了红外涂料而增大了比辐射率,从而也就增加了红外辐射能。否定者认为,当比辐射率增大时,加热器表面的温度却降低了,因此辐射能并未得到增加,由此得出结论:有没有涂料都一样。针对上述观点,笔者进行了能量守恒计算和实验测量,结果表明,前者的观点是正确的,即在加热功率不变的条件下,由于比辐射率增大,虽然表面温度降低,但红外辐射能仍然增加,这就是说,红外涂料是能够增加辐射作用的。     

填料表面改性技术在红外隐身涂料中的应用

填料是决定红外隐身涂料红外性能的关键因素。从红外隐身原理出发,得出降低目标红外辐射强度的2个措施:降低红外发射率和控制表面温度。综述了包覆改性、微胶囊改性、化学镀表面改性和表面化学改性等4种填料表面改性技术及其在红外隐身涂料中的应用进展情况。最后,展望了填料表面改性技术在红外隐身涂料中应用的发展方向。     

热网管道金属围护表面比辐射率的测量研究

本文分析了热网管道围护表面比辐射率的大小对传热状态及热损失的影响,并作了实验观测。根据红外测温的特点,提出了用“等效温度法”测量金属围护表面比辐射率的方法。     

红外与毫米波学报 第十卷年度索引(一九九一年)

主题索引半磁半导体 —Cdlwe袋m二T。光学和磁学性质的研究 (27)。 —HgCdT气HgMnTe的自由载流子吸收 (公以). —CdPe叽能隙的温度和压力效应(Z住). 一CdT舜sm晶体的红外光谱(韶3). —Hgse:Fe的红外光谱和自由载流子散射 (341).耽辐射率(有效比辐射率) —双重柱形腔低温面源黑体有效比辐射率的 计算,风云一号气象卫星红外定标(203). —采用双园筒法,用高灵敏红外测温仪测量 (段巧).玻璃 —稀土元素在氟铝酸盐玻璃中吸收损耗 (175). —氟化物玻璃(2~5仲m)红外光纤的发展 (盛15).毖膜 —GaA。表面热壁外延生长Z胡白单晶薄膜 (57)。 一…     

热像仪测量物体表面辐射率及误差分析

根据红外辐射理论，通过分析红外成像仪辐射测量的基本原理，得到了计算被测表面辐射率的计算公式；讨论了影响热像仪测量误差的各种因素，给出了估计表面辐射率误差的计算公式。最后，介绍了几种测量辐射率的有效方法。     

红外技术应用及其进展

红外技术应用日益广泛,新的应用提出了一些新的问题和要求,促进了红外技术的进一步发展。本文从以下几个方面加以介绍。一、红外测温红外测温的特点是非接触、快速和灵敏,但准确度不高。原因是红外测温是通过测量红外辐射推算物体的温度。红外辐射不仅是温度的函数,还是物体表面比辐射率ε的函数,另外还受环境辐射的影响。因此红外测温在高的背景辐射和小的比辐射率的物体为对象应用时特别困难。而现在往往对此很感兴趣。例如:     

纤维基低发射率隔热材料制备研究

兼具表面低红外发射率和隔热性能的功能纺织材料在工业及军事领域有着广泛用途。从利用低表面发射率和控制物体表面温度两方面,研究制备具有低红外发射率且隔热性能良好的功能材料。选用聚丙烯酸酯(PA)作为成膜粘结物质,研究了铝粉的粒径及用量对涂层红外发射率的影响;以不同的空心微珠为隔热填充剂,并对其用于涂层织物的隔热效果进行探究。最后,将低发射率涂层与隔热涂层进行复合,制备出兼具低发射率与隔热性能的材料。结果表明,采用400目片状铝粉时的发射率比采用600目时更低,20%的400目片状铝粉的涂层胶所制备的涂层表面的红外发射率低至0.237。由于空心微珠是较好的隔热填料,以共混15%的玻璃微珠为隔热层,以共混20%的400目片状铝粉为低红外发射率涂层,所制备的纤维基复合涂层材料的发射率为0.507,热体试样与背景温差为3.75℃,具有较好的隔热性能和低红外发射率。     

新型热红外伪装涂料用填料中空微珠性能研究

分析了温度对涂层发射率的影响，并据此重点研究了一种新型热红外伪装涂料用填料——中空微珠——的常规使用性能、降温效果以及对涂层发射率的影响。研究认为，中空微殊用量小于20％、粒径为200目左右时常规使用性能最好。60目的中空微殊降温效果最好，而且当其用量小于20％时，中空微珠对涂层的发射率基本没有影响。     

石墨涂层材料红外辐射率研究

以改性氟碳树脂为黏合剂,石墨粉为填料,制出了在红外波段具有较低辐射率的红外隐身涂料.研究结果表明,在黏合剂中加入质量分数为25%的石墨,且石墨粒径为2μm时,所制得的红外隐身涂料辐射率最低可达0.63.该涂层的附着力为一级,耐冲击性大于等于50kg·cm,耐酸碱性和耐盐水性能良好.     

Factors Affecting the Morphology of Pb-Based Glass Frit Coated with Ag Material Prepared by Electroless Silver Plating

Pb-based glass frit coated with nanosilver material for Si solar cell applications has been directly prepared by electroless silver plating. Activation of the glass frit was accomplished by using glycol, with the aim of reducing the silver ions to elemental silver on the surface of the glass frit. Electroless silver plating onto the glass frit was successfully realized using two kinds of electroless plating bath. However, the morphology of the composite powder greatly affected the modality, sheet resistance, series resistance, and photoelectric conversion efficiency of the conducting silver films. We found that the activation temperature affected the number and distribution of silver nanoparticles. Meanwhile, the average grain size of the silver particles and the silver content in the Pb-based glass frit coated with Ag material could be controlled by adjusting the pH value and loading capacity, respectively, during plating.     

酸洗前处理对叠层片式电感器焊接性的影响

采用电子扫描电镜和能谱分析研究了叠层片式电感器(MLCI)端电极的三层结构对焊接性的影响。利用氢氟酸(HF)具有强氧化性的特点对产品端电极银层进行微蚀前处理以起到整平作用,利于镀层的生长。试验结果证明前处理酸洗工艺能够有效改善产品镀层的焊接性。使用质量分数2%的HF进行酸洗,能够有效去除端电极银镀层上的玻璃相成分(SiO2),从而使电感器镀层表面上锡覆盖率大于90%。     

The effects of electroplating parameters on the composition and morphology of Sn-Ag solder

The Sn-Ag solder was electrodeposited from a bath that basically is composed of tin sulfate (SnSO₄), silver nitrate (AgNO₃), and thiourea (CH₄N₂S), acting as a complexing agent to silver. The composition and morphology of electrodeposited Sn-Ag solder were studied in terms of silver concentration in bath current density, duty cycle, and additives. It was possible to control silver content in the electrodeposit by means of varying silver concentration in bath and current density. The microstructure and surface morphology of the electrodeposit become finer and smoother with increasing current density. The pulse-current (PC) plating method was applied to compare to the conventional direct-current (DC) plating. Varying duty cycle in PC plating did not change the microstructure in general, but some improvement in surface roughness was observed compared to DC plating. However, the silver composition in the electrodeposit increased with decreasing the duty cycle at a constant current density. An addition of a surface-active agent helped to reduce the surface roughness and the variation of silver content in the electrodeposit. In an optimum condition, eutectic Sn-Ag solder bumps with a fine pitch of 30 μm and height of 15 μm were successfully electroplated. The composition of Sn-Ag bumps was analyzed by energy dispersive x-ray spectrometry (EDS) and wavelength dispersive x-ray spectrometry (WDS) methods, and the surface morphology was characterized by scanning electron microscopy (SEM) and a three-dimensional surface analyzer.     

Hygrothermal Stability of Electrical Contacts Made from Silver and Graphite Electrically Conductive Pastes

The hygrothermal stability of electrical contacts made from silver and graphite electrically conductive pastes is comparatively evaluated by measurement of the increase in contact electrical resistance during immersion in water at 15°C and 40°C. The pastes are silver paint, silver paint with a nonconductive epoxy overcoat, silver epoxy, and graphite colloid. Each electrical contact is made between a seven-strand tin-coated copper wire and the surface of a carbon fiber epoxy-matrix composite. Silver paint and graphite colloid penetrate the spaces among the 130-μm-diameter strands, but silver epoxy does not. Partly due to its low penetrability and the silver flake (15 μm) preferred orientation, silver epoxy gives contacts of significantly higher resistance than silver paint. Graphite colloid is comparable to silver epoxy in the resistance. Among the four pastes, silver paint with an epoxy overcoat is most durable, though it gives slightly higher resistance than silver paint without epoxy. Silver epoxy is less durable than silver paint without an epoxy overcoat, particularly at 40°C, due to the low hygrothermal stability of epoxy. Graphite colloid is even less durable than silver epoxy, due to its being water based.     

Applied whispering gallery modes on ZnO nanorods coated glass for humidity sensing application

In this letter, a humidity sensor is demonstrated by applying a whispering gallery mode (WGM) from a microsphere resonator onto the ZnO nanorods coated glass surface. The diameter of the microsphere was 234 µm and the glass surface was coated with ZnO nanorods using the hydrothermal method at growth duration of 12 h. A significant response to humidity level ranging from 35%RH to 85%RH has been observed with the sensitivity of 0.014 2 nm/%RH. The proposed humidity sensor has successfully employed to enhance interaction between the whispering gallery mode evanescent and surrounds analyte with the assistance of ZnO nanorods coated glass.     

Polymer coating on infrared silver halide fiber for photodarkeningprotection

Infrared silver halide fibers were studied concerning the optical degradation induced by photodarkening. Infrared transmittance decreased notably in the shorter wavelength (near-infrared) region by the exposure to ultraviolet (UV) or visible light below a wavelength of ~600 nm. Black paint was tentatively coated on the unclad fiber for photodarkening protection, but the infrared transmittance of the fiber decreased heavily due to the evanescent wave absorption by the paint. To reduce this absorption loss, a fluorocarbon polymer was coated between the fiber core and the black paint. Consequently, efficient transmission was realized in the infrared region except for the 7-10-μm wavelength range, where the fluorocarbon polymer has a strong absorption band. In the 2-7-μm wavelength range, the fiber that was heated at 100°C in the polymer coating process exhibited higher transmittance than the original uncoated fiber. No optical degradation of the coated fiber was observed, even after irradiation with UV light for a period of 70 h     

TiBa玻璃微球拉曼光谱的结构共振

分别测量了TiBa玻璃微球和TiBa平板玻璃的拉曼光谱,发现TiBa玻璃微球的拉曼光谱上有明显的结构共振,根据微球腔理论对其进行了分析,并利用Mie散射峰位计算公式对测量结果进行拟合,得到微球的直径为25．01μm,在拉曼位移300cm^-1(对632．8nm的激发光）附近的折射率为1．895。     

Thermal cycling induced wiping wear of connector contacts at150°C

Experiments were performed to study the contact resistance changes of several common connector contact materials (0.2% Co hard gold plate, Diffuse Gold Alloy (DGR-156), tin plated copper alloy and silver plated copper alloy) at 150°C. The emphasis was on contact degradation due to thermal expansion type of relative contact interface movement, i.e., low frequency (<0.01 Hz) and large wipe distance (>100 μm) fretting. The contact samples were the standard dimple-flat configuration. Electrical degradation in the form of contact resistance rise was measured. Scanning Electron Microscopy and Energy Dispersive Spectroscopy were used to analyze the surface morphology and composition changes. For the precious metal coating (hard Au plate, DGR-156 and Ag plate), wear through of the plating layer was found to be the cause of resistance increase. For the non-noble plating such as tin, contact resistance increased with oxide accumulation. Suitable lubricants were demonstrated to be effective for Sn plating to delay the resistance rise     

脉冲和连续模式下玻璃纤维复合材料激光脱漆技术研究(特邀)

采用波长为1 064 nm的纳秒激光器脉冲模式和连续模式分别对玻璃纤维增强树脂基复合材料表面涂覆的浅灰色防雨蚀涂层和抗静电涂层进行激光清洗实验,研究不同模式下激光参数对清洗效果的影响规律。通过SEM观察清洗后材料表面及清洗产物的微观形貌,运用EDS、FTIR分别检测清洗前后材料表面元素含量与化学官能团,采用COMSOL Multiphysics对清洗过程中的温度场进行分析。结果表明：去除单层抗静电涂层时,脉冲激光能完全去除该涂层且防雨蚀涂层损伤较小;去除双层涂层时,脉冲激光作用下试板表面有残余涂层,且易损伤下层清漆、树脂和纤维,而连续激光则可完全去除表面双层涂层,获得清洁的清漆表面。脉冲模式的去除机制主要为热弹性振动效应,连续模式下涂层的去除机制主要为热烧蚀效应。研究结果可为航空复合材料表面激光脱漆技术的激光模式选择提供参考。