Sn-Al合金基镀Ni光纤光栅传感器研究

制备了熔点约为350℃的Sn-Al合金,利用真空熔铸法将化学镀Ni后的光纤布拉格光栅(FBG)传感器铸造到Sn-Al合金中,以改善FBG传感器与金属结构的焊接性能,达到对金属结构材料的传感增敏作用。传感器的温度标定实验结果表明:镀Ni的FBG传感器经过熔点350℃的Sn-Al合金熔铸封装后FBG传输信号正常,并且其温度传感灵敏系数从裸FBG传感器的10.8pm/℃增加到升温阶段的17.3pm/℃和降温阶段的17.4pm/℃。     

镀Ni光纤布拉格光栅温度灵敏度分析

为了研究镀Ni光纤布拉格光栅(FBG)的温度灵敏度,根据镀Ni FBG的特点,分析了镀Ni FBG温度变化时的应力应变,从理论上推导出镀Ni FBG的温度灵敏度公式并通过实验进行了验证,用理论证明了镀Ni FBG的波长漂移、应力和应变与温度变化成线性关系,分析了镀Ni FBG的温度灵敏度与镀层厚度的关系.用ANSYS软件对镀Ni FBG在温度变化时的应力应变进行了仿真.理论分析得到镀层厚度为4.56 μm的镀Ni FBG的温度灵敏度为14.3306 pm/℃,实验值为14.113 pm/℃.理论、实验和仿真得到了一致的结果.     

纳米化学复合镀的开发及在PCB制造中的应用研究

化学镀表面处理技术使用范围很广,镀层均匀、装饰性好;在防护性能方面,能提高产品的耐蚀性和使用寿命;在功能性方面,能提高加工件的耐磨性和导电性、润滑性能等特殊功能,因而成为表面处理技术的一个重要部分。钠米化学复合镀是在化学镀液中加入纳米粒子,使其与化学镀层共沉积的工艺技术。文章主要研究在化学镀Ni-P中加入纳米颗粒,在基体表面沉积具有镀厚均匀、耐磨、耐腐蚀、可焊的纳米复合镀层,阐明镀液组成和工艺条件对沉积速率、镀液稳定性、镀层与基体的结合力的影响,获得钠米化学复合镀技术的工艺参数,并对纳米复合镀层的性能进行了研究。     

化学镀Ni-P镀层状态对引线键合的影响(2)

(接上期)3.3化学镀Ni-P析出状态时对Ni局部腐蚀的影响析出状态为层状和柱状析出的化学镀Ni-P镀层之间确认了镀Au层表面上扩散的Ni浓度的差异。这是由于与还原镀Au置换镀Au时进行的Ni局部腐蚀现象有关,观察了还原镀Au层/置换镀Au层/Ni-P镀层的截面和剥离镀Au层以后的Ni镀层状态。如     

镀Cu光纤Bragg光栅高温实验研究

将普通的光纤Bragg光栅(FBG)表面均匀地进行化学镀Cu,然后设计合理的测温装置对处理后的FBG进行高温实验.实验证明,经过表面镀Cu的FBG能够测量300 ℃的高温,线性度、准确度均较高,重复性也较好,而且可以通过控制镀层的厚度来控制其热膨胀系数,进而可以得到特定温度灵敏度的镀Cu FBG温度灵敏度可提高2.4倍.进一步的实验验证了使用该FBG进行450 ℃的高温测量也是可行的.     

激光熔凝NiAl/纳米Al2O3化学复合镀层抗高温氧化性能

采用大功率连续横流CO2激光对化学复合镀NiAl/纳米Al2O3复合镀层进行激光熔凝处理,并对熔凝层的抗高温氧化性能进行研究。采用X射线衍射仪(XRD)、扫描电镜(SEM)和能谱仪(EDS)等分别对高温氧化前后的表面形貌、物相组织和元素组成进行表征分析。与复合镀层和基体试样相比,激光熔凝后表面抗高温氧化性能明显提高,这一方面与激光熔凝镀层中的金属间化合物NiAl2O4、Ni0.77AlFe0.23在800℃时具有良好的抗高温氧化性有关,另一方面是由于激光熔凝后镀层表面形成了连续致密的氧化膜。     

磁性材料、超导材料和器件

T入1271 01020060热处理对化学镀钻硼合金结构和磁学性能的影响/郑晓华,马晓春,宣天鹏,邓宗钢(浙江工业大学)办浙江工业大学学报.一2000,28(2).一104一107利用Dlll:1x/rb旋转阳极X射线衍射仪分析了化学镀C。-B合金镀层的晶化过程,并采用L DJ一9000振动试样型磁强计i9ll]定了镀层磁学参数.结果表明,镀层(B质量分数为5 .1%)在镀态时具有非晶态结构,经400℃ Zh热处卿昆镀层由非晶态向。一c。转变,并出现口一c。和COZB相:600℃lh热处理后,镀层由p一Co和CoZB相组成.镀层经热处理后,其矫顽力H。二大幅度上升(最大2 11‘goe),H。//基本不变…     

化学镀镍/化学镀钯/浸金表面涂覆层的再提出

文章概述了化学镀镍/化学镀钯/浸金表面涂(镀)覆层的特性.不仅它能够满足各种各样的类型元件和安装工艺的要求,而且也能满足高密度的IC基板封装的要求.因而,化学镀镍/化学镀钯/浸金表面镀层是一种"万能"的镀层,具有最广泛的应用前景.     

镀Ni硅酸钙镁晶须对屏蔽涂料电磁性能的影响

为了改善硅酸钙镁晶须的电磁性能,先用化学镀技术制备镀Ni硅酸钙镁晶须,将其与镍粉复合,制备了一种新型电磁波屏蔽涂料,并研究其电磁性能.结果表明:镀Ni硅酸钙镁晶须中Ni的质量分数为7.28%;其结构和形貌与镀前相比没有明显改变;屏蔽涂料中镀Ni硅酸钙镁晶须的最佳质量分数为4%,当涂层厚度为0.3 mm时,涂层的电阻率由2.40 Ω·cm降至1.43 Ω·cm;在0.3～1 000.0 MHz时,涂层的电磁屏蔽效能提高至35.082～41.924 dB.     

化学镀Ni-P镀层状态对引线键合的影响（1）

观测了化学镀Ni/Au工艺中化学镀Ni-P镀层的状态,评估了基底化学镀Ni-P镀层的P含量和Ni析出状态对引线键合性的影响。     

光纤光栅无应力毛细铜管封装及温度特性实验

为克服裸光纤布拉格光栅(FBG)脆弱易折断的缺点,提出了一种聚合物和毛细铜管相结合的封装工艺。先用丙烯酸酯对栅区进行二次涂覆,再将二次涂覆后的FBG封装在毛细铜管内,FBG在毛细铜管内处于有余长无应力状态,二次涂覆为裸FBG提供了有效的保护。测试结果表明,二次涂覆并没有改变FBG的温度灵敏度;较薄的涂覆厚度保证了涂覆的均匀性和涂覆后光谱的质量;无胶空管封装方式消除了聚合物内部应力对温度测量精度的影响。封装后的温度特性实验表明,FBG传感器线性度为0.999 29,温度灵敏度为13.675pm/℃,重复性较好。     

Dual functional performance of fiber Bragg gratings coated with metals using flash evaporation technique

Metallic and other type of coatings on fiber Bragg grating (FBG) sensors alter their sensitivity with thermal and mechanical stress while protecting the fragile optical fiber in harsh sensing surroundings. The behavior of the coated materials is unique in their response to thermal and mechanical stress depending on the thickness and the mode of coating. The thermal stress during the coating affects the temperature sensitivity of FBG sensors. We have explored the thermal response of FBGs coated with Al and Pb to an average thickness of 80 nm using flash evaporation technique where the FBG sensor is mounted in a region at room temperature in an evacuated chamber having a pressure of 10^?6 Torr which will minimize any thermal stress during the coating process. The coating thickness is chosen in the nanometer region with the aim to study thermal behavior of nanocoatings and their effect on FBG sensitivity. The sensitivity of FBGs is evaluated from the wavelengths recorded using an optical sensing interrogator sm 130 (Micron Optics) from room temperature to 300 °C both during heating and cooling. It is observed that the sensitivity of the metal coated fibers is better than the reference FBG with no coating for the entire range of temperature. For a coating thickness of 80 nm, Al coated FBG is more sensitive than the one coated with Pb up to 170 °C and it reverses at higher temperatures. This point is identified as a reversible phase transition in Pb monolayers as the 2-dimensional aspects of the metal layers are dominant in the nanocoatings of Pb. On cooling, the phase transition reverses and the FBGs return to the original state and for repeated cycles of heating and cooling the same pattern is observed. Thus the FBG functions as a sensor of the phase transitions of the coatings also.     

光纤布拉格光栅温度传感增敏特性的实验研究

分别以铜、铝、有机玻璃、聚四氟乙烯为实验衬底材料,对采用片式粘敷封装技术的光纤布拉格光栅温度传感增敏特性进行了实验研究。研究结果表明,当对两侧尾纤有涂覆层的光纤布拉格光栅进行封装时,其温度灵敏系数分别是裸纤情况下的2.3倍、2.9倍、5.2倍、11.7倍。然而,粘敷材料在较高温度时显著的热膨胀会引起光纤包层与涂覆层发生一定的脱离,导致此时其实验结果重复性不甚理想。为了克服这种不利情况,对尾纤无涂覆层的光纤布拉格光栅进行了封装测试。在测试温度范围内,其反射波长随温度的变化始终呈现良好的线性关系,其温度灵敏系数分别提高到了3倍、3.4倍、9.2倍、12.6倍,测量结果重复性良好。研究结果为将来片式封装光纤布拉格光栅传感器的温度增敏特性的研究,提供了必要有益的数据支持和参考。     

Effect of fiber coating on temperature sensitivity in polarimetricsensors

The effect of fiber coating on the temperature sensitivity in a polarimetric sensor has been investigated using the concept of finger prints for bare birefringent fibers. An accurate, simple mechanical model has been proposed for the analysis of phase sensitivity through stress analysis for multiply coated birefringent fibers. It is found that a singly coated fiber has a higher temperature sensitivity than a doubly coated fiber with a silicone buffer coating. Both singly and doubly coated birefringent fibers can have their temperature sensitivities nullified by choices of fiber coating     

基于PI湿敏薄膜的分布式光纤Bragg光栅湿度传感器

研究了基于聚酰亚胺（PI）湿敏薄膜的分布式光纤Bragg光栅（FBG）湿度传感器。传感器利用PI薄膜湿膨胀效应,将湿应变作用于Bragg栅区,从而改变光纤FBG湿度传感器中心波长的原理,实现了对26-98％RH范围内环境相对湿度的监测。通过改进PI湿敏薄膜的制备及涂覆工艺,有效提高了FBG湿度传感器性能,并采取了相应温...     

FBG湿度传感特性的研究

在研究光纤布拉格光栅（FBG）传感器的基础上,分析了FBG的湿度传感特性。以聚酰亚胺（PI）薄膜为湿敏涂覆层的FBG,当湿度升高时,由于涂覆层的膨胀,导致FBG因应变而增长,使布拉格波长发生变化,从而实现对湿度传感。实验结果表明,PI薄膜涂覆的FBG是一种性能很好的湿度传感元件。     

Optical hydrogen sensor based on etched fiber Bragg grating sputtered with Pd/Ag composite film

A novel fiber optical fiber hydrogen sensor based on etched fiber Bragg grating coated with Pd/Ag composite film is proposed in this paper. Pd/Ag composite films were deposited on the side-face of etched fiber Bragg grating (FBG) as sensing elements by magnetron sputtering process. The atomic ratio of the two metals in Pd/Ag composite film is controlled at Pd:Ag = 76:24. Compared to standard FBG coated with same hydrogen sensitive film, etched FBG can significantly increase the sensor’s sensitivity. When hydrogen concentrations are 4% in volume percentage, the wavelength shifts of FBG-125 μm, FBG-38 μm and FBG-20.6 μm are 8, 23 and 40 pm respectively. The experimental results show the sensor’s hydrogen response is reversible, and the hydrogen sensor has great potential in hydrogen’s measurement.     

Active Fiber Bragg Grating Hydrogen Sensors for All-Temperature Operation

The use of liquid hydrogen as a fuel requires low-cost multipoint sensing of hydrogen gas for leak detection and location well below the 4% explosion limit of hydrogen. Herein is presented a multipoint in-fiber hydrogen sensor capable of hydrogen detection below 0.5% concentration with a response time of less than 10 s. Our solution entails use of a fiber Bragg grating (FBG) coated with a layer of hydrogen-absorbing palladium which, in turn, induces strain in the FBG in the presence of hydrogen. Infrared power laser light is used to induce heating in the palladium coating which dramatically decreases sensor response time and increases the sensor's sensitivity at low temperatures. This technology promises an inexpensive fiber solution for a multipoint hydrogen detection array with only one fiber feed-through     

基于双光栅级联结构的温度及浓度传感特性测试

研究了长周期光纤光栅（LPFG）级联布拉格光纤光栅（FBG）结构的温度及浓度传感特性。利用飞秒激光直写制作LPFG并级联FBG,且FBG波谷位于1 551.9 nm,LPFG波谷位置为1 560.5 nm。在30~50℃温度变化范围内对传感器温度特性进行测试,并在25℃超净环境下对浓度为3%~30%的葡萄糖溶液进行敏感性测试。实验结果表明:升温过程FBG中心波长发生红移,灵敏度26.36 pm/℃,线性度0.950 8;LPFG中心波长发生蓝移,灵敏度-24.55 pm/℃,线性度0.914 2。降温过程FBG中心波长发生蓝移,灵敏度25.00 pm/℃,线性度0.945 8;LPFG中心波长发生红移,灵敏度为-21.82 pm/℃,线性度0.921 2。FBG对浓度变化不敏感,当浓度由3%增至30%时,LPFG中心波长发生蓝移,灵敏度196.36 pm,线性度0.956 5。结果表明该光纤传感器灵敏度高,线性度好,可以同时动态实现温度和浓度的测量。