电镀工艺对铜锡合金镀层渗氢的影响

为了减少铜锡合金电镀过程中的渗氢,在调质处理钢上直流电镀和脉冲电镀铜锡合金,采用Devanathan装置原位测氢,研究了2种电镀工艺及工艺参数对电镀铜锡合金过程中渗氢行为的影响。结果表明:直流电镀时,随着电流密度的增加,稳态渗氢电流密度和渗氢量增加;脉冲电镀工件表面可扩散氢浓度较低,渗氢量较小;脉冲频率和占空比对脉冲电镀铜锡合金中稳态渗氢电流密度和渗氢量影响显著,当平均电镀电流密度为5 A/dm2时,脉冲频率为1 500 Hz,占空比为35%时,稳态渗氢电流密度最小,约为1.5μA/cm2,渗氢量最小,约为2.9 mL,较直流电镀降低了72%。     

脉冲电镀Zn-Ni合金工艺参数对镀层Ni含量及形貌的影响

为了优化Zn-Ni合金制备工艺,在硫酸盐型Zn-Ni合金镀液中脉冲电镀Zn-Ni合金层。分别采用扫描电镜和X射线成分分析镀层形貌和成分,通过中性盐雾试验测试镀层耐蚀性。研究了脉冲参数、工艺条件对Zn-Ni合金镀层Ni含量与形貌的影响。结果表明:镀液温度、平均电流密度、频率、逆向脉冲系数及占空比对镀层性能和形貌均有较大影响;最佳工艺参数为温度60℃,平均电流密度70 m A/cm2,脉冲频率200 Hz,逆向脉冲系数0.4,占空比0.7,此时Zn-Ni合金镀层晶粒细小,表面平整光亮,呈银白色,镀层Ni含量为13%,耐蚀性优良。     

水合肼还原铜氨废液制取纳米铜粉

以铜氨废液为原料,水合肼为还原剂制备纳米铜粉。在水合肼浓度为3mol/L、pH值为10.0、温度为75℃的条件下,铜离子沉淀率可达98.66%。采用X射线衍射仪对铜粉进行了表征,并讨论了制备条件对纳米铜粉的影响。     

电解法制备铜粉的影响因素的研究

电解法是制备铜粉的一种重要方法,铜粉的粒径和阴极的电流效率是其两个重要的指标。本文中从电解原理出发,从理论上阐述了电解液的酸度和温度、铜离子浓度、阴极电流密度等因素,对电解法制备铜粉的影响,并提出了电解过程中应注意的问题。     

高频脉冲电镀镍钴合金工艺及性能的研究

采用高频脉冲电流，制备Ni-Co复合镀层。通过正交试验设计的方法，重点考察了脉冲频率、占空比、平均电流密度、镀液pH值、温度及CoSO4·7H2O的浓度对镀层在15％H2SO4溶液中的阳极极化行为的影响，从而遴选出最佳电镀工艺：脉冲频率140kHz，占空比0．25，平均电流密度3A／dm，镀液pH值3，温度45℃，硫酸钴浓度20g／L。同时，对高频脉冲电镀与直流电镀进行比较。     

二次正交旋转组合法优化Ni-W-P脉冲电沉积工艺

为解决油田设备中油管与油杆的磨损与腐蚀问题,通过脉冲电沉积方法在抽油杆常用钢材30Cr Mo基体上制备了Ni-W-P三元合金镀层,采用5因素5水平的二次正交旋转回归组合试验,对温度、pH值、占空比、电流密度、频率等工艺参数进行了优选。采用显微硬度计对36组镀层进行显微硬度测试,利用DPS软件分析获得5因素与镀层硬度之间的数学模型,并研究了各参数的影响规律,获得了电沉积工艺参数最优组合。结果表明:pH值对镀层硬度影响效果最显著,温度、占空比和平均电流密度对镀层硬度的影响规律与pH值相似,均随变量的增大呈先增后减的趋势;在温度为60℃、pH值为8、占空比为0.8、平均电流密度为6 A/dm2、频率为80 Hz的优化工艺下获得的镀层硬度为812.4 HV2 N,自腐蚀电流密度为2.576μA/cm2,且镀层为非晶镀层,具有优良的耐磨、耐蚀性。     

电沉积法制备铜分散电极

研究了电沉积制备铜分散电极的方法,通过对阴极极化曲线的测试,考察了电流密度及不同冲击电流方式对铜粉粒度的影响。结果表明:适当的电流密度、合适的分散剂、间歇式的电流是得到较细铜粉的条件。同时对铜分散电极的电化学性质进行初步测试,结果表明铜粉细化以后,铜分散差电池的电动势值有所上升。     

高频脉冲电镀镍层内应力的研究

文章研究了不同脉冲参数如脉冲频率、占空比和电流密度等对高频脉冲电镀镍层内应力的影响,结果显示,随着脉冲频率的增大,镀镍层内应力先增大后减小,逐渐趋于平缓;随着占空比和电流密度的增大,内应力先减小后增大,在低电流密度区,应力值相当高,但在中等电流密度区应力有最小值。当在占空比为0．3,电流密度为7．5A／dm^2、频率为20kHz时,内应力最小。     

废退锡液中硝酸和锡的综合回收

通过考察铁盐、铜盐和亚锡盐对硝酸扩散系数的影响研究了采用扩散渗析法从废退锡液中回收硝酸的可行性,实际样品的研究表明,扩散渗析法回收硝酸的回收率在70％以上．余液利用离子膜-电沉积法回收其中的金属锡,最佳工艺条件为:温度30-40℃、槽电压3．5 V、电流密度1．0-2．3 A／dm2,并保持阳极液搅拌,此时锡的回收率达62％,电流效率在60％以上．结果表明,扩散渗析-离子膜-电沉积组合工艺可有效回收硝酸型废退锡液中的硝酸和锡,以实现其资源化利用．     

高频脉冲电镀制备Ni—Co／SiC复合镀层及性能研究

采用高频脉冲电源,在镍钴合金衬底上添加SiC,探索制备镍钴合金碳化硅镀层的最佳条件。较佳工艺条件为：频率80kHz,平均电流密度3A／dm^2,占空比0．24,温度为40摄氏度,添加剂为0．5g／L煮沸30min的十二烷基硫酸钠与1g／L糖精钠。通过SEM、XRD测试结果分析高频脉冲各条件对镀层性质的影响原因,研究了脉冲频率、占空比、电流密度、SiC及添加剂对镀层结构、耐腐蚀性的影响。相比相同条件下未添加SiC的镍钴合金镀层,高频脉冲镀层的孔隙率较低,表面致密均匀,耐腐蚀性较好,高频脉冲电镀Ni-Co／SiC合金镀层的耐腐蚀性随着频率的升高而显著增强。     

Duty cycle ratio dependence on the performance of a q-switched laser with an Er3+-Yb3+ codoped glass waveguide

We examine the performance of a hybrid Q-switched LiNbO(3) and Er(3+)-Yb(3+) doped glass waveguide laser as a modulation function of the duty cycle ratio. As the duty cycle ratio decreases, the laser operates at higher peak power and pulse width. At low duty cycle ratio (<1%), we observe variations in the Q-switched pulse shape; while the laser produces 59-W and 200-ns pulses to a 1-kHz repetition rate for a 50% duty cycle, it yields 27-W and 100-ns pulses to a 10-kHz repetition rate for a 0.01% duty cycle.     

Pulse Plating of Copper-ZrB2 Composite Coatings

Copper-zirconium diboride （ZrB2） composite coatings were fabricated using pulse plating technique to acquire a new type of EDM （electro-discharge machining） electrode material. The effects of pulse parameters, i.e., the average current density, the frequency and the duty cycle, on the incorporation of ZrB2 particles in the copper matrix were investigated. The amount＇of codeposited ZrB2 particles had a maximum at average current density of 3 A/din2 and increased with decreasing duty cycle as well as current frequency of the pulse current used for deposition. The hardness of the coatings increased with increasing ZrB2 percentage, whereas the incorporation of ZrB2 particles had little effect on the resistivity of the composites.     

Nickel pulse reversal plating for image reversal of ultrathin electron beam resist

The effects of various pulse reversal plating parameters on the grain size and smoothness of Ni film on silver seed layers has been studied. The duty cycle, frequency, bath temperature and agitation methods have been tested. The objective was to form a thin continuous hard etch mask (20-30 nm of thickness) of Ni films for image reversal of thin film resist using electroplating. While nickel sulfamate solution without additives or brighteners has been used to plate Ni films, reactive ion etching (RIE) has been used to test the durability of the plated Ni films in fluorine plasma. It was found that pulse reversal plating with current intensity of 12 mA/cm², duty cycle of 90%, bath temperature of 45 °C, ultrasonic agitation of power 80 W, and 400 kHz wave frequency resulted in a plating rate as low as 0.2 nm/s. This plating rate made the control of the film thickness an easy task to achieve. This yielded to a smooth plated surface free from defects or voids, with 25 nm film thickness. Combining electron beam lithography with pulse reversal plating for image reversal and RIE offers the prospect of patterning patterns with the desired aspect ratio. Holes of 100 nm diameter, 250 nm period, and 300 nm depth are achieved using this process.     

脉冲参数对高强奥氏体焊丝MIG焊接熔滴过渡的影响

采用高速摄像技术和汉诺威弧焊分析仪研究了脉冲频率、基值电流、脉宽比以及脉冲波形对H08Cr18Ni27Mo6奥氏体焊丝MIG焊接熔滴过渡的影响,结果表明,脉冲频率、基值电流与脉宽比对熔滴过渡影响较大,而脉冲波形影响较小,采用较高脉冲频率、较小的脉宽比并结合适当的基值电流能够获得理想的熔滴过渡形式。     

Optical performance of a burst-mode multikilowatt CO(2) laser

A unique advancement in the flexibility of high-power lasers is presented. Operation of a 20-kW, continuous-wave, CO(2) laser with a burst excitation technique produces a broad range of optical output characteristics. A detailed discussion of the discharge excitation of this system demonstrates some unique features of the process. Control of burst frequency and duty cycle provides a convenient means to alter the time-varying nature of the output beam. Laser output can be varied from distinct, independent pulses through to a continuous wave. Optical pulse shape varies from triangular to square in profile. The primary focus of this study lies in the regime with distinct, separate pulses. Empirical relationships that summarize the dependence of optical duty cycle and peak laser power on discharge control parameters are developed. Use of these relations imparts control of the optical parameters of importance in deep penetration welding.     

铝在硫酸银溶液中的脉冲电解着色工艺

目前,脉冲电源在铝合金微弧氧化方面应用较广,而在传统氧化着色领域应用较少。采用数控脉冲电源在硫酸银溶液中对铝进行电解着色,探讨了脉冲电解着色工艺参数对着色速度和膜层颜色的影响。结果表明:在着色溶液浓度和着色时间不变的条件下,脉冲电解着色工艺参数为工作频率50 Hz,总占空比30%,正占空比30%,反占空比70%,正向电压13 V,反向电压14 V时,膜层颜色与白色相比具有最大的色差值,着色速率最大。     

电参数对Mg-7Gd-5Y-1.5Nd-0.5Zr镁合金微弧氧化膜的影响

针对Mg-7Gd-5Y-1.5Nd-0.5Zr高强耐热镁合金,采用微弧氧化工艺制备了表面防护层,研究了电流密度、电压、频率以及占空比等电参数对膜层厚度及形态的影响规律.研究表明,电压对氧化膜厚度影响显著,电流密度对氧化膜厚度有影响但不显著,占空比和频率对氧化膜厚度影响较小.随着电流及电压的增加,膜层表面微孔的尺寸逐渐增大;随频率和占空比的增加,膜层表面微孔的尺寸先增大后减小.     

Cu2+-TiO2/蒙脱石自净化功能材料的制备及性能研究

以蒙脱石为载体,通过溶液离子交换以及高温灼烧的方法,将具有抗菌活性的Cu2+固载到载体的孔道中,同时将具有光催化降解自净化功能的TiO2插入到硅酸盐的层间。得到了对大肠杆菌(8099)和金黄色葡萄球菌(ATCC6538)抗菌率为99.99%、光催化降解亚甲基蓝溶液的净化率为92.65%的自净化功能基元材料Cu2+ TiO2/蒙脱石(Cu2+ TiO2 M)。     

The effect of pulse parameters in electro deposition of silver alloy

Pulsed electro deposition of silver alloy is aimed at the improvement of some properties like finer grain size, hardness, anti-tarnishing, lower porosity, improvement in surface property. The pulsed electro deposition of silver alloy has been analyzed from an alkaline cyanide bath with brightener. Pulse duty cycles of 20% to 80%, at frequencies 10 Hz, 25 Hz, 50 Hz and 100 Hz with peak current densities ranging from 1 A/dm² to 9.3 A/dm² are employed. The influences of pulse duty cycle, peak current density and pulse frequency on the thickness, hardness of silver deposit, and current efficiency of the plating process are studied. Good quality deposits (less porosity and fine grains) can be obtained at lower peak current density and higher duty cycle.     

导电SiC泡沫陶瓷在净化柴油车尾气中的作用

用具有三维连通网状结构的导电SiC泡沫陶瓷作为净化柴油车尾气中CO和HC的催化剂载体.模拟计算了气体通过泡沫陶瓷的过程,研究了电功率、脉冲占空比对模拟柴油机排气中HC和CO转化效率的影响和电加热时催化剂的起燃温度特性.结果表明:导电SiC泡沫陶瓷的三维结构能增加尾气与催化剂的接触几率,电加热能有效地提高反应气体的温度,从而提高了排气较低温度下HC和CO的转化效率.脉冲电流比连续电流使导电SiC泡沫陶瓷具有更强的电加热能力,并且加热能力随着脉冲占空比的减小而增强.