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1.
刷镀镍-磷镀层的生长模型研究   总被引:1,自引:1,他引:0  
罗建东  曾德长  张弢 《表面技术》2009,38(6):6-8,75
以目前应用最广泛的刷镀镀层之一——镍一磷镀层为对象,利用自制多功能刷镀电源、原子力显微镜等设备,测得了刷镀时间与刷镀电流之间的关系,通过数据处理求得了二者之间的函数关系,在此基础上进一步求得了电流密度(刷镀电流/刷镀面积)与刷镀时间之间的函数关系;利用原子力显微镜测得镀层界面处、接近界面处和远离界面处的镀层颗粒形貌,结合刷镀电流密度与刷镀时间之间的关系,建立了刷镀镀层生长的模型。模型具有重要的指导意义:根据所建立的模型可以控制镀层颗粒的大小,改善镀层质量,为实际生产提供参考和指导。  相似文献   

2.
通过数字化均流技术并联多台等离子切割电源,增大整套系统的切割电流,提高切割能力,进行厚板等离子切割。研究了一种大功率等离子切割电源系统,采用数字化处理芯片STM32F405RGT6为核心搭建等离子切割电源控制系统,实现等离子切割电源的全数字化控制。利用数字化平均电流算法,实现电源并联的均流控制,保证单台电源输出稳定均一电流。对研制的厚板等离子切割系统进行均流测试和厚板等离子切割试验。结果表明,所设计的等离子切割电源并联切割时电源工作稳定,电流均流分布,割缝质量较好。  相似文献   

3.
增量型PID恒流恒压控制的Plasma-MIG复合电弧焊接   总被引:2,自引:1,他引:1       下载免费PDF全文
Plasma-MIG复合电弧焊接对电源的外特性输出及焊接过程控制有着很高的要求,以VC++软件开发工具为平台,推导了适合于Plasma-MIG复合电弧焊接的增量型PID控制算法,实现了对复合电弧焊接过程控制及电源外特性的要求.结果表明,增量型PID恒流恒压控制能够满足Plasma-MIG对电源外特性的输出要求.Plasma电弧和MIG电弧并不是相互独立的,两者以共享的电磁空间、导电气氛和焊丝为媒介建立起耦合关系.Plasma-MIG复合电弧焊接过程中,增量型PID控制下的Plasma电弧能够自发的调节自身电参数,来稳定电弧空间的电流密度,使得焊接过程中无飞溅.采用控制后,Plasma-MIG复合电弧焊焊接过程焊缝铺展好,焊接过程稳定,焊缝成形好.  相似文献   

4.
The non-uniformity of electroformed layers directly affects the mechanical properties and application requirements of micro devices. Therefore, uniformity of electroformed copper foil is significant in ensuring or improving the mechanical properties of micro devices. The influences of duty cycle, current density, power source, and electroforming time on the thickness uniformity of electroformed copper layers were studied, and these parameters were optimised by using the orthogonal experiment method. The thickness distribution rule of electroformed copper foil was also determined. Duty cycle had the largest influence on the uniformity; the uniformity of electroformed layers prepared with pulse reverse current power source was superior to those prepared with direct current power source and pulse current power source. Increasing current density enhanced uniformity. The optimal technical process suggested by this orthogonal experiment adopts pulse reverse current power, 30% of positive duty cycle, 10% of negative duty cycle, 2?A?dm?2 of current density, and 92?minutes of electroforming time. The minimum coefficient of variation reached 1.54%. The thickness of electroformed copper foil varied directionally.  相似文献   

5.
推力磁轴承是磁悬浮系统的重要组成部分,主要用于控制转子的轴向位移。设计获得质量轻巧、损耗较低、性能良好的推力磁轴承是工程中追求的目标。在考虑轴承承载力、温升及磁密限制等约束情况下建立了寻求轴承最优质量的目标函数,利用相应的求解方法获得了轴承的最优结构参数。同时对优化模型进行了有限元分析,得到不同频率下气隙磁密、涡流损耗等参数,揭示了不同工作条件下涡流的影响程度。  相似文献   

6.
洪波  潘应君  张恒  张扬 《表面技术》2015,44(9):23-28
目的优化钼表面直流磁控溅射镀镍薄膜的工艺,提出后续热处理方法。方法设计正交实验,探究溅射功率、溅射气压、负偏压和沉积时间对镍薄膜沉积速率和附着力的影响,从而优化工艺参数。利用扫描电镜和平整度仪对最佳工艺参数下制备的薄膜的组织结构进行表征,并研究后续热处理对薄膜附着力的影响。结果工艺参数对镀镍薄膜沉积速率影响的主次顺序为:功率溅射气压负偏压;对薄膜附着力的影响主次顺序为:负偏压沉积时间功率溅射气压。随溅射功率增大,沉积速率增大,薄膜附着力先增后减;随溅射气压增大,沉积速率和薄膜附着力均先增后减。负偏压增大对沉积速率影响较小,但有利于提高薄膜附着力。随沉积时间延长,薄膜附着力降低。在氢气气氛下进行850℃×1 h的后续热处理,能够促进扩散层的形成,明显提高镍薄膜的附着力。结论最佳镀镍工艺参数为:溅射功率1.8 k W,溅射气压0.3 Pa,负偏压450 V,沉积时间10 min。在该条件下制备的镍薄膜厚度达到1.15μm左右,与基体结合紧密,表面平整、连续、致密。后续增加热处理工序是提高镍薄膜附着力的有效方法。  相似文献   

7.
In laser+P-GMA hybrid welding,laser-wire distance is an important parameter to describe the distance from laser spot to the center of the pulsed gas metal arc.The experiments results show that the optimal laser-wire distance with the deepest weld penetration increases with welding current and laser power being increased and decreases with welding speed being increased.Welding current,laser power and welding speed determine the hybrid welding heat input in laser+arc hybrid welding process,so there is a correlation between the optimal laser-wire distance and the hybrid heat input welding parameters for the deepest weld penetration: the optimal laser-wire distance increases with the heat input being increased.The positive correlation between the optimal laser-wire distance and the hybrid welding heat input is induced by the characteristics of the limited influence of P-GMA welding process on laser transmission and the dependence of weld penetration of hybrid welding on laser power.  相似文献   

8.
Based on the program developed to simulate the temperature field for ISM(Induction Skull Melting)process, the effects of power increasing rate and charge mass on the melting throughout time and the energy consumption for TiAl alloys were studied. The results show that the melting throughout time decreases exponentially with the increasing of the power increasing rate and it linearly increases with the increasing of the charge mass. There is a critical power increasing rate for different charge masses. At this critical power increasing rate, the charge can be molten when the melting power just reaches 300 kW. There exists an optimal power increasing rate, i.e. 1.3 kW/s. At the optimal power increasing rate, the energy consumption for melting the charge is the minimum. The charge mass has noticeable influence on the energy consumed by unit mass and the ratio of effective energy.  相似文献   

9.
郑兵  王慧钧  王其隆 《焊接学报》1996,17(3):150-155
对同步方波交流电源(SYNCROWAVE-300(S)方波交流电源)的负半波时间随总电流增加而增加的原因进行了详细的试验研究和理论分析。结果表明:这种陡降特性的可控硅-电抗器式的交流电源的总电流的增加必须通过增加负半波的时间才能实现。这将会造成铝合金交流TIG焊和等离子弧焊在大电流焊接时钨极严重烧损,降低电弧和焊缝成型的稳定性。该结论不但对更好地理解可控制硅-电抗器式方波交流电源的工作原理有重要的  相似文献   

10.
目的 在高世代薄膜晶体管(Thin Film Transistor, TFT)产线的栅极刻蚀制程,明确大气压等离子体(Atmosphere Pressure Plasma, APP)清洗功率、清洗时间及刻蚀时间对刻蚀性能(关键尺寸偏差、均一性、坡度角)的影响规律,并获得最佳工艺条件,进而提升良率。方法 以APP清洗功率、清洗时间和刻蚀时间为影响因素,以关键尺寸偏差(CD Bias)、均一性、坡度角作为因变量,开展正交试验,明确因素影响重要性顺序;然后,对Cu电极坡度角的形成和刻蚀均一性变化进行分析;最后,采用回归分析获得刻蚀性能与刻蚀时间的函数关系式。结果 结果表明:刻蚀时间对刻蚀性能的影响最大,对APP清洁时间和功率的影 响较小。刻蚀时间延长,关键尺寸偏差(CD Bias)增加、均一性变差、坡度角变大。为改善均一性和平缓坡度角,应缩短刻蚀时间。最佳工艺组合为:刻蚀时间85 s,APP电压9 kV,APP传输速度5 400 r/min。结论 刻蚀时间延长,未被光刻胶覆盖的Cu膜层被完全刻蚀,形成台阶,该台阶使刻蚀液形成回流路径。沿着回流路径,刻蚀液浓度、温度逐渐下降,刻蚀均一性由此恶化,坡度角因此增加。采用回归分析得到的刻蚀性能与刻蚀时间的函数关系式,为预测刻蚀效果和优选刻蚀时间提供了依据。  相似文献   

11.
采用分段线性控制方法控制含多级液压缸的大型液压举升系统时,由于加速度不连续,易在举升过程中产生较大冲击。为消除举升过程中多级液压缸换级碰撞带来的液压冲击,提出了采用分级规划的策略。对每一级进行轨迹规划时,为保证举升过程的平稳性,采用B样条函数对举升负载的轨迹进行规划。在综合考虑工程实际中的液压系统压力、流量及负载横向过载约束的基础上,建立了举升系统的时间最优轨迹规划模型。针对解析法计算多级液压缸的最大速度和驱动力困难等问题,通过引入罚函数,提出一种改进的粒子群优化算法求解时间最优轨迹规划模型。含二级液压缸的某大型液压举升系统的仿真结果表明,提出的分级规划策略和时间最优轨迹规划方法是有效的。  相似文献   

12.
A new detection method has been presented of stray current field interference on underground metal structures. The method employs short time Fourier transformation (STFT). This method of analysis allows determination of signal spectral power density changes (e.g., structure potential) in the function of time. In the paper results have been presented of total time-frequency analysis of a pipeline potential in a stray current field generated by a tram traction. The presented results have unequivocally shown that the described method allows accurate identification of the stray current source and determination if it interacts with the underground metal structure.  相似文献   

13.
Dry electrical discharge machining (EDM) is an environmentally-friendly alternative of die-sinking EDM process, which it uses gaseous medium instead of liquid as a dielectric. Due to contribution of too many parameters in this process, selection of optimal parameters to increase the process performances is a really crucial concern. In this work, a predictive model based on back-propagation neural network has been applied to correlate the inputs and outputs of dry EDM process. Herein, the inputs were gap voltage, pulse current, pulse on time, duty factor, air intake pressure and rotational speed of tool, and also the main outputs were material removal rate (MRR) and surface roughness (SR). Firstly a back-propagation (BP) and radial basis function neural network have been developed based on data generated from literature [Saha and Choudhary Int J Mach Tools Manuf 49:297?C308 (2009)]. Then, the accuracy of proposed models has been checked by their values of error percent via testing data. Hereafter, the most accurate model was served as an objective function to optimize the process using artificial bee colony (ABC) algorithm. In optimization stage, firstly a single objective optimization was fulfilled to determine the optimal factors related to each output separately. Then a multi-objective optimization was implemented to calculate the best solutions in the case of higher MRR and lower SR simultaneously. Results indicated that the predictive model can estimate the dry EDM process precisely, and also the ABC algorithm could find the optimal solution sets logically.  相似文献   

14.
EXPERTOPTIMIZEDCONTROLTECHNIQUEFORELECTROLYTICDEPOSITIONPROCESSOFHYDROMETALLURGYOFZINC①YangChunhua,GuiWeihua,YeWenwuInformati...  相似文献   

15.
目的为提高电铸自支撑金刚石-镍复合膜的生产品质,研究一种改进的响应曲面模型,对电铸工艺的多响应参数进行优化选择。方法以电铸自支撑金刚石-镍复合膜沉积工艺参数为研究对象。在逐步回归的基础上,利用响应曲面法构建因子与响应间回归模型,通过试验设计的分析方法解释、分析、检验模型的优劣。以响应预测能力指数为权重,加权得到综合回归模型,将多响应参数优化转换为单响应参数优化,使参数优化结果优先优化预测能力强的响应,改善工艺参数整体优化效果。最后,以综合回归模型为目标函数,利用有约束最小化函数法在区间范围内搜索最优参数组合,并给出参数改进的方向。结果利用有约束最小化函数法搜索得到的最优参数组合为:金刚石含量16 g/L、阴极电流密度0.6 A/dm2、沉积时间1.5 h。通过试验设计的分析方法给出参数进一步改进的方向:在金刚石含量大于16 g/L、阴极电流密度小于0.6A/dm2、沉积时间小于1.5 h的区域内增加试验设计,以得到更优参数组合。结论将质量工具、质量改进方法及统计分析方法等运用到材料制备工艺中,能够提高最优工艺参数选择的有效性,减少试验设计的盲目性,以及达到参数全局最优的可能性。  相似文献   

16.
目的探讨不同优化算法下HT250基体再制造工艺参数的优化效果。方法利用Taguchi试验设计方法设计4因子3水平共18组试验,通过亚激光瞬间熔技术修复HT250基体的表面缺陷,利用响应曲面法(RSM)和BP神经网络-模拟退火算法(BPNN/SAA)对其修复过程的工艺参数进行优化,分析输入功率P,单次修复时间t,速度v和保护气体流量G等4个因素对修复后试样抗拉强度的影响,并对不同优化算法的优化效果、准确性和稳定性进行探讨。结果 HT250基体修复过程中最优工艺参数为:输入功率2960 W,持续时间0.62 s,速度6 mm/s,气体流量3 L/min。在此参数下所获取的修复试样最大抗拉强度为230.52 MPa。结论抗拉强度受输入功率P和单次修复时间t影响显著,对其他元素呈弱依赖性。BP神经网络-模拟退火算法较响应曲面法更适合对亚激光瞬间熔的工艺参数进行优化。  相似文献   

17.
为应对12 T以上的磁场影响,国际热核聚变反应堆ITER和国内CFETR装置上环向和中心螺线磁体系统已采用Nb3Sn材料;而低温下临界温度和分流温度是超导体稳定运行的重要因素,由于缺乏应变效应对临界温度和分流温度影响的研究,为此,本研究利用模拟应变作用的周期载荷,对Nb3Sn超导股线样品的临界温度和分流温度进行了测试以及数值模拟计算,分析获得扭距等作用使临界温度和分流温度随模拟应变载荷周期退化的结果。同时,推导分流温度随周期载荷变化的双对数分布模型,模型可以描述股线样品中由周期载荷导致的弯曲应变所产生的股线性能降级情况。  相似文献   

18.
Herein, chromium film was successfully synthesized by pulse-reverse (PR) electrodeposition using various anodic current time in a Sargent bath which is mainly composed of hexavalent chromium (Cr6+) and sulfuric acid (H2SO4). The correlation between anodic time during electroplating and various physical properties was investigated. The crack density, hardness, and thickness of electrodeposited chromium was decreased with an increase in anodic time for PR electroplating. The chromium prepared by PR electroplating showed higher corrosion resistance than that prepared by direct current (DC) electroplating owing to low crack density. Consequently, the optimal anodic time for PR electroplating was found to be 0.001 s based on the crack density, hardness, current efficiency, and film thickness. The results obtained suggest that this optimized process is a promising route for electroplating chromium film with low crack density and high corrosion resistance.  相似文献   

19.
Abstract

This study investigates the heat transfer efficiency of the pulsed gas metal arc welding (GMAW-P) process. The arc power and heat input were calculated from arc current and voltage measurements and the heat input was also measured with a liquid nitrogen calorimeter. The measured heat transfer efficiency for GMAW-P varied slightly over a wide range of pulse parameters, with an average value of 70%, a maximum of 72% and a minimum of 68%. Welding heat transfer efficiency based on arc power calculated as the product of average current and voltage was too high (averaging 82%), while that calculated using the product of the root mean square (RMS) of the average current and voltage was too low (averaging 61%). Both also varied significantly with pulsing parameters. Mathematical analysis shows that average instantaneous power values must be used when current and voltage vary significantly with time. The experimental differences between the average instantaneous power and the other calculated values are explained by the relative phases of the pulsed current, voltage and arc resistance waveforms.  相似文献   

20.
This paper outlines an experimental study of the TiSiN coatings deposited using a combination of direct current (DC) and radio frequency (RF) PVD magnetron sputtering (DR-PVD) on high speed steel (HSS) substrates. An L9 Taguchi orthogonal array was used to conduct the experiments for finding the optimum process parameters. Four process parameters, (1) RF power, (2) DC power, (3) nitrogen to argon (N2/Ar) gas ratio and (4) deposition time were considered. The surface structure and composition of selected coating samples were studied by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The critical load in the micro-scratch test was used as a measure of scratch adhesion. Investigations of the scratch tracks were viewed by an optical microscope. The results showed that higher scratch adhesion strength was achieved using RF power of 100 W, DC power of 500 W, N2/Ar ratio of 1:2.5 and a deposition time of 6 h. Optimization resulted in an increase of the critical load value from 827 mN to 1371 mN, signifying an improvement of over 65%.  相似文献   

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