添加剂和电流密度对镍钴合金电铸层组织结构的影响

研究了添加剂、电流密度对镍钴合金电铸层应力和钴含量的影响。采用SEM、能谱仪和X射线衍射分析了添加剂和电流密度对铸层形貌及微观结构的影响。结果表明:添加剂TN2能够使铸层产生压应力;TN3能够使铸层产生张应力,TN3与TN2配合使用,能够使铸层应力达到平衡值零。电流密度增加时,当电流密度小于6A/dm2时,铸层应力随之增加;当电流密度大于6A/dm2时,铸层应力随之减小。添加剂对铸层钴含量影响不明显而电流密度对铸层钴含量的影响较明显;TN2,TN3的加入能够使铸层更平滑、晶粒细致紧密。添加剂TN2对衍射峰(200)影响较大,对晶面具有一定的选择性;添加剂TN3对晶面具有较强的选择性,易在(200)面吸附,抑制其生长,此时晶体的生长方向主要为[100]。随着电流密度的增大,衍射峰出现宽化的趋势。     

机械镀锌层的结构分析

运用金相显微镜、扫描电镜、能谱分析等研究了机械镀锌层的断口形貌和化学成分。结构分析表明，机械镀锌层不是扁平状锌粉的层层镶嵌叠加，而是尺寸大小不同的锌粉颗粒相互填充堆积；镀层中只有少部分锌粉颗粒发生塑性变形，并且变形取向也无明显的规律。化学成分分析表明，镀层中存在“先导金属”，“先导金属”存在于锌粉颗粒的间隙之中。     

鳞片状在环氧富锌底漆的研究

比较了鳞片状锌粉和普通球状锌粉的特点及应用原理;对比了以片状锌为诉环氧富锌底漆中状锌与其他片状颜料及防蚀颜料联合应用的效果。     

低氰仿金电镀新工艺

镀液中采用了新的次级络合剂和添加剂,阳极溶解性能良好、允许电流密度高、在规定的阴极电流密度下电镀5分钟后镀层仍然光亮.     

陶瓷膜分散法制备花瓣状碱式碳酸锌

将陶瓷膜与直接沉淀法相结合构成膜反应器,在室温条件下快速制备出三维花瓣状纳米结构碱式碳酸锌粉体.考察了陶瓷膜孔径、膜分散速率以及沉淀反应条件等对碱式碳酸锌粉体形貌的影响,采用XRD、SEM、BET、粒径分析仪等对粉体进行表征.结果表明,随着膜孔径和膜分散速率的减小,粉体粒径减小;粉体粒径随搅拌速率增大,先减小后增大.反应物摩尔配比R(MNH4HCO3/Mzn(CH3COO)2)及乙酸锌的初始浓度对粉体形状影响显著,当R由8变化到2时,粉体结构由块状变为条状,再到微球状;当乙酸锌浓度由0.25 mol/L增大到1.0 mol/L时,粉体结构由片平向哑铃状再到花辩状转变.三维花瓣状结构的碱式碳酸锌粉体粒径约3μm,由厚度约20 nm纳米片组装而成,比表面积达到61.62m2/g.     

添加剂及电源波形对镍钴合金电铸液分散能力的影响

通过正交试验研究了添加荆TN1、电源波形(全波、半波、直流)、电流密度和pH值对镍钴合金电铸液分散能力的影响.结果表明,添加剂TN1的加入可以很大程度地提高分散能力;电源渡形为全波时分散能力最好.添加剂TN1提高分散能力的原因主要是提高了阴极极化和降低了高电流密度区的电流效率;电源波形影响铸液分散能力主要是由于它对溶液导电性和电流效率有影响.添加剂和波形对分散能力的影响实质上是对双电层影响的结果.     

聚乙烯亚胺添加剂对碱性镀铜电沉积行为的影响

为了研究碱性镀铜中添加剂对铜电沉积行为的影响,采用一种新型柠檬酸碱性镀铜工艺制备了铜镀层,研究了聚乙烯亚胺添加剂在新型柠檬酸盐碱性镀铜中的作用机理.运用SEM,XRD和电化学方法对镀液、镀层进行了分析.结果表明:聚乙烯亚胺有利于获得较宽的电流密度范围和均匀细致的镀层,使铜镀层表现出(111)晶面的择优取向,铜的沉积为侧向生长;聚乙烯亚胺优先吸附在阴极高电流密度处,并对铜沉积产生较强的阻化作用;铜电沉积的初期行为服从扩散控制和三维连续成核方式生长规律.     

温度和搅拌对甲基磺酸亚锡电镀亚光锡的影响

为提高甲基磺酸盐体系镀锡的质量,在甲基磺酸亚锡镀液中加入自主研发的亚光添加剂进行电镀亚光锡,采用电化学试验、Hull槽试验、扫描电镜等考察了温度和搅拌对甲基磺酸盐体系电镀亚光锡的阴极极化行为、镀层形貌、电流密度范围、沉积效率、沉积速度及镀液成分的影响。结果表明:亚光添加剂能够显著提高电镀亚光锡的阴极过电位、改善镀层质量;搅拌镀液可使浓差极化减小,增大了电镀亚光锡的电流密度范围;镀液温度升高,锡沉积电位正移,晶粒变粗,电流密度范围、电流效率和锡沉积速度均有所提高;温度过高(40～50℃)时,随着电镀时间的延长,镀液中Sn2+浓度升高,甲基磺酸浓度下降,镀液成分变化较大,不利于镀液维护及连续生产。     

PEDOT∶PSS改性锌粉对冷涂锌涂层防护性能的影响

采用聚3,4-乙烯二氧噻吩：聚苯乙烯磺酸(PEDOT：PSS)对锌粉进行表面改性,在3.5%(质量分数)NaCl溶液中的浸泡试验和扫描电子显微镜分析结果显示改性后锌粉腐蚀减弱,扫描振动电极技术测试(SVET)结果显示腐蚀电流密度下降一个数量级,锌粉的耐蚀性得到提高。通过盐雾试验和电化学阻抗谱测试表征了锌粉改性对涂层防护性能的影响,发现改性后涂层表层锌粉消耗降低,腐蚀产物减少,且涂层的阴极保护作用时间延长20%。PEDOT：PSS提高了涂层表层中锌粉的耐蚀性和强化了涂层内部阴极保护作用。     

酸性镀铜添加剂对电沉积循环伏安曲线成核环的影响

金属电沉积的循环伏安(CV)曲线上的成核环可以用于分析添加剂对电沉积的影响及其作用机理。以常用的3种酸性镀铜添加剂为例,探讨了不同添加剂下成核环的形成特点,并从其成核环的位置以及构成成核环的电流曲线来探讨添加剂对铜沉积的影响及其机理。结果表明:当成核环分别位于不加添加剂的阴极电位和阳极电位方向时,添加剂对金属电沉积分别具有阻化和促进作用;阴极扫描方向电流密度Jb和回扫的阳极电流密度Ja是CV曲线成核环的两个特征参数,添加剂作用下的Ja和Jb与不加添加剂的接近,表明添加剂通过吸附-脱附机理影响金属的沉积,反之表明添加剂在电极表面参与化学反应。     

微乳液法制备纳米氧化锆粉体的研究

以可溶性锆盐(ZrOCl2·8H2O)-十六烷基三甲基溴化铵(CTAB)-正丁醇(C4H10O2)-环己烷(C6H12)组成的微乳液体系为基础、氨水作沉淀剂,在微乳区反应,经过洗涤、焙烧等工序,制备得到粒径10～40nm、形貌可控、分散性良好的ZrO2粉体.通过扫描电镜(SEM)、热分析仪(TG-DSC)以及X射线衍射分析对粉体进行表征,得到了晶相随焙烧温度的变化规律,并通过激光粒度仪以及Scherrer公式计算出粉体的粒度,从而得出粉体的粒度随浓度、溶水量以及焙烧温度的变化规律.     

Structural and textural study of electrodeposited zinc from alkaline non-cyanide electrolyte

Pulse electrodeposition was used to produce zinc deposits from an alkaline non-cyanide electrolyte with additives. The influence of additives’ concentration and pulse parameters, such as ON-time, OFF-time, and pulse peak current density on the grain size, surface morphology, and crystal orientation were investigated. In an additive-free electrolyte, increase in OFF-time at constant ON-time and peak current density decreases the grain size while the latter increases with increasing ON-time at constant OFF-time and peak current density. A progressive decrease of grain size was observed with increasing peak current density up to 5 Adm⁻² at constant ON-time and OFF-time in both additive-free electrolyte and bath containing additives. Zinc with an average crystallite size of 34 nm was obtained at 5 Adm⁻² from electrolyte containing additives. The preferred orientation of the zinc deposits obtained at 6 ms (ON-time), 51.5 ms (OFF-time) and 5 Adm⁻² (peak current density) with electrolyte containing additives was prismatic [10.0] plane.     

气流磨粉磨超细矿渣粉的粉体性能和微观形貌研究

煤炭、粉煤灰及矿渣是用于水泥生产的原料或混凝土的掺合料,而细度是影响粉体材料性能的因素之一。本文以矿渣为材料,利用JFC-5对撞式流态化床气流磨制备了超细矿渣粉,对超细矿渣粉的粉体性能和微观形貌进行了研究。研究表明,气流磨粉磨超细矿渣粉存在粉磨平衡,超细矿渣粉颗粒分布集中,分选机转速过大,得到的矿渣粉体出现团聚现象。     

快速电沉积法制备镍基金刚石复合镀层EI北大核心CSCD

为解决镍基金刚石复合电沉积过程中普遍存在镀层沉积速率慢、镀层内应力大的问题,本工作以新型高速Ni镀液为基础,考查了镀液中去应力添加剂含量、工艺参数,以及金刚石含量对镀层内应力影响的规律,并对复合镀层的微观形貌进行了表征。优选出了可以在30A/dm2的高阴极电流密度下快速电沉积低应力镍基金刚石复合镀层的镀液组成及工艺条件。结果表明：当镀液组成为十二烷基硫酸钠0.5g/L,乙酸铵3g/L,柠檬酸三钠1.5g/L,金刚石微粒浓度30g/L;施镀条件为pH值3~4,温度50℃时,制得的复合镀层内应力最低。     

The effect of chelating agents on the cathodic polarization and the electrodeposition of iron powders

The electrodeposition of iron powders from different baths containing the same major chemical constitutents was studied. The baths were mainly based on aqueous dilute solutions of ferrous sulphate and additives such as oxalic and citric ions. The effect of these additives on the cathodic polarization curves, current efficiency and powder morphology of the electrodeposited iron powders was investigated. It was found that electrodeposition systems with chelating agents were more polarized than a non-chelated system and produced finer powders with no dendrites.     

Electron field emission studies on ZnO nanowires

The zinc oxide (ZnO) nanowires with different morphology and diameter were synthesized on silicon (100) substrates by heating pure zinc powder at low temperatures of 450 °C and 480 °C. Scanning electron microscopy (SEM) was used to analyze the morphology and diameter of samples. The electron field emission properties between different morphology of ZnO nanowires samples were compared. A low turn-on field at 3.6 V/μm was observed from nanorods due to better alignment, and a strong emission current density of 3.6 mA/cm² at electronic field 9.0V/μm was obtained from needle-like nanowires sample. The emission stability of ZnO samples is also presented.     

石墨粉化学镀铜工艺的研究

在石墨粉表面化学镀铜,以解决金属-石墨复合材料制造中的界面结合力问题并提高其综合性能.由于石墨粉具有微小疏水、表面惰性的性质,对其镀铜很困难.以CuSO4为主盐,锌粉为还原剂,分别研究了4种添加剂:A(烷基苯磺酸盐)、B(烷基磺酸盐)、C(十二烷基脂肪酸盐)和D(十二烷基脂肪酸盐 醋酸钠)对石墨粉镀铜的影响.结果表明,D型添加剂最有利于石墨粉化学镀铜;扫描电镜观察镀铜石墨层发现,镀层和石墨结合良好.     

Sintering of ultrafine SiC powders prepared by plasma CVD

Ultrafine SiC powders with a nanometre particle size were synthesized by r.f. plasma chemical vapour deposition (CVD) using a chemical system of SiH₄−C₂H₄−Ar. The powder was also ultrapure with a grade of 99.999% purity. The product was polytype 3C−SiC and black in colour, in spite of its high purity, because of its ultrafine size. Silicon carbide is a difficult ceramic to sinter; it is possible to sinter it to full density with the aid of sintering additives. Ultrafine and ultrapure SiC powders were hot-pressed without sintering additives in the present study, in order to investigate the sintering behaviour. The CVD powders proved sinterable to 88% theoretical density without sintering additives. The present experiments revealed that powder treatment before firing was a key technology when using ultrafine powders as starting materials in the sintering process. The sintering behaviour of the powder was characterized by a large shrinkage. Phase transformation was negligible after hot pressing at 2200°C for 30 min.     

电子陶瓷用碳酸锶粉体制备与机理研究

以氯化锶和碳酸钠为原料,采用共沉淀法通过添加晶形控制剂YH-1制备出了晶形近于完美的球状超细碳酸锶粉体,利用SEM和XRD对其进行了表征。结果表明:当YH-1的用量为100%时,所制备的球状碳酸锶粒子平均粒径约为0.8!m且具有结晶完整、粒度均匀和分散性良好等优点,分析认为这可能是由于YH-1对构晶阳离子Sr2+的均匀性包裹而造成的。     

电沉积法制备ZrO_2薄膜的工艺研究

研究了水溶液中电沉积ZrO2薄膜的工艺,系统分析了镀液成分、pH值、电流密度及沉积时间对电沉积ZrO2薄膜的影响规律,并分析了薄膜的厚度、成分和形貌等。研究结果表明,在硝酸锆水溶液中加入一定量的络合剂和添加剂,可以得到与基体结合好、分布均匀的ZrO2薄膜。