化学沉积NiZnP合金及其性能

用柠檬酸钠为络合剂、硼酸为缓冲剂在碱性体系中用化学沉积法由ZnSO4、NiSO4、NaH2PO2和H2BO3制得了NiZnP合金。考察了pH和ZnSO4与(ZnSO4 NiSO4)摩尔比对沉积速度、镀层组成、结构、表面形貌和耐腐蚀性能的影响。发现锌在沉积过程中起阻碍作用,致使镀层中锌含量不高(不超过原子分数20％)。用X射线衍射、透射电镜和扫描电镜等技术研究了镀层的结构和表面微观形貌。结果表明,镀态合金由非晶和少量立方镍两相组成;工艺条件对镀层表面微观形貌有明显的影响。采用浸泡实验和电化学阳极极化实验,重点研究了不同工艺条件的镀层在质量分数为3．5％的NaCl溶液(pH=7．0)中的耐腐蚀性能。结果表明,不同工艺条件所得的镀层耐腐蚀能力不同,NiZnP合金的耐腐蚀性主要与镀层组成有关,含锌量越高、含磷量越低的镀层耐腐蚀性越好。浸泡实验和电化学阳极极化实验的结果是比较吻合的。     

酸性溶液化学镀Ni-P-B合金及结构性能表征(英文)

联用次亚磷酸钠和硼氢化钠两种还原剂 ,从酸性镀液中沉积出不同硼含量的Ni_P_B镀层 ,并用原子力显微镜、X_射线衍射、透射电镜、动电位扫描等实验技术对其镀态结构及性能进行了表征。实验表明 ,镀液中硼氢化钠含量对沉积速度影响不大 ,但能显著影响镀层的化学组成。硼的共沉积使镍晶格点阵产生扭变 ,导致镀层晶粒增大 ,表面粗糙 ,颗粒分布不均匀 ,并使镀层由非晶态向微晶结构转变 ,且微晶成分随镀层中硼含量的增加而增多。Ni_P_B镀层的硬度随镀层中硼含量的增加而增大 ,热处理能显著提高镀层的硬度 ,且服从沉淀硬化机理。在 3.5wt%NaCl和 40wt%NaOH两种介质中 ,Ni_P_B合金的耐腐蚀能力优于Ni_P合金。镀层中硼含量越高 ,其耐腐蚀能力越强。     

热处理对化学沉积Ni-Fe-P合金性能的影响

采用DSC和XRD研究了化学镀Ni-Fe-P合金的晶化行为和结构.结果表明,镀态合金呈非晶结构, 367.6 ℃下热处理出现亚稳态Ni5P2(P3)和Fe-Ni(Im3m), 499.2 ℃下热处理进一步晶化为稳定的Ni3P(I-4)和FeNi3(Pm3m).采用磁性能实验和在w=3.5％氯化钠溶液浸泡实验以及阳极极化实验研究了热处理对镀层磁性能和耐腐蚀性的影响.结果表明,该镀层在镀态时几乎没有磁性,随着退火温度的升高,磁性能不断提高. 400 ℃以后,镀层的饱和磁化强度和矫顽力随着退火温度升高而急剧上升.浸泡实验和阳极极化实验结果均表明镀态镀层比经热处理后的镀层在w=3.5％氯化钠溶液中具有更好的耐腐蚀性,但是它们的阳极极化行为不同.     

硫酸亚铁对化学沉积钴-铁-磷合金中的影响(英文)

在以次亚磷酸钠为还原剂、硼酸为缓冲剂和柠檬酸钠为络合剂的碱性介质中,化学沉积钴 铁 磷合金和钴 磷合金.研究了沉积工艺,如pH值和主盐CoSO4/FeSO4的摩尔比对沉积速率的影响.发现镀液中的硫酸亚铁对钴 铁 磷合金沉积有阻碍作用,以致其沉积速率比钴 磷的低.电化学极化实验表明,硫酸亚铁既影响阳极过程又影响阴极过程,它降低了两者的极化电流和极化电势.电化学实验结果与沉积速度测量结果基本相符.     

非晶态Ni-Ce-P合金的共沉积与耐蚀性能

采用恒电位沉积、循环状安等方法研究了在水溶液中电沉积稀土合金的可能性 ,首次在含有CeCl3的弱酸性NaH2 PO2 镀液中获得了不同铈含量的Ni Ce P合金镀层 ,XPS、AES、XRD和SEM等实验技术表征了镀层的组成和结构 ,极化电阻和腐蚀电位的测试数据表明此镀层与Ni P无定形合金相比 ,具有更强的耐腐蚀能力 ,同时 ,讨论了沉积条件与镀层耐蚀性能的关系 ,结论是 :镀层中铈含量越高 ,其耐腐蚀性能越好 ,此外还对Ni Ce P的共沉积机理进行了初步探讨 ,指出在所研究的电沉积条件下 ,Ni Ce P合金共沉积可以用“诱导共沉积理论”合理解释     

2,2′-联吡啶在化学镀铜中的作用研究

研究了以次磷酸钠作还原剂的化学镀铜体系,添加剂2,2′-联吡啶对化学镀铜沉积速率、次磷酸钠阳极氧化和铜离子阴极还原、以及镀层形貌、结构和组分存在状态的影响.结果表明,2,2′-联吡啶对化学沉积起阻化作用.电化学线性伏安扫描实验显示,镀液中加入2,2′-联吡啶,次磷酸钠的氧化峰电势有所负移,但峰电流减小;铜离子的还原峰电势负移,但峰电流逐渐增大.扫描电子显微镜(SEM)、能量色散谱(EDS)、X射线衍射(XRD)及X射线光电子能谱(XPS)等实验分别表明,添加剂使镀层致密和光亮、镍含量降低;镀层为Cu-Ni合金,呈面心立方结构,无明显晶面择优取向现象;镀层中铜和镍以金属态存在,磷的质量含量小于0.05%.     

超重力场电沉积NiW合金及其耐碱腐蚀性能

在超重力条件下电沉积NiW合金镀层,考察了超重力对NiW合金电沉积过程(各元素分电流、W含量和槽电压等)的影响规律;并利用扫描电子显微镜(SEM)、Tafel技术和电化学阻抗谱(EIS)技术研究了电沉积NiW合金镀层的表面形貌和在NaOH溶液中的抗腐蚀性能,同时通过浸泡实验考察了镀层的稳定性.结果发现,与常重力条件电沉积的NiW合金相比,超重力场电沉积的NiW合金中W含量增加,镀层表面无微裂纹产生;在10%(w)NaOH溶液中镀层自腐蚀电位正移,自腐蚀电流密度减小,腐蚀电阻也由常重力(重力系数G=1)时的865Ω·cm2增大至超重力(G=256)时的2305Ω·cm2;在10%NaOH溶液中浸泡144h后,超重力场电沉积的NiW合金表面无破碎和起皮现象发生.超重力技术在NiW合金电沉积过程中的应用,使镀层的耐碱腐蚀性能得到改善.     

CO2-3对羟基乙叉二膦酸镀铜液的影响

研究羟基乙叉二膦酸(HEDPA)镀铜液中CO2-3含量对电沉积时阴、阳极过程及镀层的择优取向的影响. 通过分析阴、阳极的动电位极化曲线, 发现镀液中逐渐加入的CO2-3提高了阴极的极化, 使电结晶晶粒细化, 直至达到稳定; 同时促进了铜阳极的溶解. 而X射线衍射(XRD)结果表明, 铜镀层的晶面择优取向从(222)逐渐向(111)转变. 通过镀液中固体络合物的红外光谱分析表明, CO2-3的加入以第二配体的方式进入该镀液的放电络合离子结构中, 参与Cu2+的络合, 形成更稳定的络合物, 从而导致铜沉积电位负移, 镀层(111)晶面取向增强.     

CO2-3对羟基乙叉二膦酸镀铜液的影响

研究羟基乙叉二膦酸(HEDPA)镀铜液中CO32-含量对电沉积时阴、阳极过程及镀层的择优取向的影响.通过分析阴、阳极的动电位极化曲线,发现镀液中逐渐加入的CO32-提高了阴极的极化,使电结晶晶粒细化,直至达到稳定;同时促进了铜阳极的溶解.而X射线衍射(XRD)结果表明,铜镀层的晶面择优取向从(222)逐渐向(111)转变.通过镀液中固体络合物的红外光谱分析表明,CO32-的加入以第二配体的方式进入该镀液的放电络合离子结构中,参与Cu2+的络合,形成更稳定的络合物,从而导致铜沉积电位负移,镀层(111)晶面取向增强.     

非晶态Ni-W/ZrO2复合镀层的制备、热处理及腐蚀行为

在镍钨合金电解液中, 通过搅拌使二氧化锆固体微粒悬浮, 电沉积制备Ni-W/ZrO2复合镀层. 研究结果表明, 二氧化锆粒子影响复合镀层的电沉积、表面形貌、结构、热处理过程和抗腐蚀性能; 与Ni-W合金的电沉积过程相比, 复合镀层中的W含量和电流效率均降低; 在400 ℃处理1 h后, 嵌入Ni-W本体中的ZrO2粒子脱落, W向镀层表面富集. 扫描电子显微镜(SEM)结果显示, 复合镀层呈现团粒状形态, 无裂纹. 差示扫描量热(DSC)分析结合X射线(XRD)衍射实验指出, Ni-W/ZrO2复合镀层为非晶态结构. 复合镀层的显微硬度较纳米晶Ni-W合金的高; 热处理后, 复合镀层的显微硬度和在3%氯化钠溶液中的抗腐蚀行为显著增强.     

Electrolessly Plated Ni-Zn（Fe）-P Alloy and Its Corrosion Resistance Properties

The autocatalytic deposition of Ni-Zn(Fe)-P alloys has been carried out on substrate of carbon steel from a bath containing nickel sulfate, zinc sulfate, sodium hypophosphite, sodium citrate and boric acid. The effects of pH and the molar ratio of NiSO4/ZnSO4 on the deposition rate and the composition of deposits have been studied. It was found that the presence of zinc sulfate in the bath has an inhibitory effect on the alloy deposition. The structure and the surface morphology of Ni-Zn(Fe)-P coatings were characterized with XRD and SEM, respectively. The alloys plated under the experimental conditions consisted of an amorphous phase coexisting with a crystalline cubic Ni phase (poly-crystalline). The surface morphology of the coating is dependent on the deposition parameters. The corrosion resistance of the Ni-Zn(Fe)-P deposits was examined via mass loss tests and anodic polarization measurements, respectively. The results show that the surface morphologies of the deposits and the corrosion resistance of the deposits have been improved. The results of mass loss tests almost accord with those of anodic polarization measurements. The corrosion mechanisms of Ni-Zn(Fe)-P alloys in NaCl and NaOH solutions were investigated by means of EDX. The deposit immersed in an NaCI or an NaOH solution contains more content of oxygen and less contents of the metals(except Fe) than that placed in air, which shows that the NaCl or NaOH solution can accelerate the oxidation of the deposit.     

Fe-W非晶镀层的磷化及在NaCl溶液中的腐蚀行为

ＦｅＷ非晶态合金镀层在酸性溶液中具有高耐蚀性能,但在中性和碱性溶液,特别是在氯化钠溶液中耐蚀性能差［１］,如在３０℃、１ｍｏｌ／ＬＨＣｌ溶液中,ＦｅＷ非晶镀层的腐蚀速率约为不锈钢ＳＵＳ３０４的１／１５;在６０℃、０５ｍｏｌ／ＬＨ２ＳＯ４溶液中约...     

Effect of acidity level Ro(H) on the corrosion of steel in concentrated HCL solutions

The corrosion of a carbon steel in (0.5 – 9.0 M) HCl media using weight loss, electrochemical polarization and polarization resistance measurements was investigated. The corrosion data are discussed as function of the Strehlow acidity function R_o(H) which is the extension of pH in concentrated solutions. Weight loss, corrosion current densities and resistance polarization values show a linear behaviour with the R_o(H) acidity function. The corrosion potential-R_o(H) plot is also linear using the ferricinium (Fc⁺) / ferrocene (Fc) reference electrode in concentrated acid solutions.     

The effect of chloride concentration and pH on pitting corrosion of AA7075 aluminum alloy coated with phenyltrimethoxysilane

The effect of chloride ion concentration and pH of solution on the corrosion behavior of aluminum alloy AA7075 coated with phenyltrimethoxysilane (PTMS) immersed in aqueous solutions of NaCl is reported. Potentiodynamic polarization, linear polarization, open circuit potential, and weight loss measurements were performed. The surface of samples was examined using SEM and optical microscopy. Elemental characterization of the coating by secondary ion mass spectrometry indicates an intermediate layer between coating and aluminum alloy surface. The corrosion behavior of the aluminum alloy AA7075 depends on chloride concentration and pH of solution. In acidic or neutral solutions, general and pitting corrosion occur simultaneously. On the contrary, exposure to alkaline solutions results in general corrosion only. Results further reveal that aluminum alloy AA7075 is susceptible to pitting corrosion in all chloride solutions with concentrations between 0.05 M and 2 M NaCl; an increase in the chloride concentration slightly shifted both the pitting and corrosion potentials to more active values. Linear polarization resistance measurements show a substantially improved corrosion resistance value in case of samples coated with PTMS as compared to uncoated samples in both neutral (pH = 7), acidic (pH = 0.85 and 3), and alkaline chloride solutions (pH = 10 and 12.85). The higher corrosion resistance of the aluminum alloy coated with PTMS can be attributed to the hydrophobic coating which acts as a barrier and prevents chloride ion penetration and subsequent reaction with the aluminum alloy.     

Corrosion inhibition of 302 stainless steel with schiff base compounds

The effects of 2,2′-[bis-N(4-cholorobenzaldimin)]-1,1′-dithio (BCBD) and bis-(2-aminophenyl) disulphide (BAPD) on the corrosion behavior of 302 stainless steel in 0.5 M sulfuric acid solution as corrosive medium were investigated using weight loss and potentiostatic polarization techniques. Some corrosion parameters such as anodic and cathodic Tafel slopes, corrosion potential, corrosion current density, surface coverage degrees and inhibition efficiencies were calculated. The polarization measurements indicated that the inhibitors were of mixed type which inhibited corrosion by parallel adsorption on the surface of stainless steel due to the presence of more than one active centre in the inhibitor molecule. The adsorption followed Langmuir adsorption isotherm. The activation energy and thermodynamic parameters were calculated at different temperatures. Results showed that BCBD had a higher inhibition efficiency compared with BAPD.     

The effect of 2-aminoquinoline-6-carboxylic acid on the corrosion behavior of mild steel in hydrochloric acid

The inhibitive effect of 2-aminoquinoline-6-carboxylic acid (AQC) against mild steel corrosion in 1?M HCl solutions was investigated using conventional weight loss, potentiodynamic polarization, linear polarization and electrochemical impedance spectroscopy methods. The weight loss results showed that AQC is an excellent corrosion inhibitor since its efficiency increased with the concentration to attain 91.8?% at 500?mg?l^?1. Electrochemical polarization measurements revealed that AQC acted as a mixed-type inhibitor and the results of electrochemical impedance spectroscopy have shown that the change in the impedance parameters, charge transfer resistance and double layer capacitance, with the change in concentration of the inhibitor is due to the adsorption of the molecule leading to the formation of a protective layer on the surface of mild steel. The adsorption was assumed to occur on the steel surface through the active centers of the molecule. The inhibition action of AQC was discussed in view of Langmuir adsorption isotherm. Density functional theory calculations of quantum parameters were used to explain efficiency in relation with molecular structure.     

Electrodeposition, Structure and Corrosion Resistance of Nanocrystalline Ni-W Alloy

Ni—W alloy was electrodeposited from the electrolyte solution containing sodium tungstate, nickel sulfate and ammonium citrate. The electrodeposition, heat treatment, structure, surface morphology and corrosion resistance in w=0.03 NaCl solution, of Ni-W alloys were studied by means of DSC, XRD, SEM and electrochemical techniques. The results showed that the obtained Ni-W alloy electrodeposit with W weight content (Ww=0.471) was presented in more typical nanocrystaUine, After heat treatment at 400 ℃ for 1 h, the phase structure of the deposits was not obviously changed whereas the agglomerate for the reunion of tiny grains on deposit surface caused the granule in a more smooth morphology, the microhardness was slightly increased and the corrosion resistance was enhanced.     

深海静水压力环境下低合金高强度钢腐蚀行为研究

通过自行设计的深海环境模拟装置,采用静态挂片失重、动电位极化曲线及电化学阻抗谱（EIS）等方法系统研究了深海静水压力环境下低合金高强度钢（HSLA钢）在3.5% NaCl溶液中的腐蚀行为,并与常压下的结果对比,探讨了静水压力下HSLA钢在深海环境中的腐蚀行为. 结果显示,静水压力并没有改变HSLA钢在3.5% NaCl溶液中的腐蚀历程,不甚影响其阴极过程,而主要提高了其阳极腐蚀速率,这可能与高静水压下Cl-活性的增加有关.