The Electroless Plating Ni-Fe-P Alloy and Its Voltammetric Behavior

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 ,研究了镍_铁_磷合金化学沉积条件 (pH值 ,温度及 [Fe2 + ]/([Ni2 + ]+[Fe2 + ])物质的量比 )对沉积速率和镀层组成的影响 ;并由此建立镀液稳定的最佳沉积工艺 .实验表明 ,镀液中硫酸亚铁对沉积镍_铁_磷合金有阻碍作用 (降低了化学沉积速率 ) ,造成镀层中铁含量不高 (小于 2 0 % ) ,使用循环伏安技术研究了镍_铁_磷合金的电沉积机理 .结果发现铁对次亚磷酸钠的氧化不起催化作用 ,提高镀液温度和pH值有增加沉积速率之效Electroless Ni_Fe_P alloy deposition from an alkaline bath, containing sodium hypophosphite as reducer, boric acid as buffer agent and sodium citrate as complexing agent, was investigated. To increase the plating rate and to inprove the bath stability, the deposition parameters were optimized. The effects of process parameters (pH,temperature and mole ratio of [Fe 2+ ]/([Ni 2+ ]+[Fe 2+ ]) on the plating rate and deposit composition were examined and it was found that the presence of ferrous sulfate in the bath has an inhibitory effect on the alloy deposition. As a consequence, the per_centage of iron in the electroless Ni_Fe_P alloys never reaches high values which is lower 20.0%. Using cyclic voltammetry the electrodeposition mechanism of Ni_Fe_P alloys was investigated. It was observed that the presence of ferrous sulfate in the bath decreases the deposition rate and the iron doesn′t catalyst on the oxidation of hypophosphite. However, the increase in temperature or pH leads to improving the deposition rate.作者联系地址：华侨大学材料科学与工程学院,厦门大学化学系,固体表面物理化学国家重点实验室 福建泉州362011 ,福建厦门361005Author's Address: 1.College of materials science and engineering,Huaqiao university,Quanzhou 362011, China, 2.State key laboratory for physical chemistry of solid surface,Department of chernistry, Xiamen university, Xiamen 361005, Chin

Deposition and Characterization of Electroless Nickel-Phosphorus-Boron Coatings From Acidic Bath

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。Acknowledgments The authors gratefully acknowledge Professor B.W.Mao for use of AFM facilities at her laboratory. We would also like to thank J.Tang for assistance with AFM measurements.作者联系地址：固体表面物理化学国家重点实验室!厦门大学化学系,福建厦门361005,固体表面物理化学国家重点实验室!厦门大学化学系,福建厦门361005Author's Address: State Key Lab. for Phys. Chem. of Solid Surfaces, Dept. of Chem., Xiamen Univ., Xiamen 361005, Chin

Electrochemical Codeposition of Palladium and Glucose Oixdase in the Presence of Glycine as Complexing Agent

甘氨酸和Pd(NH3 ) 2 Cl2 组成镀液 ,用于钯和葡萄糖氧化酶 (GOD)的电化学共沉积以制备金属化酶电极、UV/V光谱实验表明甘氨酸能与Pd2 + 离子发生络合作用 ,并使镀液在一定 pH范围内具有较稳定的化学组成 .伏安法实验证实甘氨酸的存在降低了Pd的沉积电位 ,有利于防止钯氢化合物的形成 .讨论了钯和GOD电化学共沉积的合适条件 .Glycine and Pd(NH 3) 2Cl 2 consist of a solution for the electrochemical codeposition of Pd and glucose oxidase (GOD) to prepare a metallized enzyme electrode. The experiments by UV/V spectroscopy show that the complexing of Pd ion with glycine can occur, which makes the plating bath has relatively stable chemical composition in a certain pH range. The voltammetric experiments indicate that the presense of glycine decreases the potential of Pd deposition ,facilitating to prevent the formation of palladium hydride. The appropriate conditions for the electrochemical codeposition of Pd and GOD are discussed.作者联系地址：厦门大学化学系!固体表面物理化学国家重点实验室,福建厦门361005,厦门大学化学系!固体表面物理化学国家重点实验室,福建厦门361005Author's Address: Dept. of Chem., State Key Lab. for Phys. Chem. of the Solid Surfaces, Xiamen Univ., Xiamen 361005,Chin

Properties of Metallized Poly-o-toluidide Membrane Modified Electrode

在聚邻甲苯胺 (POT)膜修饰电极上用电化学法沉积Pt微粒 ,由SEM与XRD表征其表面形态与晶面取向 ,同时研究异丙醇在金属化POT膜电极上的氧化行为 .结果表明 ,Pt在POT膜上的沉积呈现晶面择优取向的现象 ,况且POT质子掺杂后 ,由于电化学活性增强 ,影响了沉积铂微粒的尺寸和粒径分布 .异丙醇的电氧化可发生在POT的电化学活性区 ,当电位大于 0 .70V(SCE)时 ,POT不再呈氧化还原活性 ,异丙醇的电氧化主要在铂微粒上进行 .聚合物不仅作为铂微粒的载体而且自身参加反应 ,这种微异相催化体系需用新的模型描述The platinum particles were electrodeposited on poly(o_toluidide),POT,modified electrode,and the surface configuration and crystal orientation of Pt particles were investigated by SEM and XRD.At the same time the oxidation of isopropanol on platinized POT modified electrode was studied.The results indicate that Pt particles deposite towards preferred_orientation;moreover the increase in polymer electroactivity due to proton doping affects the dimension and graininess of deposited Pt particles.At the metallized polymer electrode the oxidation of isopropanol can occur in POT electroactive potential region,however at the more positive than 0.70 V (SCE) potential where POT loses redox activity the electro_oxidation mainly occurrs on Pt particles.It follows that the polymer not only behaves as the support of Pt particles but also participates in the reaction. Such a “microheterogeneous catalysis system" needs to be described by a new model.作者联系地址：厦门大学化学化工学院固体表面物理化学国家重点实验室!福建厦门361005,厦门大学化学化工学院固体表面物理化学国家重点实验室!福建厦门361005,厦门大学化学化工学院固体表面物理化学国家重点实验室!福建厦门361005Author's Address: Coll. of Chem. and Chem. Engin.,Xiamen Univ.,State Key Lab. for Phy. Chem. of Solid Surfaces,Xiamen 361005, Chin