稀土元素Ce对HSn62-1黄铜组织

研究了加入稀土元素Ce对HSn62-1黄铜组织的影响.利用腐蚀试验和电化学试验研究了稀土元素Ce的加入对合金耐脱锌腐蚀性能的影响.研究表明,加入稀土元素Ce明显地细化了合金的组织,使粗大的α、β板条状组织变成短小的细板条状组织.加入稀土元素Ce可以明显改善黄铜耐脱锌腐蚀性能.     

黄铜脱锌腐蚀的研究进展

描述了黄铜脱锌的优先溶解机制、溶解-再沉积机制、双空位机制和渗流机制，介绍了抑制黄铜脱锌腐蚀的方法，分析了As、B元素对抑制黄铜脱锌腐蚀的作用，并结合作者在微量稀土元素对黄铜脱锌腐蚀的影响方面的研究工作，讨论了稀土元素在提高黄铜抗脱锌能力所起的作用和最佳的添加量，这对以后的黄铜脱锌腐蚀研究工作具有很好的指导意义．     

稀土对ZHSi80-3合金组织和性能的影响

本文研究了稀土元素 (L a、Ce)对铸造铜合金 ZHSi80 - 3显微组织、力学性能和耐海水腐蚀性能的影响 ,并推荐了稀土含量在 ZHSi80 - 3合金中的最佳范围。实验证明 ,稀土含量在不超过 0 .1%的范围内 ,可以明显地细化 ZHSi80 - 3合金的显微组织 ,并提高强度指标 σ0 .2 及 σb,同时指出稀土元素对塑性指标 δ有不利的影响。文章还指出稀土的加入有利于提高该合金耐海水腐蚀性能。     

微量元素Sn、P对H70带材耐蚀性能的影响

采用等离子光谱测定两种H70带材中微量元素的含量，采用金相显微镜观察两种带材的微观组织；根据GB10199－88黄铜耐脱锌腐蚀性能测定了其脱锌的深度,采用扫描电镜观察腐蚀后样品的形貌；用失重法测定了样品在人造海水和含盐水中的腐蚀速度。结果表明：微量元素如Sn、P和细小均匀的晶粒，有利于黄铜耐腐蚀性能的提高，使合金的最大脱锌深度降低14．5％，平均脱锌深度降低5％。     

环境友好无铅铋黄铜研究进展

目前研究以铋代铅生产环境友好无铅黄铜较为常见.系统地描述了无铅铋黄铜的发展背景和国内外研究开发动态,分别介绍了铋黄铜合金成分优化、组织结构及冷热加工性能对其切削性能、耐脱锌腐蚀性等方面的影响,并对将来开发、应用环境友好无铅黄铜存在的问题及研发方向提出了几点建议.     

稀土元素Ce对铸态Cu-Si-Ni合金组织号陛能的影响

研究了稀土元素Ce的不同加入量对铸态Cu—Si—Ni合金电导率、硬度和组织的影响。研究结果表明：稀土元素Ce能净化铜基体、细化晶粒、提高cu—si—Ni合金的电导率及硬度,当稀土元素Ce的加入量为0．06％时Cu—Si—Ni合金的电导率和硬度最高。     

凝汽器铜管的耐蚀行为研究

本文就B、As、P、Ce等元素对凝汽器铜管耐蚀行为的影响进行简要阐述，并说明了它们的基本机理和目前出现的难点。结论表明，加入适量砷、硼和稀土Ce等元素，可以起到抑制黄铜冷凝管的脱锌腐蚀，相反，若用量过多，则加快其脱锌腐蚀。     

黄铜脱锌腐蚀的研究进展

阐述了黄铜脱锌腐蚀的几种腐蚀机理和砷、硼、稀土等对抑制黄铜脱锌腐蚀的影响,介绍了黄铜脱锌腐蚀的特征和金相组织。与纯铜相比,黄铜具有较高的力学性能和铸造性能,耐磨、易切削、良好的导电导热性能且低成本、易于钎焊和回收。基于这些特点,黄铜的用途极为广泛,如水箱带、供排水管、奖章、波纹管、蛇形管、冷凝管、弹壳及各种形状复杂的冲制品、小五金件等。     

硼对Cu—35%Zn黄铜耐选择性腐蚀的影响

目前在研究改善铸态加硼黄铜的耐脱锌腐蚀中,普遍都使用俄歇光谱、空穴敏感正电子烟灭测定、宏观偏析研究和脱锌试验。俄歇光谱和正电子寿命测定的结果均说明:锌原子在贫化区的迁移是由于易变动的过剩空穴强化和帮助了扩散所致,并已发现含硼黄铜耐脱锌能力改善的原因是因为硼消除了空穴。而且靠近铸锭的冷面处,出现硼的宏观反偏析。而靠近铸锭中心是宏观正偏析。这种现象随硼含量的增加而扩大。脱锌试验结果表明,合适的硼添加量能有效地改善耐蚀能力、降低腐蚀速度和表面不稳定性。     

冷却条件和Ce含量对Galfan合金凝固组织及其耐蚀性的影响

Galfan合金中的稀土元素对合金的组织和耐蚀性有显著影响。实验研究了稀土元素Ce含量(质量分数)分别为0,0.05%,0.10%和0.20%的Zn-5%Al-x Ce合金在炉冷、空冷和水冷3种冷却条件下的凝固组织及其耐蚀性,进而分析稀土元素添加量和冷却方式对Galfan合金显微组织及耐蚀性的影响。结果表明,冷却条件和Ce含量对Zn-5%Al-x Ce合金的显微组织和耐蚀性有明显影响。随Ce含量的增加,Zn-5%Alx Ce合金的层片共晶组织分布均匀,杂质、裂纹等缺陷减少。Ce元素的加入显著改善了合金的凝固组织和耐蚀性,使合金的耐蚀性先增强后减弱。此外,合金的冷却速度越大,获得的组织越致密,且耐蚀性越好。Zn固溶体呈完整树枝状,棒状,胞枝状到胞状变化。研究认为,添加0.1%Ce的Galfan合金水冷后的耐蚀性最好。     

铜基形状记忆合金在人工体液中的腐蚀行为

采用浸泡试验和电化学技术对CuZnAl形状记忆合金在人工液体中的腐蚀行为进行了研究。结果表明,CuznAl形状记忆合金的腐蚀形式为脱锌腐蚀。CuZnAl形状记忆合金的耐腐蚀性优于未经记忆效应处理的同成分合金。该合金耐蚀的原因是,由于单相马氏体组织具有记忆行为和超弹性,改善了表面电化学行为,促进了钝化,从而抑制了阳极活性溶解。     

铝合金表面稀土铈耐蚀膜

采用线性极化技术对在铝合金表面生成稀土耐蚀膜的21种工艺进行了筛选。考察了溶液浓度、温度、时间和pH值等工艺因素对成膜耐蚀性的影响.电化学测试结果表明,表面生成稀土耐蚀膜后铝合金的耐蚀性得到了显著改善,稀土耐蚀膜的存在既抑制了腐蚀的阴极过程,又抑制了阳极过程。氧、铈、铝是组成膜的3种主要元素。     

Corrosion behavior of rare earth cerium based conversion coating on aluminum alloy

The present paper focused on the use of the salt of rare earth cerium as corrosion inhibitor of aluminum by using cathodic electrolytic passivation method.The corrosion resistance and the microphology of the cerium passivation film were studied by the methods of electrochemical method,scanning electron microscopy(SEM),and energy dispersive spectroscopic analysis.From the results,it was shown that good corrosion resistance of cerium-based passive coating was obtained when the compositions were as follows:CeCl3·7H2O,0.05 mol/L;H2O2,30 ml/L;current density,1.1 mA/cm2;temperature,40 oC;time,9 min.SEM and EDS revealed that the cerium conversion coatings formed on the surface of aluminum alloy were related to cerium hydroxide/hydrated oxide depositions.     

无铅易切削石墨黄铜抗脱锌腐蚀性能的正交设计

采用粉末冶金方法,制备以石墨代替铅元素的环保型易切削黄铜。利用正交实验法,分析石墨粒度、石墨含量、烧结温度以及烧结时间对无铅易切削黄铜的抗脱锌腐蚀性能的影响。试验表明:烧结温度对无铅易切削黄铜抗脱锌腐蚀性能的影响最大,烧结时间次之。含0.1%的粒度为1.5μm石墨的易切削黄铜,在865℃下保温60 min,其脱锌腐蚀深度最小,抗脱锌腐蚀性能最佳。     

不同相组成的硅黄铜组织性能的研究

通过OM、XRD以及TG/DTA等测试技术,系统研究了(α+β)双相、单一β相以及(β+γ)双相无铅硅黄铜的组织结构、硬度、铣削性能以及脱锌腐蚀等性能.结果表明:(α+β)硅黄铜虽然铣削力较低,但切屑形态欠佳,且平均脱层厚度大,为438.12μm;而(β+γ)相硅黄铜不仅切屑形态最差,硬度最高,达273.7 HB,因而铣削力也最大,增加刀具的磨损,降低刀具寿命;β相硅黄铜虽然铣削力稍高,但切屑形态为细小卷筒状,呈最优切屑形态,且在抗脱锌腐蚀测试中,β相硅黄铜平均脱锌层厚度最小,为262.94μm,所以β相硅黄铜综合性能最佳,(β+γ)硅黄铜不适合做切削黄铜,而(α+β)硅黄铜的切削性能和耐腐蚀性能都有待改进.     

Formation and characterization of cerium conversion coatings on magnesium alloy

Chemical conversion treatment by rare earth metal salt solution was considered as an alternative to chromium chemical conversion treatment to improve the corrosion resistance of magnesium alloys. In this study, cerium conversion coatings formed on AZ31 magnesium alloy were characterized and the formation mechanism was discussed. X-ray photoelectron spectroscopy （XPS） analysis showed that cerium conversion coating consisted of cerium hydroxides/oxides, in which both tetravalent cerium Ce（Ⅳ） and trivalent cerium Ce（Ⅲ） species co-existed. Cerium conversion coating was a two-layer structure. Atomic force microscopy （AFM） images revealed that the morphology of the inside layer was different from that of the outside one, which was responsible for the inherent adhesive weakness of the coating. Corrosion potential （Ecorr） measurements indicated that poor adhesion limited the improvement of the corrosion resistance of the coating. During the treating process, the increased pH value of the cerium salt solution led to the precipitation of cerium hydroxides/oxides. The formation kinetics of the coating followed a parabolic curve.     

Corrosion behavior of rare earth cerium based conversion coating on aluminum alloy

The present paper focused on the use of the salt of rare earth cerium as corrosion inhibitor of aluminum by using cathodic electrolytic passivation method. The corrosion resistance and the microphology of the cerium passivation film were studied by the methods of electrochemical method, scanning electron microscopy (SEM), and energy dispersive spectroscopic analysis. From the results, it was shown that good corrosion resistance of cerium-based passive coating was obtained when the compositions were as follows: CeCl₃·7H₂O, 0.05 mol/L; H₂O₂, 30 ml/L; current density, 1.1 mA/cm²; temperature, 40 °C; time, 9 min. SEM and EDS revealed that the cerium conversion coatings formed on the surface of aluminum alloy were related to cerium hydroxide/hydrated oxide depositions.     

Corrosion Resistance of Reactive Element Aluminide Diffusion Coatings on a Nickel‐based Superalloy and an Austenitic Stainless Steel

Continuously cast aluminium alloy wires containing active elements such as yttrium, cerium, lanthanum or silicon were used as evaporation sources for ion vapour deposition on nickel‐based Inconel IN738 and stainless steel 310S substrate materials. The samples were subsequently diffusion heat‐treated to form protective corrosion resistant nickel aluminide and iron aluminide coatings. The coated alloy materials were exposed for prolonged periods to high temperature cyclic oxidation, molten sulphate, and molten carbonate environments to evaluate their resistance to hot oxidation. For IN738, the lanthanum‐modified aluminide coating provided good thermal cyclic oxidation performance while the cerium‐modified coating exhibited effective hot corrosion resistance in a molten sulphate environment. For 310S stainless steel, all of the modified aluminide coatings provided equally good corrosion protection when exposed to molten carbonate attack under an oxidizing atmosphere.     

Effect of cerium on microstructure,mechanical properties and corrosion properties of Al-Zn-Mg alloy

The effects of trace Ce on the microstructure,mechanical properties and corrosion resistance of Al-Zn-Mg alloy were studied by means of metallographic analysis,scanning electron microscopy(SEM),mechanical tensile test,slow strain rate tensile test,cyclic polarization curve test,electrochemical impedance spectroscopy test and anodic oxidation test.The results show that the addition of trace Ce has little effect on the strength of Al-Zn-Mg alloy,but can significantly improve the corrosion resistance of the alloy;The mechanical properties and corrosion resistance of the alloys decrease significantly with the addition of excessive Ce;the addition of 0.04 wt%Ce can reduce significantly the self-corrosive current density of AlZn-Mg alloy and increase obviously passivation film resistance of the alloy.The stress corrosion sensitivity index decreases from 0.612 to 0.219,which improves the corrosion resistance properties significantly.     

含铈304不锈钢夹杂物改性及耐腐蚀性能优化

 通过在304不锈钢中加入不同含量的铈,研究了铈处理前后钢中夹杂物的变化,并借助于腐蚀失重试验及电化学试验,分析了不同含量的铈处理后钢中夹杂物性质变化对304不锈钢耐腐蚀性能的影响。研究结果表明,未加铈的不锈钢中主要为MnS夹杂及复合氧化物夹杂,夹杂物的平均尺寸为8.6 μm,而钢的自腐蚀电位仅为-348.52 mV。加入稀土铈后,夹杂物逐渐改性成球状或椭球状的含铈夹杂物,平均尺寸有所降低,而不锈钢耐腐蚀性则有所提高。当铈质量分数达到0.012%时,钢中MnS夹杂全部改性成球状含铈夹杂,不锈钢自腐蚀电位高达-311.25 mV,耐腐蚀性能最好。继续增加稀土铈含量,钢中夹杂物的形状变得不规则,尺寸也有所增加,导致不锈钢耐腐蚀性能降低。