稀土铝黄铜在NaCl溶液中腐蚀行为的研究

设计了一种无砷的HAl77-2-Re耐腐蚀铝黄铜.利用失重法、电化学测试、X射线衍射分析、扫描电镜与能谱分析等手段研究了这种稀土铝黄铜在NaCl(3.5%)溶液中的耐腐蚀性能及其腐蚀行为.结果表明:在稀土铝黄铜的腐蚀过程中,稀土参与了表面腐蚀产物膜的形成,增大了极化电阻,抑制了腐蚀的进行,提高了合金的耐腐蚀性能;与含砷铝黄铜相比,表现出了较好的耐腐蚀性能.     

稀土铝黄铜合金在NaCl+NH4Cl腐蚀液中的腐蚀行为

利用失重法、X射线衍射分析、扫描电镜与能谱分析等手段研究了Cu-Zn-Al-Ni-B-Ce合金在自来水和去离子水配置的NaCl(35g/L)+NH4Cl(26.75g/L)腐蚀液中的耐腐蚀性能及其腐蚀行为。结果表明:该合金在溶液中的腐蚀产物均主要为稀土氧化物(Ce4O7)、铜的碱式氯化物(Cu(OH)Cl)和铜氨络合物的水合物(Cu(OH)2NH3.H2O);在去离子水溶液中合金的腐蚀速率为1.60×10-3mm/a,在自来水溶液中的腐蚀速率达到了7.51×10-2mm/a;合金在两种腐蚀液中均有沿晶界腐蚀现象,合金在自来水溶液中的腐蚀产物厚度10~20μm,远大于合金在去离子水中的腐蚀产物厚度1μm左右,且经去离子水溶液腐蚀后的合金表面比经自来水溶液腐蚀后的平滑。     

硼对HAl77—2铝黄铜的组织和耐腐蚀性能的影响

利用ＸＲＤ、腐蚀磨损和冲蚀等实验手段对加Ｂ的ＨＡｌ７７－２铝黄铜组织和腐蚀性能进行了研究。实验结果表明：ＨＡｌ７７－２铝黄铜加Ｂ后，无论含Ａｓ与否，均能使之晶粒细化，硬度提高，抗腐蚀磨损和冲蚀性能得到明显改善。并确定了ＨＡｌ７７－２铝黄铜的最佳硼含量。     

含稀土HSn70-1锡黄铜的腐蚀行为研究

通过对Cu-Zn-Sn-Al-Ni-B-Mn-Sb-0.05RE和Cu-Zn-Sn-Al-Ni-B-Mn-Sb-0.1RE锡黄铜分别在NaCl(3.5%)溶液和NaCl(3.5%) NH4Cl(0.5mol/L)溶液中的腐蚀速率测定、腐蚀产物层SEM观察和XRD分析以及X射线能谱分析,研究了含稀土锡黄铜的腐蚀行为.结果表明:含稀土的锡黄铜在NaCl(3.5%)溶液中腐蚀后,腐蚀产物层薄而均匀,与基体之间的结合较好.稀土、硼等元素的添加可以明显改善锡黄铜耐Cl-腐蚀性能;在NaCl(3.5%) NH4Cl(0.5mol/L)溶液中发生了明显的沿晶腐蚀.同时,随稀土含量的增加,锡黄铜在含NH4 的人工海水介质中的耐腐蚀性能有所提高.     

柱状晶组织HAl77-2铝黄铜的力学性能与加工硬化行为

利用室温单向拉伸实验、EBSD和TEM等手段,研究了柱状晶组织HAl77-2铝黄铜的力学性能与加工硬化行为,探讨了晶粒尺寸对拉伸变形加工硬化速率和塑性变形能力的影响及其机制.结果表明,柱状晶组织HAl77-2铝黄铜加工硬化速率-真应变关系曲线第2阶段具有显著上升趋势,晶内形成平行分布的小角度亚晶界使位错滑移长度减小并阻碍位错运动是加工硬化速率上升的主要原因,不同于文献报道的等轴晶组织黄铜加工硬化第2阶段形成形变孪晶使滑移长度减小的机制.随着晶粒尺寸的增大,柱状晶组织HAl77-2铝黄铜的屈服强度和抗拉强度降低,而断后伸长率显著增大,由晶粒尺寸为2.0 mm的70.4%增大到晶粒尺寸为6.0 mm的84.4%.较高的抗塑性失稳能力和较好的晶内变形均匀性是大晶粒柱状晶试样具有更优塑性变形能力的主要原因.     

硼对HAl77─2铝黄铜的组织和耐磨蚀性能的影响

利用XRD、腐蚀磨损和冲蚀等实验手段对加B的HAl77-2铝黄铜组织和磨蚀性能进行了研究。实验结果表明:HAl77-2铝黄铜加B后,无论含As与否,均能使之晶粒细化,硬度提高,抗腐蚀磨损和冲蚀性能得到明显改善。并确定了HAl77-2铝黄铜的最佳硼含量。     

加硼HAl77－2铝黄铜的组织和力学性能

利用ＸＲＤ，ＳＥＭ和拉伸等实验手段对加硼ＨＡｌ７７－２铝黄铜的组织和力学性能进行了研究，实验结果表明：ＨＡｌ７７－２铝黄铜加硼后，无论含Ａｓ与否，均能使之晶粒细化，强度，硬度明显提高，塑性略有下降，在此基础上确定了ＨＡｌ７７－２铝黄铜的最佳硼含量．     

加硼HAl77—2铝黄铜的组织和力学性能

利用ＸＲＤ，ＳＥＭ和拉伸等实验手段对加硼ＨＡｌ７７－２铝黄铜的组织和力学性能进行了研究，实验结果表明：ＨＡｌ７７－２铝黄铜加硼后，无论含Ａｓ与否，均能使之晶粒细化，强度，硬度明显提高，塑性略有下降，在此基础上确定了ＨＡｌ７７－２铝黄铜的最佳硼含量。     

微量铟对稀土铝黄铜腐蚀性能的影响

采用失重法、X射线衍射法、电化学测试、扫描电镜等手段对比分析研究了铈铝黄铜和添加微量铟的新型铝黄铜的耐蚀性能。结果表明,铈铝黄铜的平均腐蚀速率为7.3×10-3 mm/a,新型铝黄铜的腐蚀速率为6.7×10-3mm/a。添加铟后能大幅度提高极化电阻,从而减小了腐蚀电流密度,耐腐蚀性能进一步得到提高;铟的加入改善了膜的结构,含In铈铝黄铜在NaCl(3.5%)溶液中腐蚀后表面形成了一层致密、完整的腐蚀产物膜,一定程度地抑制了脱锌;铟能减少锌的析氢反应,从而进一步抑制了黄铜的脱锌腐蚀。因此微量铟的加入可以改善稀土铝黄铜的腐蚀性能。     

HAl77-2黄铜在流动海水中的电化学行为

利用旋转圆环电极、电化学阻抗谱（EIS）和线性极化方法研究了HAl77—2黄铜在流动海水中的电化学行为。结果表明,HAl77-2黄铜在不同流速海水中呈现不同的EIS特征,静止海水中EIS呈现扩散影响的特征;流速〈4m／s的海水中,EIS大体表现为电荷传递控制的特征;流速≥4．5m／s时,EIS谱线低频部分呈现感抗弧。HAl77—2黄铜的腐蚀速率受海水流速的影响,流速≤2m／s时,腐蚀速率随着流速的增大基本上呈线性递增;流速在2m／s～4m／s范围内,腐蚀速率的变化较小;流速≥4．5m／s时,试样出现点蚀,且随着流速的增加腐蚀速率又迅速增大。     

稀土元素添加对铁基非晶复合材料腐蚀行为影响

采用工业原料经包覆剂(CaO-Fe₂O₃-SiO₂)处理制备Fe-15Mn-5Si-14Cr-0.2C非晶复合材料棒状试样,添加稀土元素Ce、Dy及Ce+Dy,通过XRD研究稀土元素对微观组织的影响;采用电化学工作站三电极体系测试试样在1mol/L的HCl及1mol/L的NaOH中的腐蚀行为。结果表明：合金在添加稀土元素的组织依然为非晶复合材料(过冷奥氏体相CFe_15.1+ 铁素体相Fe-Cr),加入1%Ce的试样在HCl及NaOH的耐蚀性均为最佳,在HCl中自腐蚀电位为-0.16205V,自腐蚀电流密度为7.6999×10^₈A.cm^_-2,极化阻值达到9.5774×10^₈Ω.cm^₂,在NaOH自腐蚀电位和自腐蚀电流密度为-0.1839V,1.7453×10^_-8A.cm^_-2,极化阻值为7.1574×10^₈Ω.cm^₂,耐蚀性远优于AISI304,是潜力巨大的耐蚀材料。     

Growth and corrosion behavior of rare earth film on hot-dip galvanized steel

1Introduction For a long time,chromate compounds Cr(VI)have been used as effective and inexpensive corrosion inhibitors for zinc and zinc coating.However,with the advent of increasing environmental awareness,the toxicity and carcinogenic nature of Cr(VI)b…     

Creep behavior of SnAgCu solders with rare earth Ce doping

Extensive testing was carried out to study the effects of rare earth Ce doping on the properties of SnAgCu solder alloys.The addition of 0.03%(mass fraction) rare earth Ce into SnAgCu solder may improve its mechanical properties,but slightly lower its melting temperature.The tensile creep behavior of bulk SnAgCuCe solders was reported and compared with SnAgCu solders.It is found that SnAgCuCe solders show higher creep resistance than SnAgCu alloys.Moreover,Dorn model and Garofalo model are successfully used...     

Effects of rare earth oxide additives on the thermal behaviors of aluminum nitride ceramics

The effects of Y₂O₃ and Er₂O₃ on the sintering behaviors, thermal properties and microstructure of AlN ceramics were investigated. The experimental results show that the sintering temperature can be decreased; the relative density and thermal behavior can be improved by adding rare earth oxide in AlN ceramics. For AlN ceramics with 3 wt.% Er₂O₃ additive, the relative density is 98.8%, and the thermal conductivity reaches 106 W·m⁻¹·K⁻¹. The microstructure research found that no obvious aluminum erbium oxide was found in AlN ceramics doped with 3 wt.% Er₂O₃, which favored the improvement of the thermal conductivity of AlN ceramics.     

Column leaching process of rare earth and aluminum from weathered crust elution-deposited rare earth ore with ammonium salts

In order to better understand the leaching process of rare earth (RE) and aluminum (Al) from the weathered crust elution-deposited RE ore, the mass transfer of RE and Al in column leaching was investigated using the chromatographic plate theory. The results show that a higher initial ammonium concentration in a certain range can enhance the mass transfer process. pH of leaching agent in the range of 2 to 8 almost has no effect on the mass transfer efficiency of RE, but plays a positive role in the mass transfer efficiency of Al under strong acidic condition (pH<4). There is an optimum flow rate that makes the highest mass transfer efficiency. The optimum leaching condition of RE is the leaching agent pH of 4–8, ammonium concentration of 0.4 mol/L and flow rate of 0.5 mL/min. The mass transfer efficiencies of RE and Al both follow the order: (NH₄)₂SO₄<NH₄Cl<NH₄NO₃, implying the complexing ability of anion.     

Dissolution behaviors of rare earth elements in phosphoric acid solutions

In order to provide practical fundamental data for rare-earth elements (REEs) recovery from phosphoric acid and to better understand REEs behavior during the phosphoric acid evaporation process, the solubilities of REEs in phosphoric acid with various concentrations of phosphorus at different temperatures were measured. A simple linear model between REEs solubility and phosphoric acid concentration is built and the experimental data are found to fit it very well (R²>0.94). Hydrogen-ion concentration is found to be the predominant factor controlling the solubility of REEs in phosphoric acid. In addition, the solubility of REEs in phosphoric acid is found to sharply decrease with increasing temperature, which can be attributed to the increase of the Gibbs energy of the REEPO₄ dissolution reaction or the restraint of the disassociation of phosphoric acid molecules owing to the elevated temperature.     

Preparation and processing of rare earth chalcogenides

Rare earth chalcogenides are initially prepared by a direct combination of the pure rare earth metal and the pure chalogen element with or without a catalyst. The use of iodine (10 to 100 mg) as a fluxing agent (catalyst), especially to prepare heavy lanthanide chalcogenides, greatly speeds up the formation of the rare earth chalcogenide. The resultant powders are consolidated by melting, pressure assisted sintering (PAS), or pressure assisted reaction sintering (PARS) to obtain near theoretical density solids. Mechanical alloying is a useful technique for preparing ternary alloys. In addition, mechanical alloying and mechanical milling can be used to form metastable allotropic forms of the yttrium and heavy lanthanide sulfides. Chemical analysis techniques are also described because it is strongly recommended that samples prepared by melting should have their chemical compositions verified because of chalogen losses in the melting step. TMS symposium on “Solidification and Powder Processing of Rare Earth Based Materials”, ASM/TMS Materials Week, Cincinnati, OH, 6–10 Oct, 1996.     

Corrosion behavior of LY11 aluminum alloy in soil

1lNTRODUCTIONAluminumanditsalloys,justlessthansteels,werewidelyusedincommunicati0nca-ble,pipelineandpowerstationandsooninsoil.Soilcorrosionexperimentsofvariousmaterialshavebeenconductedabroadsince1920,[1~3].Inourcountry,thenetworkofsoilcorrosionhavebeenbuiltsince195Os,steelandleadspecimenshavebeenburiedfr0mthen..[4'5],whilestain-lesssteelsandnonferrousmetalssince1989[6].Inthisexperiment,thecorrosionbehavi0rofLY1laluminumalloywasstudiedinneutralsoilofShenyang,Chengdu,acidsoilofShenzhen,Y…     

稀土元素对工业纯铝导电性的影响

研究了稀土元素对工业纯铝导电性的影响。结果表明：混合稀土对工业纯铝的导电性没有改善作用;在一定的数量范围内纯稀土元素镧、铈的加入,对铝的常温导电性有一定的改善作用,高温时则使电阻率略微上升。还对镧、铈降低铝常温电阻率的机理作了初步的探讨。