复配BTA与TTA钝化纯铜工艺研究

目的为了提高纯铜表面的耐腐蚀性。方法通过苯并三氮唑(BTA)与甲基苯并三氮唑(TTA)复配,对纯铜进行钝化,并分析钝化温度、时间及pH值对纯铜钝化效果的影响。分别运用电化学法、硝酸点滴实验、中性盐雾实验、SEM等手段对不同钝化液钝化膜的微观结构与耐蚀性能进行研究,并与铬酸盐钝化结果进行对比。结果将4 g/L BTA、4 g/L TTA复配,辅以氧化剂20 m L/L H_2O_2,对纯铜以pH值为4、钝化时间3 min、钝化温度40℃、自然风干老化1 d的钝化工艺处理后,可以生成明显的钝化膜。其表面致密,耐蚀性较好,在盐雾试验中腐蚀缓慢,其平均腐蚀速率为0.76 mg/d,自腐蚀电流密度仅为1.5660μA/cm2,缓蚀率达到81.9%,接近铬酸盐钝化的抗腐蚀效果。结论在适宜的钝化工艺下,经过BTA与TTA复配钝化后,可以在基体表面生成Cu/Cu_2O/Cu(I)BTA聚合物保护膜,同时TTA的非极性甲基形成的单分子层膜的疏水性更好,两者共同作用,形成较为致密的钝化膜覆盖在铜基体表面,明显提高纯铜表面耐蚀性。     

热镀锌钢板钝化工艺对耐蚀性的影响

为提高热镀锌钢板的耐蚀性,对热镀锌钢板铬酸盐钝化工艺进行了研究.采用盐雾试验、钝化膜的微观形貌等手段分析了钝化液浓度及钝化工艺参数(钝化液温度、烘干时间、烘干温度等)对热镀锌钢板铬酸盐钝化膜耐蚀性的影响.结果表明,采用试验确定的钝化工艺处理得到的钝化膜耐蚀性明显提高,对实际生产具有较好的指导意义.     

工艺因素对硅酸盐无铬钝化中耐蚀性的影响

为了更深入地探讨硅酸盐无铬钝化中工艺因素对耐蚀性的影响,采用中性盐雾试验考察了各种工艺条件下硅酸盐钝化膜的耐蚀性,结果表明,工艺因素对钝化膜耐蚀性影响很大,而且得出了各工艺参数与钝化膜耐蚀性之间的关系.     

Effects of Electric Parameters on Properties of Micro-arc Oxidation Films Formed on Magnesium Allovs AZ91D

在铝酸盐体系中对AZ91D镁合金进行微弧氧化处理.利用田口式实验设计法探讨微弧氧化过程电参数对膜层耐蚀性的影响,确定了最佳工艺参数为:电压180V,氧化时间30 min,频率50 Hz,占空比30％.用交流阻抗分析膜层的耐腐蚀性能,结果表明:最佳工艺条件下所制备微弧氧化,膜层电阻比镁合金基体提高了2个数量级,耐蚀性有所增强.     

铜包铁粉末表面的钝化处理

通过对2种苯并三氮唑(BTA)有机添加剂复合配方和1种常用的钝化剂对比试验,探索了BTA系复配钝化剂在铜包铁粉末防变色钝化处理中的钝化效果及机理,通过硝酸滴定试验、氨水滴定试验、SO2加速腐蚀试验、大气腐蚀试验及温湿耐蚀试验,得出铜包铁粉末表面钝化的最佳工艺为:0.5%BTA,1～3g/L OP-10,温度为50～60℃,处理时间为3～5 min.BTA复配体系处理后的防护效果好于BTA单一体系,单一BTA处理后的钝化效果好于目前常用的钾肥皂钝化效果.     

AZ91D镁合金微弧氧化电参数对其耐蚀性的影响

在铝酸盐体系中对AZ91D镁合金进行微弧氧化处理。利用田口式实验设计法探讨微弧氧化过程电参数对膜层耐蚀性的影响,确定了最佳工艺参数为:电压180V,氧化时间30min,频率50Hz,占空比30%。用交流阻抗分析膜层的耐腐蚀性能,结果表明:最佳工艺条件下所制备微弧氧化,膜层电阻比镁合金基体提高了2个数量级,耐蚀性有所增强。     

电镀锌三价铬彩色钝化膜封闭剂的制备

目的制备性能良好的封闭剂,以提高电镀锌三价铬彩色钝化膜的耐蚀性。方法以氟化钠、硅酸钠、OP为主要原料制备封闭剂。采用5%醋酸铅点滴法测定封闭处理后的电镀锌三价铬彩色钝化膜的耐蚀性能,探讨了封闭剂的配方,分析了封闭时间、烘干温度、烘干时间等工艺条件对耐蚀性的影响,并通过正交试验对封闭工艺进行了优化,确定了以氟化钠和硅酸钠为主盐的封闭剂的钝化处理工艺规范。结果试验得到的封闭剂组成为:氟化钠0.2 mol/L,硅酸钠0.05 mol/L,OP 1 m L/L。采用该封闭剂,在浸渍时间20min、烘干温度80℃的条件下,醋酸铅点滴实验最高达到近900 s。结论封闭后膜层呈彩虹色,色泽明亮,钝化膜耐蚀性提高。     

热浸镀锌层偏钒酸盐转化膜成膜工艺的研究

为了获得可提高热浸镀锌层耐蚀性能、对环境污染小的转化膜工艺,采用无毒偏钒酸盐对热浸镀锌层进行钝化,研究了转化液组成、pH值、钝化处理温度及时间对钝化成膜及膜层耐蚀性的影响,确定了最佳工艺:NaVO35 g/L,pH值为1.3,处理温度为室温(25～30℃),处理时间10～30 min。通过中性盐雾(NSS)试验、附着力测试和电化学极化测试考察膜层的性能,结果表明,采用该工艺可获得耐蚀性明显高于纯锌层的优良转化膜,且其附着力好,结合牢固。     

镁合金表面SiO2-ZrO2溶胶凝胶膜的耐蚀性

采用溶胶-凝胶法在AZ91D镁合金表面制备SiO2-ZrO2复合溶胶凝胶膜.研究膜层制备工艺中的干燥、固化过程对膜层耐腐蚀性能的影响,从而确定了SiO2-ZrO2复合溶胶凝胶膜在镁合金表面的最佳沉积工艺.通过全浸腐蚀试验和电化学测试方法评价了膜层的耐腐蚀性能.试验确定最佳沉积工艺参数:干燥温度为80℃、干燥时间为9 h、固化温度为250℃、固化时间为1 h.在优化工艺条件下制备的溶胶凝胶膜层对镁合金基体有一定的防护作用,提高了镁合金的耐蚀性.     

基于热压工艺的涂镀板材性能分析

通过配制以稀土盐与镀锌板常用的有机缓蚀剂BTA,应用于锌的无铬钝化处理.分析了热压温度与时间对热锌板镀层钝化防腐学性能的影响.试验结果表明,随热压时间的延长,热锌板镀层钝化防腐学性能相应地提高,适宜的热压工艺条件为30 s/mm板厚的热压时间,70℃的热压温度.     

The mechanism of accelerated corrosion of copper-nickel alloys in sulphide-polluted seawater

Copper-nickel alloys are reported to suffer accelerated corrosion in sulphide-polluted seawater. In the present study, the corrosion rates of 90 : 10 Cu : Ni alloy tube specimens and the characteristics of the surface corrosion products were determined for several environmental exposure histories. Some specimens were exposed only to de-aerated, sulphide-polluted seawater, some were exposed only to aerated, unpolluted seawater, and others were exposed first to polluted then to unpolluted seawater. In addition, preliminary experiments were performed to determine the effect of pH (7.0–8.2) on the corrosion rates of both 90 : 10 Cu : Ni and 70 : 30 Cu : Ni alloys in sulphide-polluted de-aerated seawater. The results support a previous prediction that the presence of dissolved sulphide in seawater does not lead immediately to accelerated corrosion but rather that the porous cuprous sulphide corrosion product formed in the polluted water interferes with the normal growth of the protective oxide film on subsequent exposure to unpolluted seawater. This interference with the oxide growth allows the initially high corrosion rate in aerated seawater to be maintained for an abnormally long period.     

受BTA保护的白铜在模拟工业大气环境中的腐蚀行为

以涂盐沉积的方式进行室内加速实验,通过SEM/EDS、XRD和电化学测试等分析技术,研究受苯并三氮唑(BTA)保护的白铜在模拟工业大气环境中的腐蚀行为。结果表明,腐蚀初期受BTA保护的白铜表面存在棱状的盐结晶,说明腐蚀介质无法完全渗入基体。随着腐蚀时间延长,其对应的腐蚀电流密度呈现先减小后增大的趋势,其原因在于表面除了BTA化学转化膜还存在因腐蚀而产生的氧化膜,2者的共同作用延缓了腐蚀的进行,而当局部的BTA膜层因不断消耗出现破损,腐蚀区域则会从此处开始扩展,腐蚀电流密度也会随之增加。对比BTA处理前后的白铜,虽然最终的腐蚀产物主要成分均为ZnSO₄·6H₂O和Cu₄(SO₄)(OH)₆,呈现为疏松多孔状,但从截面形貌和动力学曲线分析,受BTA处理后的白铜腐蚀程度更轻微。     

Surface characterization and corrosion behavior of 70/30 Cu-Ni alloy in pristine and sulfide-containing simulated seawater

The corrosion behavior of the 70/30 Cu-Ni alloy in stagnant, aerated pristine and sulfide-containing simulated seawater as a function of exposure time was investigated with polarization curve measurement and electrochemical impedance spectroscopy (EIS). It was demonstrated that the compact protective oxide film formed on the 70/30 Cu-Ni alloy resulted in the decrease of corrosion rate in aerated pristine seawater; while the corrosion rate of 70/30 Cu-Ni alloy in aerated sulfide-containing seawater increased dramatically due to the catalysis of the sulfide ions or sulfide scale for both the cathodic and anodic reactions. The impedance spectra and the corresponding equivalent circuits confirmed that a duplex layer of a surface film was formed on the 70/30 Cu-Ni alloy in aerated pristine seawater after a period of time and that the inner layer was responsible for the good resistance of the alloy; while only a porous and non-protective corrosion product layer formed on the 70/30 Cu-Ni alloy in aerated sulfide-containing seawater, which made small values of charge transfer resistance (R_ct) to last for a abnormally long time by interfering with the growth of the protective oxide film. The composition of the surface film on the alloy in pristine and sulfide-containing seawater for different exposure times were investigated thoroughly by XPS. It was found that the duplex corrosion product layer formed on the alloy in pristine seawater was composed of an inner Cu₂O and an outer CuO layer. The porous and non-protective corrosion product layer formed on the alloy in aerated sulfide-containing seawater was a mixture of CuCl, Cu₂S, NiS, Cu₂O and NiO with trace amounts of CuO and Ni(OH)₂ and that the most significant component was Cu₂S. In addition, SEM was used to analyze the topography of the 70/30 Cu-Ni alloy in both solutions after different exposure times.     

Cu—Zn—Al形状记忆合金的缝隙腐蚀

采有利民化学方法研究了Cu-Zn-Al形状记忆合金及其BTA钝化处理试样在Hank′s人工体液中的缝隙腐蚀行为。结果表明：在人工体液中,Cu-Zn-Al形状记忆合金的耐缝隙腐蚀性能优于未进行热处理的Cu-Zn-Al合金,其作用机理是单相马氏体组织改善了合金的电化学行为,抑制了活性溶解,缝隙腐蚀的发生是由于形成了金属离子浓差电池。经BTA钝化后,Cu-Zn-Al形状记忆合金的耐缝隙腐蚀性能得到改善。     

铜镍合金在添加不同缓蚀剂的55%LiBr溶液中的腐蚀行为

采用电化学阻抗技术研究了LiOH、Na_2MoO_4和BTA对铜镍合金在55%LiBr溶液中的腐蚀行为的影响。结果表明,单独添加LiOH和BTA都能显著减缓铜镍合金在LiBr溶液中的腐蚀,而Na_2MoO_4含量较低时可能会加速腐蚀。三种缓蚀剂复配使用,对铜镍合金在55%LiBr溶液中的腐蚀具有更好的缓蚀效果,复配后具有协同效应。试验表明,复合添加0.10 mol/L LiOH、150 mg/L Na_2MoO_4和150mg/L BTA时,对铜镍合金在55%LiBr溶液中的腐蚀具有最优的缓蚀效率。     

温度对B30铜镍合金在海水中电化学行为的影响

采用线性极化、动电位极化、交流阻抗、循环阳极极化等测试方法,研究了温度变化对B30铜镍合金在海水中电化学行为的影响。结果表明:随着温度的升高,B30铜镍合金在海水中的腐蚀电流密度增大,生成的表面膜稳定性下降,点蚀倾向加重。     

铝及铝合金无铬钝化研究进展

铝合金可加工成各种板材、型材、铝铸件,为了减少其在工业环境中的腐蚀损失,需进行钝化处理.钝化常作为涂层的预处理步骤,钝化膜能增强铝合金表面与有机涂层的结合力,进一步提高涂层对基体的防护能力.目前无铬钝化主要是钼酸盐钝化、稀土盐钝化、锆/钛盐钝化及有机物钝化,因此对这几种主要化学钝化法的研究进程及现状进行了综述.钼酸盐复配其他盐协同缓蚀,能够获得更强的耐腐蚀性能.稀土盐中加入强氧化剂和成膜促进剂,可以简化处理工艺,降低腐蚀电流.锆、钛盐中加入有机物形成复合膜,能够改善单一膜层的耐腐蚀性能,提高与基体的结合力.硅烷在铝合金表面形成交联结构,从而表现出良好的封闭效果.在硅烷中加入纳米粒子可以获得更好的膜层表面形貌,加入稀土及其氧化物可提高耐腐蚀性能.硅烷两步法成膜过程中,成膜次序不同能够获得不同的膜层物理性能和耐蚀效果.最后,对未来无铬钝化工艺的研究方向进行了展望.     

Seawater corrosion of 70Cu‐30Ni alloy of incomplete recrystallization of intermittent and full immersion

The corrosion of 70Cu‐30Ni alloy of incomplete recrystallization was investigated by electrochemical technique, intermittent and full immersion in natural seawater, SEM and AES. Exposed to seawater for a short time, 70Cu‐30Ni alloy formed uniform and compact corrosion product films, which were rich in nickel, oxygen and seawater species for intermittent immersion; while the alloy fully immersed displayed loose and thick films, which were of denickelification and intergranular corrosion occurred to the underlying substrate. It was found that some regular crystals situated at the intersection of boundaries or the outer layer of the film and the crystals are ascribed to the reduction of cuprous ions to compensate the deficiency of oxygen for the cathodic process. Intergranular corrosion was observed in the underlying substrate for intermittent immersion after a long‐term exposure. Intermittent immersion can, to some degree, slow down the corrosion but not prevent the alloy of incomplete recrystallization from intergranular corrosion. Consequently, the corrosion mechanism of 70Cu‐30Ni alloy is proposed to be determined by its microstructure, independent of exposure conditions.     

Adsorbed corrosion inhibitors studied by electron spectroscopy: Benzotriazole on copper and copper alloys

Surface films formed by adsorption of benzotriazole (BTA), on copper and copper alloys have been studied by X-ray photo-electron spectroscopy (XPS). It is found that on both copper and copper-nickel alloys, benzotriazole forms a Cu(I)BTA surface complex. For the copper-nickel alloys the time taken to form the Cu(I)BTA film is dependent on the alloy composition. The Cu(I)BTA films were found to oxidize rapidly to a Cu(II) species on removal from the liquid phase. Surface films formed by BTA on 70 Cu : 30 Zn alloy were found to contain both copper and zinc, the copper again being in the Cu(I) state.A study of the adsorption of BTA on cathodically reduced copper surfaces strongly supports previous suggestions that the presence of Cu₃O facilitates formation of the surface film.