连铸结晶器铜板表面处理关键技术的研究与应用

结晶器涂镀前处理、表面涂镀层和涂层结构设计,是结晶器表面处理的关键技术.采用一步脱脂、刻蚀前处理工艺与采用传统前处理工艺相比,工件表面不仅粗糙度更高,而且更均匀.考察了几种结晶器表面涂镀层的热稳定性和耐磨损性能,喷涂涂层和Co-Ni镀层具有很好的热稳定性能和耐磨损性能,并具有良好的使用实绩.表面涂层的结构设计,包括涂层的厚度及厚度分布、多种涂层的组合使用等,都会显著影响结晶器的使用寿命.     

霉菌对A04-60氨基烘干磁漆的侵蚀作用研究

通过采用霉菌实验、扫描电子显微镜(SEM)、原子力显微镜(AFM)、电化学阻抗谱(EIS)等方法与手段研究了霉菌侵蚀对A04-60氨基漆表面微观形貌、防护性能等的影响,鉴定了侵蚀菌种。结果表明,导致A04-60氨基漆变质的主要因素是黑曲霉,霉菌生长提高了涂层表面粗糙度,表面缺陷不断扩大和深入,使得涂层的阻抗值和防护性能下降。     

高通量测序分析南美洲圭亚那输变电周围金属锈蚀材料中细菌多样性的研究

作为圭亚那输变电项目的EPC总承包商,中机公司非常重视项目所供设备和材料的材质、性能、使用寿命等方面的问题。此外,南美洲圭亚那属于热带雨林气候,高温多湿有利于金属材料表面微生物的生长,进而导致金属锈蚀。目前,对该国金属锈蚀材料中细菌物种多样性及其群落结构特征尚不明确。因此,本研究对南美洲圭亚那输变电工程周围区域金属锈蚀材料中的细菌群落进行16S rRNA基因(V3～V5区)高通量测序(Illumina Miseq),分析了6份金属锈蚀材料中细菌物种多样性及其群落组成,结果共获得139 626条有效序列,聚类为522个可操作分类单元(Operational Taxonomic Unit,OTU),获得分类地位明确的细菌种类为13门、24纲、64目、166属,以放优势门为放线菌门(Actinobacteria)、变形菌门(Proteobacteria)为主,优势属为囊胚菌属(Blastocatella)、红色杆菌属(Rubrobacter)、螺状菌属(Spirosoma)、甲基杆菌属(Methylobacterium)、放线孢菌属(Actinomycetospora)、鞘氨醇单胞菌属(Sphingomonas)等,而不同锈蚀样品之间在群落组成方面也存在一定差异。上述结果揭示了圭亚那输变电工程周围区域金属锈蚀材料的群落结构及物种多样,为后续圭亚那地区的输电线路和变电站的设备和材料供货商在金属材料防锈蚀的研发工作方面提供了理论依据。     

烧结型NdFeB永磁体的防腐蚀研究进展

近年来对烧结型NdFeB永磁材料表面防护层的研究不断取得进步.概括了NdFeB的成分和相结构,系统地介绍了NdFeB永磁体防腐蚀方法,主要包括改善磁体本身性能和对磁体进行表面处理2种方法.综合分析可知:目前的表面防护措施主要存在2点不足之处,即涂层工艺操作复杂,成本高;涂层的耐腐蚀性、厚度、均匀性及结合力仍达不到预期要求.最后,针对不足,我们提出可从改善前处理工艺和开发新的涂镀工艺入手,从而获得满足生产要求的镀层性能.     

热带雨林环境中典型霉菌对PCB-HASL腐蚀行为的影响

目的探究热带雨林环境中典型霉菌作用下PCB-HASL的腐蚀机制。方法将PCB-HASL试样灭菌后放入机箱,置于西双版纳户外进行2年的暴露试验,经不同周期取回,分析观察试样表面腐蚀情况。将筛选出的典型霉菌孢子液喷洒在无菌试样上,置于湿热环境中,通过激光共聚焦显微镜(3D LSCM)、扫描电子显微镜(SEM)和能谱仪(EDS)分析试样表面形貌和成分,并观察霉菌的生长情况,使用电化学工作站及扫描开尔文探针(SKP)对PCB-HASL表面不同周期霉菌作用下的腐蚀电位进行分析。结果随着户外暴露周期的增加,PCB-HASL表面腐蚀面积逐渐增加,表面伏打电位先上升后下降。EDS能谱分析结果表明,腐蚀产物中主要含Sn 58.88%,O 30.93%,腐蚀产物主要为Sn的氧化物。木贼镰孢菌(Fusarium equiseti)和光轮层炭壳菌(Daldinia eschscholtzii)覆盖区域腐蚀程度严重,腐皮镰刀菌(Fusarium solani)菌丝生长旺盛,中期腐蚀电位明显降低,由-0.3 V降至-0.52 V。结论西双版纳热带雨林环境中对PCB-HASL腐蚀作用显著的典型霉菌为Fusarium equiseti、Daldinia eschscholtzii和Fusarium solani,在湿热环境下会造成PCB-HASL的腐蚀,其腐蚀机制主要为薄液膜下的电化学腐蚀。     

燃油箱用无铅表面处理钢板材料的发展

镀铅锡合金钢板是传统的汽车燃油箱钢板材料,但由于人们环保意识的增强,燃油箱无铅化已是大势所趋.发达国家的许多钢铁厂开发了各种无铅且耐蚀性更好的汽车燃油箱用表面处理钢板材料,包括无铅镀层钢板和预涂层钢板两大类.热浸镀Al钢板、热浸镀Zn-Sn钢板、电镀Zn-Ni钢板、热镀Zn闪镀Ni双层镀钢板等无铅镀层钢板和预涂层GA钢板、预涂层电镀Zn-Ni钢板等预涂层钢板都已在汽车上应用.具有优良耐蚀性、成形性和焊接性的无Pb、无Cr(VI)预涂层钢板已成为汽车燃油箱钢板发展的方向.     

结晶器基材HVOF喷涂梯度功能涂层组织结构与结合强度

以HVOF梯度功能涂层在结晶器的应用作为研究背景,对CrZrCu表面超音速火焰喷涂CoNiCrAlY＋CoCrMoSi梯度涂层与Ni-Co电镀层进行了对比分析,通过SEM,EDS,XRD及X射线应力仪等手段分析了涂/镀层的微观组织结构与应力状态,采用拉伸法测试了结合强度.结果表明,涂层与基体之间的结合比镀层较为紧密;梯...     

电磁屏蔽涂镀层的研究现状及进展

主要讨论了电磁屏蔽（EMS）的基本原理和相关的电磁屏蔽知识，简述了国内外近年来重点开发的各种电磁屏蔽化学涂层、镀层，总结了当前电磁屏蔽涂镀层的研究现状和进展，为解决敏感设备的电磁屏蔽（EMS）问题和进一步研究开发电磁屏蔽涂镀层材料提供参考。     

SiC涂层对泡沫炭高温抗氧化性能的影响

采用包埋法在中间相沥青基泡沫炭表面生成了一层致密的高温抗氧化碳化硅涂层,研究了SiC涂层对泡沫炭高温抗氧化性能的影响.通过热重分析仪(TG)对有、无SiC涂层的泡沫炭的抗氧化性能变化进行了分析,采用扫描电子显微镜(SEM)分析了SiC涂层的结构和形貌特征变化,同时在1 200℃空气气氛中对SiC涂层的抗氧化性能进行了测试.结果表明:SiC涂层使泡沫炭的抗氧化性能有了显著的提高,并且随着SiC涂层厚度的增加,泡沫炭的抗氧化性能也随之增强.     

钙镁橄榄石等离子涂层及其生物活性研究

采用大气等离子喷涂技术,在Ti-6A1-4V基体上制备了钙镁橄榄石涂层,研究了热处理对涂层组织结构及结合强度的影响,并对此材料作了体外模拟液浸泡及细胞共培养试验.结果表明,热处理前涂层的结晶度较低,热处理(400～900℃)能有效降低涂层的孔隙率、提高涂层的结合强度.在700℃下热处理后,涂层具有最低的孔隙率,结晶度较高,组织比较均匀,膨胀系数与基体材料接近,因而具有最高的结合强度(达到37 MPa)和很好的稳定性.此涂层在模拟体液中浸泡7 d后表面明显有磷灰石出现.成骨细胞在材料表面的贴壁试验说明,细胞在材料表面生长旺盛,表明该涂层具有很好的生物相容性.     

Ra 及 Rpc 对无铬耐指纹热镀锌板表面性能的影响

目的研究热镀锌板表面平均粗糙度Ra和峰值数Rpc对无铬耐指纹热镀锌板表面耐指纹性、耐腐蚀性和涂装性的影响。方法将Ra=0.6~1.1μm和Rpc=55~100的热镀锌板制成耐指纹板,采用X射线光电子能谱仪分析其组成,采用分光光度仪分析其耐指纹性,采用硫酸铜混合溶液滴定和盐雾试验方法检测其耐腐蚀性,采用涂漆和冲击实验检测其涂装性。结果耐指纹膜和锌层表面形成Si—O—Zn金属键,耐指纹膜除了物理结合,还通过化学键合的方式与锌层表面结合。在充分交联固化和化学键合的情况下,无铬耐指纹热镀锌板耐指纹性不受热镀锌板Ra和Rpc的影响;热镀锌板Ra值越低,耐腐蚀性越好;耐指纹膜单位质量为1.1 g/m2,Ra≤1.1μm时,耐指纹板72 h盐雾试验白锈面积不大于5%;热镀锌板Rpc值越高,无铬耐指纹热镀锌板涂装性越好,Rpc≥80时,耐指纹热镀锌板涂漆冲压后,漆膜完好。结论 Ra和Rpc对热镀锌板耐指纹性影响不大,对耐磨蚀性和涂装性影响显著。     

电流密度对ZK60镁合金表面超疏水涂层的制备及耐腐蚀性的影响

为了提高镁合金的耐腐蚀性能,基于层状双氢氧化物（LDHs）膜在ZK60镁合金表面制备了超疏水（SH）涂层。涂层制备过程中引入电场辅助,研究了工作电流密度对涂层性能的影响。结果表明,工作电流密度显著影响LDHs膜的微观结构,这对SH涂层的疏水性具有重要影响。当工作电流密度为25 mA/cm²时,SH涂层表面呈现均匀的微纳米结构,并表现出超疏水性。超疏水涂层的腐蚀电流密度（I_corr=9×10^-7 A·cm^-2）比ZK60基体的腐蚀电流密度（I_corr=3×10^-5 A·cm^-2）低了2个数量级,表现出优异的耐腐蚀性。     

Improving corrosion properties of high-velocity oxy-fuel sprayed inconel 625 by using a high-power continuous wave neodymium-doped yttrium aluminum garnet laser

Thermal spray processes are widely used to protect materials and components against wear, corrosion and oxidation. Despite the use of the latest developments of thermal spraying, such as high-velocity oxy-fuel (HVOF) and plasma spraying, these coatings may in certain service conditions show inadequate performance,e.g., due to insufficient bond strength and/or mechanical properties and corrosion resistance inferior to those of corresponding bulk materials. The main cause for a low bond strength in thermalsprayed coatings is the low process temperature, which results only in mechanical bonding. Mechanical and corrosion properties typically inferior to wrought materials are caused by the chemical and structural inhomogeneity of the thermal-sprayed coating material. To overcome the drawbacks of sprayed structures and to markedly improve the coating properties, laser remelting of sprayed coatings was studied in the present work. The coating material was nickel-based superalloy Inconel 625, which contains chromium and molybdenum as the main alloying agents. The coating was prepared by HVOF spraying onto mild steel substrates. High-power continuous wave Nd:YAG laser equipped with large beam optics was used to remelt the HVOF sprayed coating using different levels of power and scanning speed. The coatings as-sprayed and after laser remelting were characterized by optical microscopy and scanning electron microscopy (SEM). Laser remelting resulted in homogenization of the sprayed structure. This strongly improved the performance of the laser-remelted coatings in adhesion, wet corrosion, and high-temperature oxidation testing. The properties of the laser-remelted coatings were compared directly with the properties of as-sprayed HVOF coatings and with plasma-transferred arc (PTA) overlay coatings and wrought Inconel 625 alloy.     

Improving corrosion resistance of aluminium metal matrix composites using cerium sealed electroless Ni–P coatings

Abstract

A conversion coating treatment using cerium salts was developed for the surface sealing of electroless nickel–phosphorus (Ni–P) coatings on carbon fibre reinforced aluminium (Cf/Al) composites. The corrosion resistances of uncoated and coated materials (i.e. the Ni–P coating, the Ce conversion coating and Ce sealed Ni–P coatings) were evaluated in 3·5 wt-%NaCl solution using potentiodynamic polarisation and electrochemical impedance spectroscopy. Ce sealed Ni–P coating showed the highest corrosion resistance and clearly improved the overall corrosion resistance of Cf/Al composites. Thus, the Ce sealed Ni–P coating had no obvious microcracks that were generally evident in the more conventional Ce conversion coatings. This is presumed to occur because the electroless nickel surface is relatively homogeneous, compared with the Cf/Al composite surface on which different local coating thicknesses would encourage increased microcrack formation. X-ray photoelectron spectroscopy analysis showed that the Ce conversion coating mainly contained both Ce³⁺ and Ce⁴⁺ species; however, Ce⁴⁺ species were the dominant oxidation state on Ce sealed Ni–P coatings.     

Characterisation and corrosion resistance of Zn–Mn coatings electrodeposited from acidic chloride bath

Zn–Mn alloy coatings were galvanostatically electrodeposited from an acidic chloride bath. Effects of deposition current density, pH and temperature on surface morphology, microstructure and corrosion resistance of Zn–Mn coatings were studied. The coatings deposited at 10, 50 and 100 mA cm^?2 had a single η-Zn phase structure. However, a dual phase structure of η-Zn and ?-Zn–Mn with higher Mn content was found for the coatings deposited at 200 mA cm^?2. The dual structure degraded the corrosion resistance of the coatings. The highest corrosion resistance was achieved for the Zn–Mn coating deposited at 100 mA cm^?2, pH 4·9 and 25°C. This coating contained 4·1 wt-%Mn and showed a unique surface morphology consisting of randomly arranged packs of very thin platelets, laid perpendicular to the surface and provided a high compactness deficient free structure.     

TiN, TiN gradient and Ti/TiN multi-layer protective coatings on Uranium

Single-layer TiN, gradient TiN and multi-layer Ti/TiN coating were deposited on silicon and uranium substrates by means of arc ion plating technique. The main phase in the single-layer TiN coating was TiN with a (111) preferred orientation. Ti and TiN were observed in the TiN gradient coating and Ti/TiN multi-layer coatings. The single-layer TiN coating has demonstrated the best wear resistance among the three coatings. Compared with the bare U substrate, the corrosion potential E_corr of the multi-layer Ti/TiN coatings is increased by 580 mV, and the corrosion current density I_corr is decreased at least by two orders of magnitude. The multi-layer Ti/TiN coatings possessed the highest corrosion resistance among the three coating in a 0.5 μg/g Cl⁻ solution.     

Effect of TiO2 nanoparticles on anticorrosion property in amorphous Ni-P-Cr composite coating in artificial seawater and microbial environment

To obtain the composite with a function of corrosion resistance in seawater and microbial environment, we apply low toxic electrolyte which contained Cr³⁺ instead of Cr⁶⁺ as a chromium source to produce Ni-P-Cr/TiO₂, Ni-P-Cr/ZrO₂ nanocomposite coatings, and Ni-P-Cr/TiO₂ microcomposite coating using direct current (DC) electrodeposits technique. The surface morphology, texture, and composition of the composite coatings are characterized by SEM, XRD, and EDX measurements, respectively. The corrosion behavior of the composite coatings is evaluated by polarization curves and electrochemical impedance spectroscopy (EIS). The results with more positive-shifting E_corr, lowest i_corr, and relatively high value of polarization resistance (R_p) proved that compared with other composite coatings, Ni-P-Cr/TiO₂ nanocomposite coating with its better passive film and unique antibacterial activity caused by TiO₂ nanoparticles incorporated, displayed excellent antibacterial and corrosion resistance property, consistent to the phenomenon that corrosion of this nanocomposite coating in SRB culture medium is not observed.     

Application of Plasma Enhanced Chemical Vapor Deposition for Fingerprint Resistance

SiOx and diamond-like carbon(DLC)coatings as the fingerprint resistance and corrosion resistance layers were deposited by capacitively coupled plasma(CCP)-enhanced chemical vapor deposition powered by radio frequency(RF-PECVD).In here hexamethyldisiloxane(HMDSO)as monomer for SiOx coating,C2H2 as the carbon source for DLC growth precursor,and Ar as the dilution gas were utilized.The important factors affected fingerprint resistance was explored in detail.Besides,the corrosion resistant test on coatings and substrates were then examined by the potentiodynamic polarization measurement and salt-spray corrosion test,respectively.The chemical structure and composition of SiOx and DLC films were analyzed by FTIR,and the relationship between them and anti-corrosion property was discussed.The results show that the DLC coating demonstrates a better anti-fingerprint behavior than that of coated SiOx,especially in acidic solution environment.     

The effect of calcination on the corrosion performance of TiO2 sol–gel coatings doped with benzotriazole on steel CK45

Sol–gel method under dip coating process and tetra‐n‐butyle orthotitanate as precursor were used to produce titanium oxide coating on steel CK45. The effect of calcination at 400 °C, after drying at 120 °C, on the morphology and corrosion performance of the coatings was investigated. Benzotriazole (BTA) as an inhibitor was doped on titanium oxide coatings to improve corrosion performance of the coatings as well as its self‐healing properties. The morphology and structure of the coatings were studied by X‐ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive X‐ray spectroscopy (EDS) techniques. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques were used to study the corrosion behavior of the coatings. The results revealed that after calcination the dominant crystalline phase was anatase. The results obtained from potentiodynamic polarization curves and electrochemical impedance spectra showed that the calcinated and doped with BTA coatings possessed higher corrosion resistance than non‐calcinated although doped with BTA coatings.     

高温防护涂层的熔盐热腐蚀研究进展

高温热腐蚀是热元件主要失效形式之一,Na₂SO₄和NaCl熔盐会加速高温下的热腐蚀,甚至导致灾难性事故发生。本文就Na₂SO₄和/或NaCl熔盐引起的热腐蚀进行了讨论,其中Na₂SO₄是主要的腐蚀反应物,详细介绍了2种典型的热腐蚀行为和性能特点。重点介绍了几种热腐蚀模型和机理,以及Na₂SO₄、NaCl、Na₂SO₄+NaCl熔盐的反应公式和腐蚀机理。根据目前的研究状况来看,制备防护涂层是缓解热腐蚀的最佳途径,总结了近年来MCrAlY涂层、NiAl涂层、热障涂层和新型涂层的发展情况,并探讨了进一步提高涂层耐腐蚀性能的方法。最后,展望了防护涂层的未来发展方向。