铝及铝合金黑色氧化膜的生成方法

专利申请范围 1.形成阳极氧化膜之后,使其氧化膜活性化或变化氧化膜结构,可以迅速地进行电解着色;在含有金属盐的电解着色液中再次进行阳极氧化处理,可均匀地着色;再者,在同一液体中进行交流、负的直流或脉冲通电,可以迅速而且均匀地生成黑色氧化膜。以上是这种铝及铝合金黑色氧化膜生成方法的特点。     

钢基电镀铝层阳极氧化处理后的组织结构和性能

用扫描电镜（SEM）和X射线衍射分析（XRD）测定了Q235钢上电镀铝层在硫酸溶液中不同时间阳极氧化处理后的组织结构和表面形貌，并对其硬度和耐蚀性能进行了测试。结果表明：电镀铝层经不同时间阳极氧化处理后，表面由非晶态Al2O3相和Al相组成，其上存在有纳米级的孔洞。随着氧化时间的延长，非晶态Al2O3相增多，Al相减少，氧化膜厚度增加，表面孔洞尺寸增大；氧化膜的硬度呈现先增加后降低，最后趋于稳定，且都显著高于电镀铝层的硬度。并且电镀铝层经阳极氧化处理后，在3．5％NaCl溶液中的电化学耐蚀性能大幅度增加，但随着阳极氧化处理时间的延长，电镀铝层的耐蚀性能降低。     

在铝或铝合金上形成彩色条纹的方法

铝件的早期电解着色法是在铝的阳极氧化膜上均匀地着色(单色),一般是把预先阳极氧化后的铝,在含有金属盐或酸的溶液中,用直流(阴极电解),交流或交直重叠电流或具有同等效果的各种波形电流进行电解,从而得到某种均匀色彩的.本发明方法是把予先经过阳极氧化处理后的铝件,放在不以着色为目的的酸或由酸性金属盐组成的电解液中,在此电解液的下部,有一种比重较大,且与该电解液互不溶解     

钢基电镀铝层阳极氧化处理后的组织结构和性能

用扫描电镜(SEM)和X射线衍射分析(XRD)测定了Q235钢上电镀铝层在硫酸溶液中不同时间阳极氧化处理后的组织结构和表面形貌,并对其硬度和耐蚀性能进行了测试.结果表明:电镀铝层经不同时问阳极氧化处理后,表面由非品态Al2O3相和Al相组成,其上存在有纳米级的孔洞.随着氧化时间的延长,非晶态Al2O3相增多,Al相减少,氧化膜厚度增加,表面孔洞尺寸增大;氧化膜的硬度呈现先增加后降低,最后趋于稳定,且都显著高于电镀铝层的硬度.并且电镀铝层经阳极氧化处理后,在3.5%NaCl溶液中的电化学耐蚀性能大幅度增加,但随着阳极氧化处理时间的延长,电镀铝层的耐蚀性能降低.     

铝制零件表面着色新技术

日本专家研究成功一种铝制零件表面着色新技术,该项技术只需使用一种金属盐,就能将铝的阳极氧化膜层着上蓝、绿、红等任意颜色。其着色工艺过程是:首先将铝制零件在磷酸和硫酸的溶液中进行阳极氧化处理,然后在含有磷酸等的电解液中用低电流密度进行电解,最后再放入含有金属盐(可用铁、镍、钴、锡等任何     

温度对铝阳极氧化的影响

为了提高铝合金零件的防腐蚀能力,增加零件耐磨性,铝及铝合金制品通常需要进行阳极氧化处理或硬质阳极氧化处理。铝的阳极氧化是以铝或铝合金作阳极,以铅板、不锈钢板作阴极,在硫酸、草酸、铬酸等水溶液中电解,使其表面生成氧化膜层。其中,硫酸阳极处理应用最为广泛。铝和铝合金硫酸阳极氧化膜层有较强的吸附能力,易进行封孔或着色处理,以提高其抗蚀性和美观性。阳极氧化膜层厚一般5—25um,铝合金硫酸阳极氧化工艺操作简单,电解液稳定,成本也不高,是成熟的工艺方法。     

铝表面高压阳极氧化膜层结构分析

采用X射线衍射（XRD）、扫描电镜（SEM）和X射线光电子能谱（XPS）综合分析了铝在磷酸和钨酸钠体系中形成的高压阳极氧化膜的成分、形貌和结构。XPS结果表明,氧化膜的主要组成元素为O和Al,同时夹杂有少量的P和W。SEM分析发现,氧化膜呈网状结构,孔隙率约为10个／μm^2,孔径大小为0．15－0．20μm。氧化膜大致可以分为紧密层和疏松层两层。紧密层、疏松层、基体三者之间相互交错,紧密相连。SEM显示,紧密层和疏松层中均存在大量的龟裂纹。XRD分析表明,氧化膜呈现非晶态结构,以铝的氧化物主要组成成份,同时杂有少量的磷酸盐或钨酸盐。     

铝合金在HEDP电解液中的阳极氧化行为及膜层结构EI北大核心CSCD

选用羟基乙叉二膦酸(HEDP)为电解液对1060铝合金进行阳极氧化,分析了其在恒压氧化过程中的电流变化特征;借助FESEM、EDS、XRD等分析了氧化膜的微观结构、化学组成及其演变过程,探讨HEDP阳极氧化膜的生长机制;通过动电位极化曲线评价HEDP阳极氧化处理铝合金的耐蚀性。结果表明:HEDP体系中铝合金阳极氧化膜的形成是一个电化学成长与化学溶解的动态调整过程。HEDP阳极氧化膜与硫酸阳极氧化膜类似,也呈双层结构;外层为蜂窝孔状结构,只是孔径略大;内层为壁垒型结构,但明显更厚;膜层主要由非晶态Al_(2)O_(3)组成,同时多孔层中含有一定量的水合Al_(2)O_(3)。随着氧化时间的延长,孔径和孔隙率会不断增大;氧化30 min时,膜层厚度为4~5μm,表面孔径为110~120 nm,阻挡层厚度约154 nm。HEDP阳极氧化膜大幅提升了1060铝合金的耐蚀性,且膜层厚度相当时,其耐蚀性优于铬酸阳极氧化膜。     

铝及铝合金在亚铁盐溶液中电解着色

铝及铝合金在含有2g/L的SB添加剂的150~180g/LH2SO4溶液中进行阳极氧化,得到多孔且无阻挡层的氧化铝膜。该膜在含有FesO4的溶液中进行交流电解着色,得到系列棕色膜。关键词##4铝;;阳极氧化;;电解着色;;硫酸亚铁;;棕色膜     

稀土盐封孔Al 6061/SiC_p复合材料阳极氧化膜性能研究

研究了Al6061/SiCp复合材料阳极氧化稀土盐封孔工艺。利用电化学方法评价了氧化膜的耐腐蚀性能,稀土盐封孔氧化膜的耐蚀性与铬酸盐封闭阳极氧化膜具有可比性。利用X射线衍射分析(XRD)了氧化膜的结构,结果表明氧化膜为非晶态。X射线光电子能谱(XPS)分析证明氧化膜表面的主要成分是铈的氢氧化物。     

A study of conversion coating development on aluminium in chromate/fluoride solutions using secondary ion mass spectrometry

A Cameca Ion Analyzer has been used to examine aluminium surfaces, covered by 73 nm thick barrier type anodic films, after natural immersion for 1–15 min in a chromate/fluoride conversion coating solution at 293 K. The conversion coating produced is essentially amorphous chromium-containing material, probably largely hydrated chromic oxide, but contains a cellular-type structure with aluminium and fluoride, probably as complex oxyfluoride, concentrated in the inter-cellular regions. The major role of the F^? ion is to remove the initial oxide film, maintain the surface active and permit nucleation and lateral growth of the conversion coating over it. The F^? ion is more aggressive towards anodic and other alumina than CrO₄^2? and PO₄^3? ions, without appearing to enter the anodic film material per se, but is also more aggressive towards the aluminium substrate than C1^? ion, acting initially at flaws and undermining the film.     

Fundamental and practical evaluations of PEO coatings of titanium

Abstract

Plasma electrolytic oxidation (PEO) enables fabrication of high performance ceramic surfaces on the light metals, with thickness, topography, composition and structure controllable by the process parameters. The growth of anodic coatings on titanium has been investigated at a fundamental level, and understanding of coating growth has been enhanced. Discrete thickening at sites of dielectric breakdown, local growth at the metal/oxide interface and destruction of earlier formed oxide were shown, offering a new perspective on coating processes, including those aspects affecting coating efficiency. Routes to tailored coating compositions for enhanced biocompatibility have been developed, and carried through to in vitro evaluation. Fabrication of amorphous oxide, which is beneficial to biocompatibility, was achieved through anodising at controlled current densities and with use of complexing agents. Corrosion tests of the coatings revealed low titanium release into physiological solution, which is important to avoid adverse tissue reaction. In vitro tests confirmed good attachment of human osteoblast cells to the fabricated titanium oxide coatings.     

The effect of oxide coatings on fatigue properties of 7475-T6 aluminium alloy

The effect of hard anodic oxide and plasma electrolytic oxide coatings on the fatigue strength of 7475-T6 aluminium alloy has been investigated. The coated aluminium alloy was tested using constant load uniaxial tensile fatigue machine. Hard anodising led to an appreciable reduction in the fatigue strength of 7475-T6 alloy of about 75% for a 60 μm thick coating. Further, plasma electrolytic oxidation resulted in reduction of the fatigue strength of about 58% for a 65 μm thick oxide coating. The decrease in fatigue strength of the hard anodic oxide coatings was associated with the stress concentration at the microcracks in the coating. The better fatigue performance of the PEO coatings was attributed to the development of the compressive residual internal stress within the coatings. The reduction in the fatigue strength of the PEO coatings as compared to the uncoated material was associated with the development of the tensile residual internal stress within the substrate. This may cause an early crack initiation in the substrate adjacent to the coating.     

铝阳极氧化膜冷封孔机理研究——Ⅰ.冷封孔氧化膜的组成结构

应用X-射线衍射、红外光谱、热重和差热分析对铝在硫酸中阳极氧化后经BY02封孔剂冷封孔处理的氧化膜组成结构进行了研究,结果表明:铝的阳极氧化膜主要由无定形氧化铝组成,膜中含有SO_4~(2-);在冷封孔反应过程中形成了AlOOH、Ni(OH)_2和AlF_3等产物。文中还讨论了冷封孔反应机理。     

Two-step plasma electrolytic oxidation of Ti-15V-3Al-3Cr-3Sn for wear-resistant and adhesive coating

Ti-15V-3Al-3Cr-3Sn (Ti-15-3) is one of the important practical titanium alloys with high cold deformability and high mechanical strength, but its wear resistance is poor. This paper reports the formation of wear-resistant and adhesive ceramic coatings on Ti-15-3 by two-step plasma electrolytic oxidation (PEO). The PEO of Ti-15-3 has been carried out first in alkaline aluminate electrolyte to form a wear-resistant oxide layer and then in acid electrolyte containing both phosphoric acid and sulfuric acid to improve adhesion of the coating. The coating formed in the alkaline aluminate electrolyte is more than 10 μm thick, and highly crystalline. The main phase is Al₂TiO₅. This coating shows high wear resistance, but is not adherent to substrate due to the development of a number of voids and pores in the oxide layer close to the substrate. A new oxide layer with amorphous structure is formed next to the substrate in the subsequent PEO in the acid electrolyte, during which the voids are filled with a new oxide formed in the acid electrolyte, reducing the porosity. As a consequence, the adhesion of the coating is markedly improved without deteriorating the high wear resistance.     

Untersuchungen zur Morphologie von Aluminiumhydroxiden und anodischen Aluminiumoxiden mit dem Rasterelektronenmikroskop

Investigations on the morphology of aluminium hydroxides and anodic aluminium oxide films using scanning electron microscope Hydroxide films of spongy structure are originated on aluminium surfaces if aluminium is trated with hot water for short periods. By increasing the reaction time the hydroxide layers start to become more compact until films are growing coherent showing a porous surface. If the reaction time exceeds 4 hours at a reaction temperature of 98°C crystalline scales appear on the top of the films. During the anodic oxydation of hydroxide coated aluminium in citric acid solutions, thin hydroxide films transform into barrier layer type oxides. If the anodization occurs in aggressive electrolytes the existing hydroxide dissolves and oxide layers with porous structure are obtained. Oxide layers produced by anodizing in hot citric acid solutions in the absence of a hydroxide film show a current density dependent morphology. At higher current densities barrier layer type oxides are growing. Using low current densities oxide layers with a character are predominating.     

Corrosion performance of anodic films containing polyaniline and TiO2 nanoparticles on AA3105 aluminium alloy

The corrosion protection afforded to an AA3105 aluminium alloy supporting an anodic film with incorporated polyaniline and TiO₂ nanoparticles has been examined. The films were synthesised by simultaneous anodizing and electropolymerisation of aniline in the presence of nanoparticles. The morphology and composition of the films were probed by TEM, SEM, rf-GDOES and XPS. The resultant coatings comprised a thin porous anodic film of 2-3 µm thickness, with an outer hybrid polyaniline/TiO₂ layer of several tens nanometres thickness, with the dimensions of TiO₂ nanoparticles being below 10 nm. Electrochemical impedance spectroscopy analysis and salt spray testing revealed that TiO₂ containing films provide improved corrosion protection to the AA3105 aluminium alloy compared with the film without nanoparticles. The improved protection provided by the coatings containing TiO₂ nanoparticles is attributed to the TiO₂ particle-rich thin film layer formed on the outer part of the coating that acts as a blocking barrier layer for the anodic porous aluminium oxide film.     

激光熔覆Ni_(59.35)Nb_(34.45)Sn_(6.2)非晶复合涂层组织与性能研究

为了达到研究预置激光熔覆可以在45钢上制备Ni基非晶合金涂层的目的,采用非晶形成能力三判据原则及非晶成分团簇线定律法则,选择了采用常规非晶合金制备方法中具有极大玻璃形成能力(GAT)的Ni_(59.35)Nb_(34.45)Sn_(6.2)合金粉末,在保护气氛下,制备非晶涂层,并对不同输出功率下得到的涂层进行微观组织和结构表征及性能测试.结果表明:激光熔覆Ni_(59.35)Nb_(34.45)Sn_(6.2)涂层中除含有非晶相外还含有Nb_3Sn、Nb_2Ni、Ni_3Sn_2及Ni和Sn的氧化物相.当激光功率为3300 W时,熔覆层表层显微硬度值最大为1638.1 HK;涂层由于非晶相的存在耐蚀性有明显提高,在该功率下致盹电流密度和维钝电流密度都达到最小,分别为1.3537 mA/cm~2和0.2652 mA/cm~2.     

Porous anodic oxides on titanium and on a Ti-W alloy

The growth of a nanoporous anodic oxide on titanium and a Ti-20 at.% W alloy, both deposited by magnetron sputtering, in a glycerol/phosphate electrolyte at 453 K is reported. The oxide formed on titanium is a mixture of amorphous titania and anatase. However, that on the alloy is amorphous only and forms at increased efficiency, about 27%. The amorphous structure is considered to be stabilized by incorporated units of WO₃, which are distributed uniformly throughout the anodic film. The growth of the porous oxides is suggested to be associated with loss of film species at the film/electrolyte interface at the base of pores, with new oxide forming exclusively at the metal/film interface by inward migration of O²⁻ ions.     

Effect of surface condition on the oxidation behaviour of MCrAlY coatings

Coatings of the MCrAlY type (M = Ni, Co) are commonly used as overlay coatings and as bond coats (BC's) for ceramic thermal barrier coatings (TBC's) in industrial gas turbines. During high temperature service the MCrAlY coatings form aluminium based surface oxide scales. The technologically most relevant properties of the oxide scales, growth rate and adherence do not only depend on the exact MCrAlY composition but also on the surface condition after coating manufacturing. Depending on the coating manufacturing process, the MCrAlY surfaces may substantially differ in roughness. In addition the coatings may be subjected to surface treatments (e.g. shot peening, grinding or smoothening prior to deposition of TBC). In the present work the effect of the surface roughness commonly prevailing in the case of vacuum plasma sprayed MCrAlY coatings on the morphology and composition of the alumina scales formed during high-temperature oxidation was studied. For this purpose free standing coatings with rough and polished surfaces were oxidised in the temperature range from 800 to 1100 °C with exposure times up to 1000 h. The surface scale composition and morphology were analysed by optical metallography and SEM. Fluorescence spectroscopy was used for stress measurements in the oxide scales. It has been found that the oxide scales formed on rough surfaces of MCrAlY coatings have an intrinsically different morphology and growth rate compared to those formed on the flat ground surfaces.