铝颜料表面改性防腐技术的研究与发展

结合国内外学者对铝颜料的改性手段和技术,概括了铝颜料表面改性中常用的多种无机材料和有机材料,介绍了铝颜料表面改性的主要方法,包括溶胶/凝胶法、原位聚合法、乳液聚合法、等离子聚合法和分散聚合法等,最后针对改性铝颜料的性能变化阐述了采用不同的改性材料和改性方法对铝颜料性能改善方面的影响,并指出了铝颜料表面防腐改性的未来研究趋势。     

铝锆偶联剂表面修饰稀土长余辉发光材料的研究

采用TL系列铝锆偶联剂对铝酸盐长余辉发光颜料(夜光粉)SrMgAl4O8:Eu2 、Dy3 进行表面改性.通过水解pH值、电导率、ATR-FTIR、XRF、SEM分别表征了改性前后试样的变化.结果表明:采用12%添加量的TL-1铝锆偶联剂在70 ℃下反应1.5 h,对长余辉发光颜料的改性效果最好,耐水性最佳;试样余辉衰减曲线表明,表面改性对其发光性能影响不大.     

硅烷偶联剂改性的纳米二氧化硅包覆铝颜料的制备及其耐碱性能

在醇/水体系中,采用溶胶/凝胶法制备了硅烷偶联剂改性的纳米二氧化硅包覆的铝颜料,并采用SEM、FTIR等分析方法对包覆效果进行表征,检测了包覆产物的耐碱性,并对过程机理进行了分析。结果表明,硅烷偶联剂改性的二氧化硅可以在铝颜料表面形成一层包覆层,且硅烷偶联剂的含量越高,包覆层中颗粒物的含量越少,而有机膜的含量越高。硅烷偶联剂改性二氧化硅包覆铝颜料在pH值为11的碱性水溶液中,经720 h后,析出的氢气量为未包覆产品的2.7%,表明用此方法制备的铝颜料具有良好的耐碱性。硅烷偶联剂和二氧化硅并不是简单的混合,而是彼此缩合形成了均一的杂化材料。     

反射隔热涂层用颜料的改性技术及研究进展

暴露在太阳光下的物体表面温度较高,影响了其正常的工作状态。在物体表面涂覆反射隔热涂料,因其施工方便、成本较低、隔热性能明显等优点而获得广泛应用。反射隔热涂料中颜料的性能是影响反射隔热涂层隔热性能的关键。然而已经应用的颜料颜色种类单一,反射性能也不够理想,为此需要对其进行表面改性。将常用反射隔热涂层用颜料的改性技术概括为两大类别,即表面包覆改性和离子掺杂改性。对表面包覆改性中的液相沉积法、机械球磨法和单体聚合法进行了介绍和国内外研究现状分析,并指出了适用情形。结合离子掺杂改性中的固相反应法和溶胶凝胶法特点,对各自的优缺点进行了分析和比较,着重介绍了固相反应法和溶胶凝胶法的主要适用情形和近年来国内外研究进展。从颜料的晶体结构出发,阐述了离子掺杂改性增强颜料近红外反射率的机理。最后,结合社会和经济的发展背景,对反射隔热涂层用颜料的改性技术发展趋势作出了展望。     

故宫古建筑用铁钉基体、铁锈剖析及缓蚀保护

目的 对故宫古建筑用铁钉进行检测并保护。方法 利用金相显微镜对铁钉基体进行金相组织分析,采用体视显微镜对锈层表面进行观测,借助扫描电镜、X-射线能谱仪(SEM-EDX)及X射线衍射仪(XRD),对锈蚀产物化学组成进行了成分测试。测定动电位极化曲线以研究硅酸盐复配缓蚀剂对铸铁电极预膜缓蚀后的电化学行为,通过加入聚乙二醇(PEG)的方法对硅酸盐复配缓蚀剂进行改性。结果 故宫古建筑用铁钉基体组织为球墨铸铁,表面锈蚀产物主要呈现红褐色及黑褐色,经分析主要由Fe2O3、Fe3O4和α-FeOOH组成,铁钉表面白色物的主要成分为CaCO3。极化曲线法测得硅酸盐复配缓蚀剂预膜后的缓蚀效率为20.53%,改性后的缓蚀效率达到81.20%。交流阻抗测试、耐盐雾测试及室外暴露测试都表明,改性后缓蚀剂具有一定的缓蚀性能。结论 故宫古建筑用铁钉表面锈蚀严重,需要通过系列保护手段减缓腐蚀速率。硅酸盐复配缓蚀剂预膜使用效果不佳,改性后的缓蚀剂对模拟铁钉的铸铁试样起到一定的缓蚀效果,且表面颜色变化小,满足铁质文物保护需求。     

改性水滑石的制备及对环氧富锌漆性能的影响

目的改善有机涂层和无机缓蚀剂相容性差的问题,实现缓蚀剂的可控释放,提高有机涂层的防护性能。方法用共沉淀方法将缓蚀剂钼酸根离子插入镁铝水滑石中,并用硅烷偶联剂KH560对其表面接枝改性来提高填料在富锌涂层中的分散性。结果 XRD、FTIR光谱分析结果表明,水滑石的层间距离增大,钼酸根成功装载进水滑石层中,在水滑石表面成功接枝硅烷偶联剂KH560。结论通过将该填料添加到环氧富锌漆中,发现涂层的附着力、柔韧性均没有发生明显的下降,表明填料在环氧富锌涂层中分散均匀,对涂层的力学性能影响较小。结合电化学阻抗谱技术对比研究添加填料与未添加填料的涂层浸泡在Na Cl溶液中的腐蚀行为,表明了该填料的添加可以提高富锌漆的耐腐蚀性能。     

金红石型云母钛珠光颜料的合成及表征

采用液相沉积法,使TiCl4溶液在78℃和pH=2.0条件下水解生成水合TiO2纳米颗粒,并在云母表面形成包覆膜,经过水洗、抽滤、烘干,以8℃/min的升温速率分别加热到600℃和800℃并保温0.5 h,得到色泽纯正、鲜艳、遮盖率高、耐候性好的金红石型珠光颜料.利用X射线衍射仪(XRD)分析测试表明,在包覆TiO2之前用适量的SnO2对云母片表面进行预处理能有效地提高TiO2颗粒在煅烧过程中金红石型的转化率;利用扫描电镜(SEM)对珠光颜料的表面结构进行测试,结果显示所制得的云母珠光颜料的包覆膜平整致密,TiO2粒径分布在30～40 nm之间.     

表面改性方法

0 前言 目前的热处理技术-表面改性技术被归纳成可谓“高性能化·复合化”的概念。也就是说,过去通过对零件进行渗碳淬火、渗氮、高频淬火等硬化处理来提高其强度和耐摩擦、耐磨损性能。可是,根据零件的高性能要求,今后将采用各种硬化处理来提高它的强度,采用形成干式覆膜、镀膜、渗硫覆膜,MoS_2覆膜、磷酸盐覆膜等各种润滑膜的方法来提高其耐摩擦、磨损性能。也就是根据不同目的考虑使用不同的处理方法。这里,介绍几种最近热处理-表面改性技术中常提及的处理方法。     

盐湖水中包铝对超硬铝合金基材的保护作用

利用带包铝LC4铝合金在东部地区海水、西部地区盐湖水、中部地区淡水中的暴露腐蚀试验,对盐湖水中包铝对铝合金基体的保护作用行为进行了探讨,得到带有包铝的LC4铝合金在水系统中的腐蚀规律.经过半年和一年的腐蚀试验表明,在不同的水介质中包铝对铝合金基材的保护作用表现不同.在海水和淡水中,包铝层可以对铝合金基材起到完全的保护作用,使基材免遭腐蚀;而在盐湖水中,半年时LC4铝合金表面尚有包铝存在,而一年时LC4铝合金表面包铝已完全消耗至尽,LC4的基体发生严重腐蚀.     

水溶性聚苯胺对铸铁的缓蚀作用

利用水溶性聚苯胺作为铸铁的缓蚀剂,采用全浸腐蚀失重法和扫描电子显微镜(SEM)研究了缓蚀剂在0.2mol/L硫酸溶液中对铸铁的缓蚀能力。结果表明,缓蚀率随缓蚀剂浓度的增加而升高,随浸泡时间的延长和温度的升高而降低。15℃和55℃时缓蚀剂在铸铁表面的吸附行为遵循Langmuir等温吸附线,吸附平衡常数分别为9.67和2.59。SEM观察结果表明,0.2 mol/L硫酸溶液中添加缓蚀剂对铸铁表面的腐蚀起到了良好的保护作用。     

Optimization of sol-gel coatings on the surface of aluminum pigments for corrosion protection

Encapsulated aluminum pigments were prepared by sol-gel method using tetraethoxysilane (TEOS) and vinyltriethoxysilane (VTES) as precursors. The reaction conditions were optimized and the aluminum pigments prepared under the optimum conditions were characterized by Fourier transformation infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Subsequently the stability of the aluminum pigments in acid and alkaline aqueous media was examined. It was found that both TEOS and VTES hydrolyze and condense to form a dense netlike layer on the surface of aluminum pigments. XPS analysis shows that TEOS-VTES successfully bonded to Al surface. The 0.64 eV shift of Al 2p binding energy indicates a new Si-O-Al bond formed on Al surface. The corrosion protection efficiencies of the TEOS-VTES-coated aluminum pigments prepared under the optimum experimental conditions reach 99.8% and 99.9% in acid media of pH 1 and alkaline media of pH 11, respectively, suggesting that TEOS-VTES sol-gel coatings can protect aluminum pigments well in corrosion media.     

闪光铝粉颜料的制备研究

建立了制备片状铝粉颜料的物理数学模型,以行星磨试验研究铝粉的研磨过程,提出了铝粉粉碎分三个阶段的观点;通过优化工艺参数制备出了形貌规整、表面光洁的闪光铝粉颜料。     

The effect of corrosion inhibiting pigments on environmentally assisted cracking of high strength aluminum alloy

The effects of some corrosion inhibiting pigments on environmentally assisted cracking of 7075-T76 aluminum alloy were examined in 3.5% NaCl (pH=6.2) solution. In order to study the inhibition mechanism of these pigments in environmentally assisted cracking of aluminum alloy, electrochemical polarization tests were carried out in 3.5% NaCl (pH=6.2 and 3) and 0.1 M HCl solutions respectively with the presence and absence of these pigments. The results showed that the effects of the pigments on environmentally assisted cracking of aluminum alloy were exhibited mainly at crack initiation and the early stage of crack propagation. A nontoxic compound, composed of phosphate, molybdate, citrate, and thiazole/imidazole derivatives, was a promising pigment to inhibit environmentally assisted cracking of the alloy.     

Aminomethylenphosphonsäuren als Korrosionsinhibitoren für Aluminiumpigmente in wäßrigen Medien

Aminomethylenephosphonic acids as corrosion inhibitors for aluminum pigments in aqueous media Flakelike aluminum pigments (aluminum content >99.5%) are corroded in aqueous alkaline mixtures of water and butyl glycol. Aminomethylenephosphonic acids inhibit this corrosion reaction. The temporal progress of the corrosion is determined by volumetric analysis of the evolved hydrogen. Direct comparison of aminomethylenephosphonic acids with analogous aminomethylenecarboxylic acids shows that the phosphonic acid group inhibits the corrosion significantly better than the carboxylic group. The actual corrosion inhibitors are in both cases (soluble) aluminum(III)-chelates, which are formed by a chemical reaction of the aminomethylenphosphonic resp.-carboxylic acids with the aluminum surface. This is proved by measuring the concentration of dissolved aluminum(III) in the corrosion medium with the help of atomic absorption spectroscopy and by using aluminum(III)chelates as corrosion inhibitors.     

Corrosion protection of aluminum pigments by sol-gel coatings

New sol-gel coatings for the corrosion protection of aluminum pigments were developed. To this end, the pigment particles are first coated with a silica layer by phosphoric acid-catalyzed sol-gel processing of Si(OEt)₄, to which either hexadecyltrimethoxysilane or dimethyldimethoxysilane is condensed. The coated pigments have excellent anticorrosive properties in alkaline solutions as well as under boiling water conditions.     

The Production of Coloured Anodic Films without the use of Dyestuffs

A full investigation has been made into the methods of obtaining coloured anodised aluminium by means of inorganic pigments and by some sealing treatments. The mechanism of absorption of inorganic pigments by the pores of the anodic film is discussed, and it is concluded that to obtain uniform colours it is necessary to control very carefully all the variables in the anodising and colouring techniques.

The majority of the colours described were subjected to both natural exposure and accelerated weathering tests, and some of the inorganic pigments were assessed by direct corrosion of coloured anodised panels in salt water. It was concluded that the most durable, light-fast pigments in the range of the present investigation are copper sulphide,§ ferric oxide, lead chromate, and prussian blue sealed in dichromate.     

Corrosion behavior of aluminum alloy 5754 in cement-based matrix-simulating nuclear waste disposal conditions

Depending on the lifetime and level of radioactivity of radioactive wastes, different disposal facilities are considered. Though low- and intermediate-level short-lived waste can be disposed in surface disposal facilities, deep geological disposal is considered for high- and intermediate-level long-lived waste. In France and Belgium, long-term disposal is studied in clay host rock media. For aluminum, the disposal concept is based on encapsulation of the waste in a cement-based matrix. It is also well-known that aluminum is prone to severe corrosion in sufficiently alkaline environments leading to possible hydrogen production. To ensure the safety of the disposal facilities and the integrity of the cement capsules, the amount of aluminum that is disposed in each waste package must be specified and is limited to mitigate the level of hydrogen production by aluminum corrosion. In the present study, the corrosion resistance of an aluminum alloy (grade EN-AW-5754/H111) in two different cement matrices was studied in different configurations at room temperature. In each case, the evolution of hydrogen production was monitored to address the corrosion rate variation versus time.     

航空航天铝合金构件装配孔钻削出口毛刺研究进展

航空航天制造业中存在大量的铝合金装配孔加工需求。装配孔主要通过钻削加工实现,加工中存在铝合金出口毛刺过大的问题。出口毛刺直接影响工件的精度、抗疲劳强度、装配性能,去毛刺工序会极大地增加工时和成本。因此有必要对铝合金装配孔钻削出口毛刺进行研究,实现对出口毛刺的控制。从铝合金钻削出口毛刺的类型和测量方法、形成机理和高度预测以及毛刺控制方法等方面进行了系统性的论述,以期为铝合金钻削加工出口毛刺的研究提供帮助。      

Investigation of corrosion behavior of aluminum flakes coated by polymeric nanolayer: Effect of polymer type

Protection of aluminum pigments from corrosion phenomenon has been extended by an encapsulating polystyrene (PS) and poly(acrylic acid) (PAA) nanolayers. Flakes were first coupled with 3-methacryloxypropyltrimethoxysilane (MPS) and in situ polymerizations of styrene and acrylic acid, initiating with Azobisisobutyronitrile (AIBN) were performed. The encapsulated flakes were characterized by Fourier transform infrared (FTIR), energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscope (TEM). Also, polymer chains were analyzed by gel permeation chromatography (GPC). Subsequently the chemical stability of the pigments in alkaline and acidic aqueous media was examined. Results indicated that polystyrene coating remarkably improved flakes’ anticorrosion property while PAA evolved hydrogen.