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1.
0前言 锌-铁合金镀层不仅防护性能优于普通镀锌与热浸镀锌层,而且还能提高对漆膜的结合力,具有良好的焊接加工性、抗蠕变性、易磷化性及抗蚀性。锌-铁合金镀层的磷化处理,能生成一种稳定的保护膜,提高涂层与基体镀层的结合力。  相似文献   

2.
电镀锌合金的发展   总被引:3,自引:0,他引:3  
比较了锌-镍合金、锌-铁合金及锌镀层的性能,指出锌合金钝化膜的高温抗蚀性与二次加工后的抗蚀性比锌镀层有很大提高,介绍了电镀锌-镍合金与电镀锌-铁合金的工艺,并突出介绍其工艺特点,综述了电镀锌合金及其钝化工艺在近年来的发展状况。  相似文献   

3.
观察了镁-锂合金锌系磷化膜和锰系磷化膜的宏观形貌及微观形貌,分析了2种膜层的化学组成,通过极化曲线、交流阻抗对比了基体、锌系磷化膜、锰系磷化膜的电化学性能,并比较了2种膜层的综合性能.结果表明:锌系磷化膜与锰系磷化膜对镁-锂合金基体具有较大的防护作用,尤其是锌系磷化膜膜厚,膜电阻大,自腐蚀电流密度小,耐蚀性更优.  相似文献   

4.
采用电沉积方法从碱性镀液中制备γ相Zn-Ni合金镀层,应用扫描电子显微镜、X-射线衍射仪、电化学测量技术对Zn-Ni合金镀层的微观结构和耐蚀性能进行了研究。结果表明,Ni-Zn合金镀层的腐蚀性与其微结构密切相关。Zn-Ni合金镀层的晶型为γ相,合金镀层中镍和锌的质量分数分别为15.98%和84.02%;锌-镍合金镀层中原子堆积方式为正四面体形。在5%氯化钠溶液中,γ相Zn-Ni合金镀层与锌镀层的电化学测试结果表明,在0-10Hz低频率区,γ-相Zn-Ni合金镀层的交流阻抗谱的实部值为镀锌层的7.2倍;腐蚀电位比锌层增加了0.1279V,镀锌层的Jcorr是γ相Zn-Ni合金镀层的5.78倍。  相似文献   

5.
探讨了氯化物体系Zn Fe合金电镀液中各组分及其他工艺参数对镀层中铁含量的影响。在最佳Zn Fe合金电镀工艺条件下 ,得到了含铁量为 0 41 %的Zn Fe合金镀层 ,经银白色钝化后的该种合金镀层的抗蚀能力约为同厚度纯锌镀层的 2~ 3倍。研究同时表明 ,Zn Fe合金镀液具有良好的分散能力、覆盖能力和整平能力 ,电镀电流效率高 ,镀层性能优良  相似文献   

6.
钢铁另件镀锌后一般总要用含有六价铬的溶液进行化学处理,使锌镀层表面生成一层钝化膜,以便达到提高锌镀层的抗蚀能力,改进涂料与底金属的结合力和增加装饰性等目的.根据钝化膜的颜色和钝化工艺,钝化膜常常可以分为彩色钝化膜和白色钝化膜两种.使用经验和盐雾试验都表明,彩色钝化膜经过漂白处理后,膜的抗蚀能力大大下  相似文献   

7.
抗蚀用锌合金电镀   总被引:2,自引:0,他引:2  
抗蚀用锌合金电镀蔡积庆(南京无线电八厂,210018)1前言在汽车和建筑等工业领域中,锌镀层曾是铁制零部件的抗蚀性保护镀层。然而在严酷的腐蚀环境下,锌被迅速地侵蚀损耗,丧失保护性能,为此要求较厚的镀锌层。但是厚镀层不仅会提高成本,而且还会导致以后的焊...  相似文献   

8.
镀锌层中含有微量的钛,可以增加镀层的抗腐蚀性能。使用一种含氯化钛0.4M/l,氯化锌0.4—1.2M/l的甲酰胺电解液,溶液中还含有14W/l的水,可以改善溶液的导电性。在溶液温度为35℃,电流密度为4A/dm~2的条件下,10分钟可以沉积9μ的含钛12%的镀锌层。镀锌层中含有钛,可使镀层的抗蚀性大约提高一倍。试验表明,这种锌钛合金镀层,每年  相似文献   

9.
镀锌工艺的选择与管理   总被引:1,自引:1,他引:1  
镀锌工艺的选择与管理周长虹光亮镀锌是黑色金属的优良防护──装饰性镀层,应用广泛,是我国最大的镀种。镀液主要为钾(钠)盐镀锌;锌酸盐镀锌和氰化物镀锌,经过铬盐钝化的镀层,有良好的抗蚀性,各种颜色的钝化膜不仅增加了装饰效果,也提高了镀锌层的耐蚀性。近年来...  相似文献   

10.
锰系中温黑色抗蚀磷化生产实践   总被引:1,自引:1,他引:1  
锰系中温黑色抗蚀磷化工艺对传统的锰系磷化工艺进行了改进。介绍了磷化溶液的配制、各成分作用、管理维护及磷化后处理与磷化膜性能检测。该工艺降低了磷化温度,提高了生产效率,能获得良好的磷化膜层。  相似文献   

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Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.  相似文献   

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14.
Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.  相似文献   

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In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.  相似文献   

18.
Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.  相似文献   

19.
收集了2007年7月~2008年6月世界塑料工业的相关资料,介绍了2007~2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.  相似文献   

20.
收集了2005年7月~2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、通用热固性树脂(酚醛、聚氨酯、不饱和树脂、环氧树脂)、特种工程塑料(聚苯硫醚、液晶聚合物、聚醚醚酮)的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。  相似文献   

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