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1.
碱性锌—钛合金镀液中锌、钴含量的测定   总被引:1,自引:0,他引:1  
为获得耐蚀性良好的锌-钴合金镀层,必须维持镀液中的锌-钴含量在工艺范围内,采用EDTA滴定和分光光度相结合的方法测定碱性锌-钴合金镀液中的锌、钴含量。介绍了该方法的分析步骤,探讨了测量波长的确定,亚硝酸钠、镀液共存组分、酸度以及铜离子和铁离子等杂质对测量结果的影响。结果表明,在530nm波长下,钴浓度在0-3μg/mL范围内所测吸光度与钴浓度间的关系遵守比耳定律,该方法准确度高,回收率达97%-103.5%。  相似文献   

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首先利用酸性镀液中钴本身的颜色,以水作参比,在波长为520nm处,直接用分光光度法测定Co^2 含量,然后,在pH=5.5的条件下,以二甲酚橙作指示剂,用EDTA滴定锌钴求出锌钴合量,再用锌钴合量减去镀液中的钴含量从中得到锌的含量。方法简单快速,测量结果准确,能满足实际生产要求。  相似文献   

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为了获得耐蚀性良好的锌一铁合金镀层,必须维持镀液中锌、铁含量在一定的工艺范围内。采用EDTA滴定和分光光度相结合的方法测定碱性锌一铁合金镀液中的锌、铁含量,并优选出最佳测量波长。研究了酸度、显色剂浓度、共存组分及干扰元素对测量结果的影响;结果表明:铁在0~6μg/mL范围内遵守比尔定律。该方法简便快速、准确度高能满足实际生产的要求。  相似文献   

4.
二溴对甲偶氮羧光度法测定锌钴合金镀液中的钴   总被引:1,自引:0,他引:1  
研究了显色剂二溴对甲偶氮羧与钴的显色反应。pH=10的柠檬酸铵–氨水溶液中,钴与二溴对甲偶氮羧反应形成蓝色配合物,其最大吸收波长为660nm,表观摩尔吸光系数为1.77×104L/(mol·cm)。25mL溶液中的钴含量为0~80μg,符合比尔定律。该方法可用于锌钴合金镀液中钴的直接测定,相对标准偏差为1.4%~1.9%,回收率为98%~102%。  相似文献   

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介绍了铝合金电镀碱性锌-钴合金工艺。碱性锌-钴合金镀液具有优良的分散能力、深镀能力及较高的电流效率。得到的镀层脆性小,钴的质量分数低,容易钝化。  相似文献   

6.
简介了锌钴合金电镀工艺、镀液配方、镀液性能、钝化方法等。  相似文献   

7.
采用循环伏安法研究了氯化物体系中锌-钴合金电镀的电沉积过程,采用X-射线厚度和成分分析仪测量了锌-钴合金镀层的厚度和钴金属质量分数.试验表明,在氯化钾锌-钴合金电镀槽液可以电镀钴质量分数为0.2%~0.4%的锌-钴合金,钴添加剂的加入,能够使氢的析出电位负移,扩大了锌-钴合金沉积的电位区间范围.  相似文献   

8.
镍-钴合金镀液中镍、钴的快速测定   总被引:1,自引:0,他引:1  
李艳 《电镀与精饰》2004,26(5):29-31
研究了以EDTA作为显色剂,用双波长光度法测定镍一钴合金镀液中Ni^ 与Co^2 质量浓度的方法,选择并确定了测量波长,分析了溶液的pH值、显色剂的用量等对测量结果的影响,实验结果表明,该方法的准确度和精密度较高。  相似文献   

9.
在酸性氯化物槽液中可镀取光亮、整平的锌镍和锌钴合金镀层.阐述了工艺配方、操作条件、工艺流程、镀液维护与故障排除方法.所得镀层经过三价铬蓝色钝化处理后,外观和抗蚀性能都很好.  相似文献   

10.
介绍碱性无氰锌钴合金电镀工艺、镀层和镀液性能及槽液维护控制。镀层耐蚀性高,镀液稳定性好,是理想的锌合金镀层。  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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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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