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1.
研究了以酒石酸钾钠、柠檬酸三钠作为络合剂的酸性硫酸盐溶液中的Cu-Zn合金镀层。探讨了电流密度、pH、温度对镀液分散能力和镀层组成的影响。在本实验条件下,添加剂的加入可以使镀液具有较好的分散能力和较高的电流效率。实验发现,在所研究的各种添加剂中,糖精、苯酚是加速剂,而硫脲、甘油是阻化剂。采用动电位极化和电化学阻抗谱方法,测定了Cu-Zn合金镀层在NaCl(φ=3.5%)溶液中的耐蚀性能。采用扫描电镜研究了添加剂对控制沉积质量的微妙作用。X-射线衍射分析表明,合金镀层的相结构是正交晶。在上述研究的基础上,提出了Cu-Zn合金电沉积的最佳组成和工艺控制参数。  相似文献   

2.
为了获得性能良好的含铬的锌合金镀层,在机械镀锌和机械镀Zn-Al合金工艺的基础上,通过调整活化剂和促进剂的种类及用量,开发了机械镀Zn-Cr及Zn-Al-Cr合金工艺。利用该工艺在钢基表面获得了Zn-Cr及Zn-Al-Cr合金镀层。对这些镀层进行了5%NaCl溶液喷雾腐蚀试验,并与机械镀锌层进行了对比。结果表明,Zn-Cr及Zn-Al-Cr合金镀层的耐蚀性能皆好于机械镀锌层。  相似文献   

3.
本文以沉积电流密度、电流效率、光泽度以及镀层表面形貌等为评价指标,研究了六种辅助络合剂对酒石酸钾钠体系电镀Cu-Zn合金的影响。结果表明,六种络合剂均可扩展沉积电流密度上、下限,其中草酸钾和乳酸对酒石酸钾钠体系电镀Cu-Zn合金的影响最为明显,前者明显改善电流效率及镀层光泽度,后者明显扩展沉积电流密度上、下限。二者浓度为30 g/L时,均可获得整平性较好的Cu-Zn合金镀层。  相似文献   

4.
研究了超声波条件下工艺参数对Co—Ni—B—Ce合金化学沉积速度的影响,讨论了温度、声强、超声波频率、镀液组成等对沉积速度的影响。研究发现:温度、超声波频率、镀液组成对沉积速度有较大的影响。超声波使Co—Ni—B—Ce化学沉积速度提高30%,在超声条件下,镀液的稳定性降低。随着声强的增加,镀液容易发生自分解,沉积速度迅速减小。通过对工艺的分析,得出了Co—Ni—B—Ce合金超声波化学沉积的最佳工艺参数。  相似文献   

5.
以ChCl-urea-ZnO-Cu2O低共熔溶剂为电解质在343 K镍基体上电沉积制备得到了铜锌合金镀层。伏安曲线测试表明在沉积过程中,镍基体能够诱导金属Zn发生欠电位沉积,从而实现了Cu-Zn合金的共沉积。同时研究了沉积电势对镀层成分和形貌的影响,结果表明:沉积电势由-0.85 V (vs Ag)增加到-1.3 V (vs Ag)时,合金镀层中Zn原子百分数从0升高到76.29%。在沉积电势为-1.10~-1.15 V范围内,Zn原子百分数为12.5%~20.81%时,镀层平整致密,颜色为金色,达到仿金镀的效果。  相似文献   

6.
以ChCl-urea-ZnO-Cu_2O低共熔溶剂为电解质在343 K镍基体上电沉积制备得到了铜锌合金镀层。伏安曲线测试表明在沉积过程中,镍基体能够诱导金属Zn发生欠电位沉积,从而实现了Cu-Zn合金的共沉积。同时研究了沉积电势对镀层成分和形貌的影响,结果表明:沉积电势由-0.85 V (vs Ag)增加到-1.3 V(vs Ag)时,合金镀层中Zn原子百分数从0升高到76.29%。在沉积电势为-1.10~-1.15V范围内,Zn原子百分数为12.5%~20.81%时,镀层平整致密,颜色为金色,达到仿金镀的效果。  相似文献   

7.
研究了一种含细化剂的低温镍-磷合金镀液,并对所得镀层的性能进行了测试。结果表明:最适宜的温度为40℃;含细化剂的低温镍-磷合金镀层的耐蚀性最优,镀层由细小、致密、平整、均匀的团聚状颗粒组成;细化剂不仅可以细化晶粒,还起到了共沉积促进剂的作用;该镀液具有较好的稳定性。  相似文献   

8.
低速电沉积钯镍合金工艺的研究   总被引:2,自引:0,他引:2  
通过极化曲线研究了钯、镍的电沉积行为.讨论了钯镍浓度比、pH值、电流密度、沉积电势等工艺参数对低速电沉积钯镍合金组成的影响.结果表明:与钯相比,镍的极化大,极化度也大;电沉积合金时,钯催化镍的沉积,而镍阻化钯的沉积.合金组成是各工艺参数的函数,镀液中钯、镍离子浓度比是影响合金成分的主要因素.随着镀液中Ni/Pd值的增大,合金中镍含量呈线性增加;pH值升高,合金中镍含量降低;电流密度增大或者沉积电势负移,合金中镍含量增加;沉积电势对合金成分的影响更显著,成分更易控制.  相似文献   

9.
就镍钨(D)合金刷镀中电极运动速度,施镀电压两个参数对结合力及硬度的影响进行了试验,从而得到镍钨(D)合金镀液的优化工艺参数,通过优化试验,提出了获得最高硬度及最佳结合力镀层的施镀工艺。  相似文献   

10.
通过调整镀液成分,优化温度、pH、施镀时间等工艺参数,获得了在玻璃基体沉积光亮Ni-P合金镀层的化学镀工艺;分析了镀层含磷量以及基体表面性质等对镀层光亮度和结合力的影响;性能测试结果证明镀层有较好的光亮度和结合力,磷的质量分数为10%~11%。  相似文献   

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12.
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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17.
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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