混合电路外壳引线局部镀金技术研究

混合电路外壳引线多、体积大,用整体镀金技术导致成本加大,而封装时只需引线镀金.采用外壳整体镀镍后引线部分镀金工艺可实现这一要求.但镍层的电极电位必须与金的电极电位相近,防止金被镍置换.研究给出了镀镍的方法和镀金液的配方,效果十分良好.     

高温除氢对镀金层表面可焊性的影响

以4J29可伐合金为基材进行镍/金/镍/金交叉电镀,采用声扫显微镜、扫描电子显微镜、能谱仪、聚焦离子束等手段研究了高温除氢对镀金层表面可焊性的影响。提高除氢温度有利于减少封装外壳内部的氢含量,但会促使镀镍层中的镍元素向镀金层扩散。当除氢温度为150℃时,镀金层与镀镍层结合处检测出镍元素;当除氢温度达350℃时,镀金层表面检测出镍元素;当除氢温度达450℃时,镀金层表面的镍多达21.32%(原子分数),并发生氧化。高温除氢使得镀金层成分和结构发生变化,致使镀金层表面焊料流散性变差,焊接孔隙率增大,焊接可靠性下降。     

混合电路引壳引线局部镀金技术研究

混合电路引壳引线多、体积大,用整体镀金技术导致成本加大,而封装时只需引线镀金。采用外壳整体镀镍后引线部分镀金工艺可实现这一要求。但镍层的电极电位必须与金的电极电位相近,防止金被镍置换。研究给出了镀镍的方法和镀金液的配方,效果十分良好。     

专利实例

化学镀两则2006301化学镀金本发明是为了解决在镍上焊接时,焊锡与镍之间的脱离问题,多应用导电线路上。具体做法是,在导电的线路上先镀一层镍作为底层,对镀覆镍的表面进行金催化活化或钯催化活化处理,然后化学镀金。或者在镀镍表面先化学镀钯,再化学镀金。这样获得的化学镀金层     

防扩散镀层的新工艺方向

镀金制品采用镀镍防扩散层可以防止底层的铜与金层的相互扩散。西欧国家对与人体直接接触的金属消费品规定了镍释出率和标准，因而提出代镍的防扩散层工艺。     

铍青铜零件电镀金工艺

在铍青铜基体上采用镍作为中间层然后镀金是传统的镀覆方法.有些应用场合不允许采用镀镍而直接镀金,必须解决镀层与基体结合力的问题.分析铍青铜的特性和镀金层结合力不良的原因,提出了一种铍青铜直接电镀金的工艺流程和工艺参数,包括热处理疏松氧化层、微腐蚀、除钝化膜、镀金及封闭处理等工序,解决了铍青铜氧化层的去除及镀金层与基体结合...     

工艺参数对印刷线路板表面化学镀镍/置换镀金层性能的影响

分析了工艺参数(如温度、pH值、沉积时间等)的变化时印刷线路板(PCB)表面化学镀镍/置换镀金层性能的影响。结果表明:工艺参数对镀层性能具有较大影响。在此基础上优化了化学镀镍/置换镀金工艺,获得了性能良好的镍/金镀层。     

非水溶液预镀镍在钛合金电镀前处理中的应用

回顾了多种钛合金电镀前处理的工艺方法。介绍了一种在TC4钛合金、TA1工业纯钛上获得耐磨、可焊的镀镍/金工艺,其流程主要包括除油、酸蚀、活化、预镀镍、电镀镍、化学镍和电镀金。试验了二甲基亚砜、乙二醇–醋酸–乳酸、乙二醇–柠檬酸等3种非水溶液体系预镀镍工艺。结果发现,采用乙二醇–柠檬酸体系预镀镍后所得金、镍镀层与钛基材结合良好,经过5次-65~200°C冲击循环以及多次"250°C-冷水"淬火试验后均无起泡、开裂,正常的摩擦试验后镀层没有被破坏。该工艺对解决钛合金材料的可焊性、导电性、耐磨性等问题不失为一种新的尝试,值得进一步的研究。     

工程塑料表面化学镀金工艺

介绍了工程塑料表面两步法化学镀金工艺：先进行化学镀镍,然后利用镍和金的置换反应化学镀金。通过讨论温度、pH对镀层的影响,确定最佳微蚀液为双氧水与硫酸的体积比为1：4的混合液。镀镍与镀金最佳温度都为85-90℃,最佳pH分别为4．7～4．9、4．4～4．8。说明了几点注意事项。实际应用表明,该镀金层结合力强,具有较好的机械强度与耐磨性,空隙小,表面均匀、光洁,金的纯度可达99．9％。提出了对塑料表面镀金工艺还需深入研究的几个方面。     

银合金装饰品的镀金工艺

简介了银合金基体镀金的工艺流程、配方及工艺要点。氰化物预镀铜打底用以提高镀层与基体结合力,酸性光亮镀铜提高产品亮度;光亮镍镀层做防扩散层;酸性镀金代替碱性镀金可以提高金镀层的硬度和耐磨性。     

Insect antifeedant properties of anthranoids from the genusVismia

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.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

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.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

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.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

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.     

2007～2008年世界塑料工业进展

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.     

2005～2006年国外塑料工业进展

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。