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1.
化学镀Ni—Sn—P合金镀层耐蚀性的研究(II)   总被引:2,自引:1,他引:1  
研究了化学镀Ni-Sn-P合金镀层的耐蚀性,并同高磷Ni-P合金(11.9wt%P)镀层进行了比较。结果表明:Ni-Sn-P合金镀层孔隙率低,在酸性、中性和碱性介质中的耐蚀性优于Ni-P合金镀层。  相似文献   

2.
化学镀Ni-Sn-P合金镀层耐蚀性的研究(Ⅱ)   总被引:4,自引:0,他引:4  
研究了化学镀Ni-Sn-P合金镀层的耐蚀性、并同高磷Ni-P合金(11.9wt%P)镀层进行了比较。结果表明:Ni-Sn-P合金镀层孔隙率低,在酸性、中性和碱性介质中的耐蚀性优于Ni-P合金镀层。  相似文献   

3.
钨对化学镀Ni-W-P合金镀层结构及性能的影响   总被引:4,自引:0,他引:4  
通过不同的化学镀工艺配方,获得了4种不同钨含量的化学镀Ni-W-P三元合金镀层.研究了钨含量对镀层结构、硬度及在5%H2SO4溶液中耐蚀性的影响规律.研究发现,化学镀Ni-W-P三元合金镀层的结构受镀层中钨含量的影响较大,非晶态Ni-W-P三元合金镀层所需磷含量较非晶态Ni-P二元镀层所需磷含量要低,并且钨含量越高,所需磷含量越少;镀层硬度随镀层结构从非晶态→混晶态→纳米晶态转变而增加;镀层的耐蚀性随镀层中钨含量增加而变好,且非晶态镀层较混晶态和纳米晶态镀层更易形成钝化区.  相似文献   

4.
用线性极化法和孔蚀实验评定了镀覆在铝材上的4种磷含量和磷分布不同的化学镀镍磷合金镀层在10%H2SO4,10%NaOH,10%HCl和3.5%NaCl溶液中的耐蚀性,观察的镀层包括高磷(HP)、低磷(LP)、以及含磷量从镀层底部到顶面为高到低(HL)和为低到高(LH)的4种镀层。结果发现,在H2SO4和NaOH溶液中LH和HL镀层的耐蚀性最好,在HCl溶液中LH和HP最佳,而LP镀层则在上述3种溶液中都是最差的。4种镀层的耐孔蚀性由高至低依次为LH、HP、HL和LP。文中还讨论了耐蚀性机理。  相似文献   

5.
多种化学镀镍层性能的对比实验   总被引:1,自引:0,他引:1  
对酸性、碱性及多元化学镀镍层的性能进行了对比.采用失重法测试了3种镀层的耐蚀性,测定了镀层在HCl溶液及NaCl溶液中的极化曲线,分析了3种镀层在不同温度下的硬度变化,测定了镀层热处理前、后的X射线衍射图.结果表明:多元Ni-Cu-P镀层的耐蚀性最佳,酸性镀镍层次之,碱性镀镍层最差:在400~500℃热处理后,多元Ni-Cu-P镀层的硬度最高,其耐磨性很好.  相似文献   

6.
化学镀镍—磷合金中磷的含量对镀层性能的影响   总被引:1,自引:0,他引:1  
本文采用酸性化学镀镍-磷合金电解液,通过改变还原剂浓度、稳定剂浓度、pH值及操作温度,制备了含磷量为6%、8%及12%的镍-磷合金镀层。通过大量实验证明,镀层的耐蚀性、耐磨性及硬度与镀层中的磷含量有直接关系。随着含磷量的增加,镀层的耐蚀性及耐磨性提高,经400℃热处理1h后,镀层的耐蚀性下降,而耐磨性提高。通过改变镀层中的磷含量可以提高其硬度,其中含磷量为8%、400℃下热处理1h的镀层硬度最高。  相似文献   

7.
化学镀镍-铜-磷三元合金工艺的研究   总被引:1,自引:2,他引:1  
为提高化学镀镍-磷合金镀层的性能及获得多种性能的合金镀层以拓宽其应用范围。在化学镀镍-磷合金液中加入硫酸铜制得镍-铜-磷三元合金。研究了镀液中硫酸镍、次磷酸钠、柠檬酸钠、硫酸铜、稳定剂、光亮剂的含量以及pH值和温度等因素对合金镀层的外观、沉积速度及铜含量的影响。通过5%氯化钠溶液和10%硫酸溶液浸泡试验比较了所得镍-铜-磷合金镀层与镍-磷合金镀层以及前人制得的镍-磷合金镀层的耐蚀性,同时比较了上述镀层的其它性能。结果表明,所得镍-铜-磷合金镀层的耐蚀性、外观、结合力、孔隙率、沉积速度、硬度和耐磨性等性能优于镍-磷合金及前人制得的镍-铜-磷合金镀层。  相似文献   

8.
镁合金化学镀工艺研究   总被引:6,自引:2,他引:6  
向镀液中加入氰化物,采用硫酸镍代替碳酸镍作为镍源,开发出一种镁合金化学镀镍新工艺。测定了该镀层中的磷含量及其耐蚀性、显微硬度、结合力,并用扫描电镜对其表面形貌进行了观察结果表明,该镀层结合力合格,硬度远高于镁合金基体,且与普通化学镀层相当;该镀层属高磷镀层,耐蚀性较好,但与普通基体材料上的化学镀层相比要差一些。该工艺使镁合金化学镀成本大大降低,工艺得到简化。  相似文献   

9.
柠檬酸对Ni-P合金化学镀沉积速度和镀层性能的影响   总被引:3,自引:1,他引:3  
研究了柠檬酸浓度对乙酸盐缓冲体系Ni-P合金化学镀沉积速度、镀层含磷量及其耐蚀性与结构的影响,并对镀层在镀态下和经热处理后的耐蚀性与结构进行了比较。结果表明,随柠檬酸浓度的增加,沉积速度先增加后l牵低,而镀层中磷含量则先降低后增加;镀态时高磷合金为非晶态结构且具有较好的耐蚀性,中磷合金则为非晶 微晶结构,耐蚀性较低,而所有镀层经350℃热处理1h后,结构都转变为晶态,且耐蚀性明显提高。  相似文献   

10.
45号钢表面化学镀镍磷合金   总被引:2,自引:0,他引:2  
在45号钢表面化学镀镍磷合金,获得含磷10%(质量分数)的镍磷合金镀层,比较了其与2Cr13不锈钢的耐磨性及在不同腐蚀介质中的耐蚀性,结果表明,含磷10%的镍磷合金层的耐磨,耐蚀性均优于2Cr13不锈钢。  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   

13.
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   

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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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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   

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