碳钢表面铜-碳化硅纳米复合镀层的制备及其性能研究

在Q235碳钢表面先预浸镀铜,然后采用超声-电沉积方法获得Cu-SiC纳米复合镀层。研究了纳米SiC含量对纳米复合镀层表面形貌的影响,讨论了阴极电流密度、超声功率、温度和电沉积时间对复合镀层显微硬度的影响,获得了较佳的工艺条件:镀液中SiC纳米颗粒含量9g/L,阴极电流密度6A/dm2,超声波功率200W,镀液温度30°C,电沉积时间40min。在此条件下制备Cu-SiC纳米复合镀层,测试了镀层的结合力,并与普通铜镀层进行比较,研究了复合镀层的表面形貌、显微硬度以及在3.5%NaCl溶液中的电化学阻抗谱(EIS)。结果表明,所制备的复合镀层结合力良好,其表面颗粒尺寸在0.5～1.0μm之间(小于普通铜镀层的1～4μm),显微硬度和反应电阻分别为294.6HV和2446.5.cm2(大于普通铜镀层的162.0HV和1538.7.cm2)。Cu-SiC纳米复合镀层具有较好的机械性能和耐腐蚀性能。     

(Ni-W)-纳米Si3N4复合电镀工艺的研究

研究了(Ni-W)-纳米Si3N4复合镀层的共沉积条件,考察了电流密度、温度和时间等操作条件对镀层沉积速率和显微硬度的影响.结果表明,随着电流密度提高,复合镀层的沉积速率和硬度不断增加,但当电流密度达到16 A/dm2,镀层的硬度下降;合适的镀液温度为75℃左右,沉积时间约60 min.     

低温镀铁层显微硬度的研究

研究了pH值、温度、电流密度以及主盐的质量浓度对低温镀铁层显微硬度的影响。结果表明:电流密度为14A/dm2时镀层的显微硬度最高,电流密度为16A/dm2时镀层有针孔出现;随着pH值的增大,温度的升高或者镀液中主盐的质量浓度的增加,镀层的显微硬度降低。     

工艺参数对Ni-Fe-Co三元合金镀层形貌及耐蚀性的影响

通过电沉积方法在钢基体表面制备Ni-Fe-Co三元合金镀层。讨论了电流密度、温度、pH值对合金镀层表面形貌及耐蚀性的影响。结果表明:在电流密度6A/dm~2,pH值3.6,温度65℃的条件下,获得的合金镀层均匀致密,显微硬度较高且耐蚀性较好。     

电沉积Ni—Fe—P合金工艺研究

为改善Ｎｉ－Ｐ镀层性能，开发研究了Ｎｉ－Ｆｅ－Ｐ镀层。研究了镀液主要成分和工艺参数对镀层成分、沉积速度和显微硬度的影响。研究表明，Ｎｉ－Ｆｅ－Ｐ镀层中各元素的含量随镀液中相应盐浓度的增大而提高；低ｐＨ值和电流密度可适当提高镀层含磷量；高电流密度有利于铁的沉积；提高镀液温度和ｐＨ值加快沉积速度，却降低镀层硬度。较高的电流密度可获得较高的沉积速度和镀层硬度。     

峰值电流密度对脉冲电沉积Ni-Co-CNTs复合镀层机械性能的影响

研究了峰值电流密度对脉冲电沉积Ni-Co-CNTs复合镀层机械性能的影响。结果表明:当峰值电流密度升高时,镀层表面变得粗糙;随着峰值电流密度的增加,镀层中碳的质量分数先增加后下降,当峰值电流密度为80 A/dm~2时,镀层中碳的质量分数达到最大值;镀层的显微硬度和抗拉强度均在峰值电流密度为100 A/dm~2附近时达到其最大值,且高于直流电沉积时所得镀层的显微硬度值和抗拉强度值。说明采用脉冲电沉积工艺可以提高镀层的机械性能。     

(Ni-P)-WC纳米微粒复合电镀的研究

研究了WC纳米微粒质量浓度、阴极电流密度、pH值、温度、搅拌方式等工艺参数对(Ni-P)-WC纳米微粒复合镀层沉积速度的影响,并通过正交试验,确定了复合电镀的最佳工艺参数。对镀层的表面形貌、成分及不同热处理条件下的硬度进行了观察与测定,实验结果表明,镀层表面均匀,有质量分数为2．0％～3．5％的WC纳米微粒的镀层;热处理后硬度可达1240HV。     

电沉积Ni－Fe－P合金工艺研究

为改善Ｎｉ－Ｐ镀层性能，开发研究了Ｎｉ－Ｆｅ－Ｐ镀层。研究了镀液主要成分和工艺参数对镀层成分、沉积速度和显微硬度的影响。研究表明，Ｎｉ－Ｆｅ－Ｐ镀层中各元素的含量随镀液中相应盐浓度的增大而提高；低ｐＨ值和电流密度可适当提高镀层含磷量；高电流密度有利于铁的沉积；提高镀液温度和ｐＨ值加快沉积速度，却降低镀层硬度。较高的电流密度可获得较高的沉积速度和镀层硬度。     

Ni-SiC复合电镀工艺的优化及镀层结构表征

利用电沉积法制备出Ni-SiC复合镀层,研究了阴极电流密度、温度、pH、搅拌速率、表面活性剂等工艺参数对镀层显微硬度和沉积速率的影响,通过正交试验得出了最佳工艺参数:阴极电流密度4A/dm2,SiC微粒悬浮量60g/L,温度40℃,pH 2.5,搅拌速率300 r/min.用SEM、XRD和TEM分析了镀层的表面形貌、组织结构及镀层中粒子的分布,结果表明:SiC微粒均匀分布于复合镀层中,镀层表面平整光滑,显微组织均匀、致密,其显微硬度也较纯镍镀层有显著提高.     

硫酸盐镀液中紫铜电沉积Ni-Co/WC复合镀层的工艺条件优化

在硫酸盐镀液中加入纳米WC颗粒,通过电沉积在紫铜表面制备了Ni-Co/WC复合镀层.采用单因素分析法考察了镀液中纳米颗粒浓度、温度、阴极电流密度和搅拌速度对复合镀层硬度的影响,确定了电沉积Ni-Co/WC复合镀层的最佳工艺条件为:镀液中纳米颗粒浓度11 g/L、温度60℃、阴极电流密度5 A/dm2、搅拌速度450 r...     

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。