共查询到20条相似文献,搜索用时 62 毫秒
1.
2.
3.
4.
考察了镀液中FeSO4的质量浓度对合金镀层沉积速率的影响,并通过金相显微镜对镀层表面形貌进行观察;采用硬度计和实验室浸泡方法分别考察了镀层的显微硬度和耐蚀性.结果表明:当镀液中FeSO4的质量浓度小于2.0 g/L时,镀层的沉积速率虽然降低,但镀层的表面更加均匀、致密,表面质量更好,镀层的显微硬度和耐蚀性也得到提高;当... 相似文献
5.
6.
研究了峰值电流密度对脉冲镍钴合金纳米镀层的成分、晶粒尺寸、显微硬度、抗拉强度的影响.结果发现:在一定范围内,峰值电流密度的增大,可以降低镀层钴含量、表面粗糙度和晶粒尺寸,使菜花胞状结构更明显,提高镀层显微硬度(最高可达600 kg/mm2)和抗拉强度(最高可达1 200 MPa).然而,峰值电流密度太大又会使显微硬度和强度下降.与采用类似方法制得的纯镍纳米镀层相比,镍钴镀层的显微硬度并未明显升高.这说明在该纳米材料中,固溶强化效果并不很明显,而以细晶强化为主. 相似文献
7.
采用NiSO_4·6H_2O与CoSO_4·7H_2O的质量浓度比不同的镀液在黄铜上喷射电沉积Co–Ni合金,研究了电流密度对Co–Ni合金镀层表面形貌、元素组成、晶体结构、显微硬度和耐磨性的影响。结果表明:随着电流密度的增大,Co–Ni合金镀层的晶粒先细化后粗化,Co含量减小。镀层在Co含量高于85%时基本为密排六方(hcp)相,低于85%时为hcp和面心立方(fcc)两相共存。镀层的晶粒越细,则显微硬度越高,耐磨性越好。在CoSO_4·7H_2O和NiSO_4·7H_2O的质量浓度分别为200 g/L和100 g/L的条件下,镀层受电流密度的影响较小,Co含量稳定在96%左右,表面均匀致密,显微硬度高达425 HV,耐磨性较好。 相似文献
8.
研究了工艺条件对镍-钨-铁-钴合金镀层组分、显微硬度及阴极电流效率的影响.结果表明,镀液θ为60 ~ 70℃、pH为6.0 ~6.5、Jk为2~ 10 A/dm2、15 ~ 25 mL/L调色剂,在此条件下得到的合金镀层效果最接近硬铬镀层;提高镀液θ和pH,增加调色剂质量浓度,有利于阴极电流效率的提高;升高镀液θ,提高Jk和镀液中调色剂的质量浓度,降低镀液pH,镀层中的钨和显微硬度增加.还研究了热处理工艺对镀层显微硬度的影响,在350~400℃条件下热处理3h,镀层显微硬度可达1065 HV. 相似文献
9.
电沉积镍铁钨纳米晶合金及其表征 总被引:2,自引:1,他引:1
在含有FeSO4·7H20、NiSO4·6H2O、Na2WO4·2H2O、Na3C6H5O7·2H2O和YC-4添加剂的溶液中,电沉积制备了不同钨含量的镍铁钨合金,对所得镀层的化学组成、表面形貌、微观结构,显微硬度及耐蚀性进行了表征.随着镍铁钨合金镀层中钨含量的增加,其微观结构由晶态转变为非晶态.钨质量分数为21%的镍铁钨合金镀层表观光亮光滑,具有致密的纳米晶结构,其晶粒尺寸为30~40 nm,即使不通过热处理,也具有很好的显微硬度和耐蚀性.该工艺可望取代传统镀铬工艺. 相似文献
10.
在TC4合金表面分别制备了Cu/micro-WC复合镀层和Cu/nano-WC复合镀层。比较了两种复合镀层的表面形貌、化学成分和显微硬度,同时分析了两种复合镀层的摩擦特性。结果表明:两种复合镀层都由Cu、W、C元素组成,显微硬度都明显低于TC4合金的显微硬度;摩擦试验前后,两种复合镀层表面轮廓曲线的形态都存在明显的不同;与Cu/micro-WC复合镀层相比,Cu/nano-WC复合镀层的表面形貌较好,W元素的质量分数较高,耐磨性较强。 相似文献
11.
12.
M. S. J. Simmonds W. M. Blaney F. Delle Monache M. Marquina Mac-Quhae G. B. Marini Bettolo 《Journal of chemical ecology》1985,11(12):1593-1599
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.
14.
Cheng-Le Zhao Shane Porzio Alan Smith Haiyan Ge H. T. Davis L. E. Scriven 《Journal of Coatings Technology and Research》2006,3(2):109-115
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
15.
16.
17.
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. 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.
中蓝晨光化工研究院有限公司《塑料工业》编辑部 《塑料工业》2009,37(3)
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.
中蓝晨光化工研究院《塑料工业》编辑部 《塑料工业》2007,35(3):1-25,67
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