低应力Ni–W/Ni叠层微模具的制备与特性

采用UV-LIGA技术和Ni–W/Ni叠层电镀方法,在微喷嘴模具上制备出低应力Ni–W沉积层。研究了热处理条件对低应力Ni–W电沉积层硬度的影响。考察了沉积态及热处理态的Ni–W层、Ni层的耐磨性。结果发现,热处理后Ni–W/Ni叠层微模具界面结合良好,在干摩擦条件下,经过热处理的Ni–W层的耐磨性是Ni层的6倍;在550°C、2h真空热处理条件下,Ni–W电沉积层应力最低,为230MPa,硬度大于950HV。     

化学镀Ni–P合金镀层热处理及磨损性能的研究

在20CrMnTi低碳钢上实施渗碳工艺,再化学镀Ni–P合金,研究了不同热处理温度对Ni–P合金镀层结构、显微硬度和结合力的影响,探索了不同载荷下Ni–P合金镀层的耐磨性,并与渗碳层进行了对比。结果表明,随着热处理温度的提高,Ni–P合金镀层由非晶态转变为晶态,并伴随着新相Ni3P的析出。镀层结合力随热处理温度的升高不断增强,而镀层显微硬度和耐磨性则先增大后减小,并在400°C时达到最大值。在本试验条件下,化学镀Ni–P合金镀层的耐磨性优于渗碳层。     

电动汽车用铜质零件表面耐磨镀层的制备及性能

为了提高电动汽车用铜质零件的耐磨性,利用电沉积方法在紫铜基材表面制备出Ni-W合金镀层。基于正交试验优化得到了最佳的工艺条件,并对最佳工艺条件下制备的Ni-W合金镀层的性能进行了测试。结果表明:最佳工艺条件下制备的Ni-W合金镀层为非晶态结构,表面平整,结构致密;平均表面硬度为4 413 MPa,是紫铜基材的4.5倍;耐磨性优于紫铜基材的,相同条件下的磨损失重量较低。     

电沉积Ni-Co合金的研究

研究了氨基磷酸盐电沉积Ni-Co合金电解液组成及工艺条件对沉积层中Co含量的影响.并测定了Ni-Co合金沉积层中Co含量与Ni-Co与硬度的关系,以及影响Ni-Co合金沉积层内应力的因素.实验结果表明,将一定量的Co引入Ni沉积层,可以显著地提高其硬度;当在电解液中添加一定量的Ni-1添加剂后,能使Ni-Co合金沉积层的内应力为零.这些有益的实验结果为电铸加工使用寿命长、机械性能好的模具提供了一定的依据.     

Ni-W纳米结构梯度镀层耐热及高温氧化性能

对Ni-W纳米结构梯度镀层进行热处理,结果表明：400 ℃热处理1 h后,镀层结构未发生改变,硬度高达Hv1300,优于硬Cr镀层;600 ℃热处理1 h后,镀层结构由原来的以Ni为溶剂、W为溶质的固溶体转变为存在单一相Ni和W的多晶结构.热处理并未改变Ni-W梯度镀层中W含量的梯度分布.Ni-W纳米结构梯度镀层具有优良的高温氧化性能,可用于高温氧化气氛中.     

热处理对哈氏合金C-276堆焊层性能的影响

由实验结果得到在焊态和热处理态的哈氏合金C-276堆焊侧弯结果均合格;增加保温时间,SWAM堆焊侧弯试验不合格,而ESSW堆焊侧弯仅有32h热处理试样不合格;焊态试件硬度符合要求,热处理后堆焊层硬度有所提高;应力腐蚀试验合格,SMAW堆焊和ESW堆焊层腐蚀率在焊态和热处理下均合适.哈氏合金C-276堆焊层在焊态和690...     

Al2O3-(W,Ti)C/Al2O3-TiC对称型叠层陶瓷的结构设计和力学性能

为提高陶瓷材料表面的硬度和韧性,热压烧结制备了Al2O3-(W,Ti)C/Al2O3-TiC对称型叠层陶瓷材料.研究了该叠层材料的层厚比和层数对材料表层的硬度、断裂韧性的影响.此外,通过压痕裂纹法的测量和有限元计算均可以得到叠层陶瓷材料表面层的残余应力值,两种方法获得的残余应力值符合得很好.通过有限元计算还可以得到叠层陶瓷材料不同层内的残余应力分布特征.对比实验表明:叠层陶瓷材料表面层较之相应单一材料而言,具有更高的硬度和断裂韧性.叠层陶瓷材料中残余压应力的存在,是叠层陶瓷材料表面层具有高硬度、高韧性的原因.而且通过改变叠层材料的层厚比和层数可改变叠层材料残余应力的分布.     

兆声功率密度对同轴兆声辅助喷射电沉积镍的影响

[目的]金属微器件在电沉积过程中往往会产生较大的残余应力,对微器件的尺寸精度、力学性能和良率产生不利影响。[方法]为降低镀层的残余应力,在喷射电沉积镍过程中施加同轴兆声辅助。研究了兆声功率密度对Ni镀层形貌、表面粗糙度、显微硬度和残余应力的影响。[结果]施加同轴兆声辅助后,所得Ni镀层的宏观和微观形貌都有所变差,表面粗糙度略微增大,显微硬度变化不大,但残余应力显著降低。当兆声功率密度为10 W/cm²时,Ni镀层的残余应力最低,比无兆声辅助时所得Ni镀层低了37.75%。[结论]在电沉积过程中施加兆声辅助能够有效降低镀层的残余应力。     

Ni—Fe—P／Al2O3复合镀层的硬度和耐磨性

对不同工艺条件下获得的Ｎｉ－Ｆｅ－Ｐ／Ａｌ２Ｏ３复合镀层的显微硬度及其耐磨性进行了研究。结果表明,复合层的显微硬度和耐磨性随Ａｌ２Ｏ３复合量,镀液中ＮａＨ２ＰＯ２·Ｈ２Ｏ浓度,电流密度以及施镀温度的改变而变化。在改变工艺参数的过程中,复合镀层显微硬度比Ｎｉ－Ｆｅ－Ｐ电沉积层平均高约Ｈｖ１００￣１６０。     

代铬镀层--Ni-W、Ni-W-B非晶态合金镀层性能研究

通过在浓硝酸、ω=5％NaCl溶液c=1mol/L H2SO4溶液中的浸渍试验,研究了不同基体上的Ni-W非晶态合金镀层的耐蚀性;通过测定在ω=5％ NaCl溶液及c=1mol／1．的HNO3溶液、H2SO4溶液、HCl溶液中的阳极极化曲线,研究了Ni-W非晶态合金镀层薄膜本身的耐蚀性;采用线性极化方法对Ni—W—B非晶态合金镀层在u=5％ Na—Cl溶液、c=1mol／L H2SO4溶液及HNO3溶液中的腐蚀速度进行了测定,并测定了以上2种非晶态合金镀层的硬度与耐磨性.结果表明．非晶态的Ni—W、Ni-W-B镀层比晶态镀层的耐腐蚀性能要好．而Ni—W—B非晶态合金镀层比Ni—W非晶态合金镀层的耐蚀性能又明显提高;经热处理后,Ni—W—B非晶态镀层的硬度值明显高于Ni—W非晶态镀层,耐磨性能都提高了1倍以上Ni—W、Ni—W—B非晶态镀层极有望成为一种比较好的代铬镀层。     

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。