Q235钢表面不同高分子涂层耐蚀性对比

对Q235碳钢进行表面处理,涂覆环氧树脂(EP)和聚乙烯(PE)涂层来提高其耐腐蚀性能。采用扫描电子显微镜(SEM)和X射线能谱仪(EDS)分析了涂层的形貌结构及其组成,通过电化学测试研究了涂层/Q235碳钢体系在3.5%Na Cl溶液中的腐蚀电化学行为。结果表明,高分子涂层能有效提高碳钢的耐腐蚀性能,且PE涂层比EP涂层对碳钢的保护性能更好。     

Q235钢焊缝在亚硫酸铵介质中的腐蚀行为

针对Q235钢焊缝在亚硫酸铵介质中腐蚀严重的实际,采用三电极电化学研究法和金相组织分析法研究了J420焊条焊接Q235钢的焊缝在亚硫酸铵介质中的腐蚀行为。研究结果表明,Q235钢用J420焊条焊接后,焊缝的组织特点决定了其耐腐蚀性较差。温度升高、亚硫酸铵溶液浓度增大,均可以促使焊缝的腐蚀速率增大。     

环氧涂层提高Q235碳钢耐蚀性的研究

为改善Q235碳钢的耐蚀性,在其表面涂覆了1种环氧涂层。采用中性盐雾试验(NSS)、湿热试验、盐水全浸试验和电化学交流阻抗谱(EIS)对比了Q235钢涂覆前后的耐蚀性能。结果表明,Q235钢涂覆后在盐水中的平均腐蚀速率仅有38.8 mg/(m2·h),下降了86.3%以上,低频阻抗数值增加了3个多数量级,耐蚀能力显著提高。     

原油储罐底部油泥对Q235B碳钢腐蚀行为的影响

通过热重分析、电化学分析、组织结构分析等研究了油泥在原油沉积水中对Q235B碳钢腐蚀行为的影响。结果表明,油泥覆盖的Q235B碳钢在模拟沉积水中浸泡的前21 d内腐蚀速率逐渐升高,腐蚀形式以点蚀为主。浸泡21 d后Q235B碳钢的腐蚀速率下降,腐蚀形态由局部腐蚀为主转变成全面腐蚀。在腐蚀的起始阶段,油泥中含有的硫酸盐还原菌(SRB)能够诱导碳钢发生局部腐蚀。随着浸泡时间延长,腐蚀产物和油泥沉积层附着在金属表面,抑制了腐蚀反应的继续进行。     

不同材质在蒸氨系统腐蚀行为的研究

通过调查蒸氨系统材料的腐蚀情况,分析腐蚀性介质含量、腐蚀产物及形貌等了解各腐蚀性介质在系统中的分布情况,初步选定碳钢Q235、20#钢、16MnR、普通不锈钢、304不锈钢和316L不锈钢6种材质。进行实验室静态挂片试验和溶液中的电化学试验,并借助金相显微分析、X-衍射、光电子能谱仪、扫描电镜、电化学综合测试仪等检测手段对实验结果进行对比、评价,找出耐腐蚀性能较好的3种材质,进行现场挂片试验．研究在蒸氨系统的实际腐蚀行为,评价耐腐蚀性能,为蒸氨系统改造提供依据。     

碳钢贮热水箱的模拟腐蚀试验及涂层耐蚀性能研究

碳钢贮热水箱长期在30～80°C温变的热水环境中工作,易受到热水及水中杂质的腐蚀。研究了不同温度下Q235钢在自来水及含100μg/mLNaCl的自来水中的腐蚀速率。对裸钢及其涂覆相同厚度的不同涂层──酚醛环氧(自制)、钛纳米聚合物和改性聚乙烯后在70°C自来水中的极化曲线进行了比较。采用动电位扫描极化曲线测量和电化学交流阻抗谱法(EIS)分别对涂覆不同涂层的Q235钢进行了耐蚀性能研究。结果表明,3种防腐涂层均具有较佳的抗热水性,耐蚀能力较强,适宜对Q235钢贮热水箱进行防护。     

铁细菌对供水系统金属管材腐蚀行为的影响

铁细菌(iron bacteria, IB)是供水系统中影响金属管材腐蚀的主要微生物。从实际运行供水管道中提取IB,选用304不锈钢、316不锈钢、Q235碳钢和球墨铸铁,采用电化学分析、表面分析等方法,研究IB对上述管材腐蚀行为的影响。结果表明,IB体系中304不锈钢、316不锈钢的腐蚀速率在试验周期内随时间增加逐渐增大,Q235碳钢、球墨铸铁腐蚀速率则先快速增大后逐渐减小。IB体系中304不锈钢、316不锈钢表面产生较薄腐蚀层,球墨铸铁表面存在大量腐蚀产物和IB,Q235碳钢表面发现少量产物。球墨铸铁和Q235碳钢的腐蚀产物主要为磁铁矿、针铁矿、镁铁氧化物,但这些腐蚀产物在304不锈钢、316不锈钢表面未检出。IB对4种管材的腐蚀作用排序为：球墨铸铁>Q235碳钢>304不锈钢>316不锈钢。     

不同浓度TH-628缓蚀剂对20#钢焊缝腐蚀影响

采用电化学噪声测试技术和电化学极化技术,研究了不同浓度TH-628缓蚀剂对20#钢及含有焊缝的20#钢腐蚀快慢的影响。试验结果表明:TH-628缓蚀剂能明显减缓循环水对20#钢和含有焊缝20#钢的腐蚀,随着TH-628缓蚀剂浓度的增加,腐蚀速率随之下降。含焊缝试件腐蚀减缓速度低于不含焊缝试件,焊缝部位的腐蚀是整个设备的薄弱环节,建立在线腐蚀监测系统重点应考虑焊缝部位。     

模拟工业大气环境中碳钢和耐候钢的腐蚀行为研究

用Na HSO3溶液进行模拟工业大气环境的加速腐蚀试验,研究Q235钢和耐候钢在加速腐蚀试验中的腐蚀情况,通过腐蚀质量损失法对试样的腐蚀速率进行分析,得到Q235钢的腐蚀速率高于耐候钢。采用X-射线衍射对腐蚀产物的成分进行分析,Q235钢和耐候钢的主要腐蚀产物均为Fe2O3、Fe SO4、α-Fe OOH和γ-Fe OOH。电化学测试对腐蚀过程进行分析,耐候钢的耐蚀性更好。表明Q235钢和耐候钢的锈层都有明显的保护作用,耐候钢的耐腐蚀性优于Q235钢。     

温度和Cl-对Q235钢在MDEA/CO2体系中腐蚀行为的影响

通过浸泡腐蚀试验和电化学测量研究了温度和Cl-质量浓度对Q235钢在CO2饱和的20％(质量分数)N-甲基二乙醇胺溶液(MDEA/CO2)中腐蚀行为的影响.结果表明,温度和Cl-质量浓度对Q235钢在MDEA/CO2体系中腐蚀行为的影响是交互的.Cl-质量浓度为1 g/L和10 g/L时,Q235钢的腐蚀速率随温度升高而增大;Cl-质量浓度为15 g/L时,Q235钢的腐蚀速率随温度升高呈先增后减的变化趋势.     

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。