氧化铋掺杂对铌酸钾钠无铅压电陶瓷性能的影响

用传统固相反应法制备了结构致密的铌酸铋钾钠[(Na0.5K0.5)1-3xBixNbO3,0≤x≤0.05]无铅压电陶瓷,研究了掺杂氧化铋(Bi2O3)对铌酸钾钠(Na0.5K0.5)NbO3(NKN)晶体结构和压电性能的影响.结果表明:当Bi2O3含量x＜0.02时,能得到具有纯钙钛矿结构的(Na05K0.5)1.3xBixNbO3陶瓷.最佳烧结温度随Bi2O3含量的增加而升高,与纯铌酸钾钠陶瓷相比,样品密度显著提高.Bi2O3掺杂量对铌酸钾钠的压电性能有很大影响,其压电常数(d33),机电耦合系数(kp,kt)随Bi2O3含量的增加先升高而后降低,并在x=0.01时达到最大值,机械品质因数(Qm)有明显提高.实验表明:当x=0.01时,(Na0.5K0.5)1-3BixNbO3无铅压电陶瓷的密度达4.42g/cm3,表现出优异的压电性能:d33=154×10-6C/N,kp=45%,kt=46%,介电损耗tanδ=3.5%,相对介电常数ε=598,Qm=138.     

制备工艺对0.95(K_(0.5)Na_(0.5))NbO_3-0.05CaZrO_3基无铅陶瓷压电性能的影响

采用传统陶瓷工艺制备了0.95(K0.5Na0.5)NbO3-0.05CaZrO3无铅压电陶瓷。研究了烧结温度和极化工艺对陶瓷压电性能的影响。结果表明:随着烧结温度的提高,0.95(K0.5Na0.5)NbO3-0.05CaZrO3陶瓷的体积密度增大,在1170℃时达到最大值,同时d33和kp,在此温度也分别达到他们的最大值210pC/N和0.40。极化工艺对0.95(K0.5Na0.5)NbO3-0.05CaZrO3陶瓷的压电性能有明显的影响,0.95(K0.5Na0.5)NbO3-0.05CaZrO3陶瓷的最佳极化温度是70℃,最佳极化电场是4kV/mm。     

掺杂对(Na_(1/2)K_(1/2))NbO_3-CaTiO_3无铅陶瓷烧结温度和电学性能的影响

通过传统固相反应法、利用两步合成工艺,在常压、960～1160℃烧结制备0.95(Na1/2K1/2)NbO3-0.05CaTiO3(0.95NKN-0.05CT)及WO3、CuO掺杂0.95NKN-0.05CT无铅压电陶瓷。X射线衍射分析表明:960℃和1020℃烧结制备的掺杂前后的0.95NKN-0.05CT陶瓷均为纯钙钛矿结构。随着CuO掺杂量的增加及烧结温度的升高,CuO掺杂0.95NKN-0.05CT陶瓷中出现杂相,并伴随着压电性能的下降。添加第二组元CaTiO3和氧化物掺杂可增加(Na1/2K1/2)NbO3(NKN)陶瓷的致密度,同时烧成陶瓷的介电、铁电和压电性能也有明显改善。摩尔分数分别为1%和2%CuO掺杂0.95NKN-0.05CT陶瓷的压电常数分别达到165pC/N和140pC/N。     

BiFeO_3-K_(0.5)Na_(0.5)NbO_3无铅压电陶瓷的烧结工艺

采用传统固相烧结法制备性能良好的铁酸铋(BiFeO3,BF)掺杂的铌酸钾钠(K0.5Na0.5NbO3,KNN)压电陶瓷(BF-KNN),着重研究BF摩尔(下同)掺量对KNN结构与压电性能的影响规律以及BF-KNN陶瓷的烧结工艺。结果表明:适量BF有利于提高BF-KNN的压电性能,当BF掺量≥1%后,压电性能急剧降低。与仅烧结一次的样品相比,二次烧结BF-KNN陶瓷形成更加稳定的正交晶系钙钛矿结构,陶瓷组织致密,压电性能大幅度提高,压电常数(d33)、平面机电耦合系数(kp)与机械品质因数(Qm)分别达134pC/N、46%和364,但介电性能明显降低,相对介电常数(εr)从退火前的554降至388。一次、二次烧结样品的体积密度分别为4.12g/cm3和4.36g/cm3,相对密度分别为91.35%和96.67%。在温度低于490℃、频率为100kHz时,二次烧结样品的介电损耗tanδ5%,其Curie温度高达420℃。     

铋掺杂对铌酸钾钠无铅压电陶瓷结构和性能的影响

用常压烧结法制备铋掺杂铌酸钾钠无铅压电陶瓷(K0.5Na0.5)1-3xBixNbO3(KNBN)。研究不同铋掺杂量对KNN陶瓷结构、形貌、致密度及电学性能的影响。结果表明:在1 120℃烧结的含铋量为1%(摩尔分数)的陶瓷表现出最好的铁电和压电性能及较好的介电性能,即压电常数最大121pC/N,P-E回线形状达到饱和,且剩余极化为12.67μC/cm2,矫顽场Ec为13.58kV/cm,介电常数为575,损耗为5.82%(频率为1kHz)。陶瓷样品在131℃从正交结构转变到四方结构,Curie温度为400℃。     

(K_(0.44)Na_(0.52)Li_(0.04))(Nb_(0.86)Ta_(0.10)Sb_(0.04))O_3陶瓷的压电性能

采用传统固相法制备Li、Ta和Sb共同掺杂铌酸钾钠(KNN)的(K0.44Na0.52Li0.04)(Nb0.86Ta0.10Sb0.04)O3(KNLNTS)无铅压电陶瓷。研究不同烧结温度对该陶瓷的结构、形貌、致密度以及电学性能的影响。结果表明:不同温度下烧结的陶瓷样品均为钙钛矿相结构;在1 050~1 150℃之间烧结均可获得性能良好的陶瓷样品;1 050℃烧结的样品表现出最佳的综合电学性能,即相对介电常数和压电系数均较大,分别为1 120pC/N和193pC/N,介电损耗较小为2.55%,机械品质因子较大为85,密度较大为4.65g/cm3,且该样品具有饱和的电滞回线。随着烧结温度的升高,陶瓷样品电学性能下降和晶粒增大均与样品中存在着碱金属离子挥发有关。KNLNTS陶瓷样品的Curie温度由不掺杂的KNN陶瓷样品的420℃下降为301℃。     

低温烧结PZT-O.5%PbO·WO3压电陶瓷

以固态氧化物为原料,采用一次合成工艺制备锆钛酸铅(lead zirconate titanate,PZT)-0.5%PbO·WO3压电陶瓷,研究摩尔比n(Zr)/n(Ti)、烧结温度对陶瓷性能的影响.结果发现:合成温度900℃保温2 h可以得到钙钛矿结构压电陶瓷.n(Zr)/n(Ti)=1.08时,烧结温度为1 100℃保温2 h,压电陶瓷的综合性能在准同型相界处达最佳:介电常数εT33/ε0=1 593,介电损耗tgδ=0.019,压电系数d33=363.5×10-6C/N,机电耦合系数Kp=0.596,机械品质因数Qm=8 8.4.     

含有压电陶瓷颗粒的结构陶瓷基复合材料的制备与性能

为了研究压电陶瓷颗粒对结构陶瓷力学性能的影响,把不同的压电陶瓷 颗粒加入到Al2O3结构陶瓷,发现LiTaO3与Al2O3在烧结时能稳定共存,烧结温度高于1400℃时,LiTaO3发生化,冷却后呈网状分布在AlO3基体晶界;低于1400℃烧结,LiTaO3颗粒弥散分布在Al2O3基体中,采用200MPa冷等静压成型,1300℃（保温3小时）空气气氛下无压烧结,最后于1300℃,150MPa（保温保压1h)氩气气氛下热等静压制备了LiTaO3/Al2O3陶瓷复合材料,对其显微结构与力学性能进行了研究,结果表明,LiTaO3体积分数为5％的陶瓷复合材料具有最高的抗弯强度与断裂韧性值,分别达到438．7MPa和5．4MPa.m^1/2,电畴运动和／或压电 应引起的能量耗散是一种新的陶瓷强韧化机制。     

低温烧结PZT–0.5%PbO·WO_3压电陶瓷

以固态氧化物为原料,采用一次合成工艺制备锆钛酸铅(leadzirconatetitanate,PZT)–0.5%PbOWO3压电陶瓷,研究摩尔比n(Zr)/n(Ti)、烧结温度对陶瓷性能的影响。结果发现:合成温度900℃保温2h可以得到钙钛矿结构压电陶瓷。n(Zr)/n(Ti)=1.08时,烧结温度为1100℃保温2h,压电陶瓷的综合性能在准同型相界处达最佳:介电常数ε3T3/ε0=1593,介电损耗tg?=0.019,压电系数d33=363.5×10-6C/N,机电耦合系数Kp=0.596,机械品质因数Qm=88.4。     

碱土金属钛酸盐掺杂(K_(0.5)Na_(0.5))NbO_3陶瓷的烧结特性与电学性能

采用标准电子陶瓷制备工艺制备了Na_(0.5)K_(0.5)NbO_3陶瓷和高组分碱土金属钛酸盐0.06AETiO_3(AE=Mg、Ca、Sr和Ba)掺杂(K_(0.5)Na_(0.5))NbO_3陶瓷,研究了不同的碱土金属离子对NKN陶瓷的烧结特性和电学性能的影响。研究表明,1130℃烧结成瓷的NKN-CaT和NKN-SrT陶瓷获得了高的相对密度(96%);室温下,XRD图谱显示,NKN-CaT、NKN-SrT和NKN-BaT陶瓷均为四方钙钛矿结构;介电温谱显示NKN-CaT、NKN-SrT和NKN-BaT陶瓷的正交-四方相变温度T_(o-t)移到了室温以下;室温下NKN-CaT、NKN-SrT陶瓷表现出了明显的"软"性掺杂的性能,并获得了高的压电系数d_(33)(171 pC/N和135 pC/N)与机电耦合系数k_p(0.275和0.240)。     

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.     

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.     

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。     

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.     

Inorganic/organic nanocomposite coatings: The next step in coating performance

Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Some Large Wood-Boring Beetles in Southeastern USA

Ethanol and α-pinene were tested as attractants for large wood-boring pine beetles in Alabama, Florida, Georgia, North Carolina, and South Carolina in 2002–2004. Multiple-funnel traps baited with (−)-α-pinene (released at about 2 g/d at 25–28°C) were attractive to the following Cerambycidae: Acanthocinus nodosus, A. obsoletus, Arhopalus rusticus nubilus, Asemum striatum, Monochamus titillator, Prionus pocularis, Xylotrechus integer, and X. sagittatus sagittatus. Buprestis lineata (Buprestidae), Alaus myops (Elateridae), and Hylobius pales and Pachylobius picivorus (Curculionidae) were also attracted to traps baited with (−)-α-pinene. In many locations, ethanol synergized attraction of the cerambycids Acanthocinus nodosus, A. obsoletus, Arhopalus r. nubilus, Monochamus titillator, and Xylotrechus s. sagittatus (but not Asemum striatum, Prionus pocularis, or Xylotrechus integer) to traps baited with (−)-α-pinene. Similarly, attraction of Alaus myops, Hylobius pales, and Pachylobius picivorus (but not Buprestis lineata) to traps baited with (−)-α-pinene was synergized by ethanol. These results provide support for the use of traps baited with ethanol and (−)-α-pinene to detect and monitor common large wood-boring beetles from the southeastern region of the USA at ports-of-entry in other countries, as well as forested areas in the USA.