反应烧结Al203-SiC制品的性能和结构研究

研究了siC和添加剂对Al2O3-siC制品性能的影响.结果表明加入的SiC(10%～15%)能在基质中形成紧密的网络结构;利用添加剂与碳素材料的反应,促进了制品的烧结,从而改善了制品的结构与强度.该结果为制取性能优良的烧成Al2O3-SiC复合材料提供了依据.     

氧化铝基纳米复合陶瓷显微结构的研究

考察了Al2O3-SiC和Al2O3-ZrO2(3Y)-SiC纳米复合陶瓷的断裂方式。由于SiC的加入,材料以穿晶断裂为主。通过透射电镜观察,研究了纳米复合陶瓷中材料SiC颗粒的分布,证明所制备的材料为晶内型纳米复合陶瓷。在Al2O3-ZrO3(3Y)-SiC纳米复合陶瓷中,小的ZrO2颗粒分布于Al2O3晶粒内,大的ZrO2晶粒位于Al2O3晶粒间,ZrO2的分布影响Al2O3晶粒的形状。通过高分辨透射电镜,观察了Al2O3-SiC和Al2O3-ZrO2(3Y)-SiC纳米复合陶瓷中Al2O3/Al2O3,Al2O3/SiC,Al2O3/ZrO2的界面。在两颗晶粒间的晶界几乎没有玻璃相的存在,证明纳米复合材料中晶界得到了加强,有利于力学性能的提高。     

Al_2O_3–SiC复相陶瓷的摩擦磨损特性

用真空热压工艺制备了Al2O3-SiC复相陶瓷.对热压烧结的纯Al2O3以及Al2O3-SiC复相陶瓷进行了摩擦磨损实验,研究了SiC添加量对复 相陶瓷摩擦磨损性能的影响.结果表明:在压力为25 MPa,1635℃热压烧结1h,当SiC的质量含量为5%时,Al2O3-SiC复相陶瓷的耐磨性最佳,虽摩擦系数最大(0.61,Al2O3则为0.46),但磨损率(WR)仪为5×10-4mm3/(N·m).Al2O3-SiC复合材料的磨损机理为脆性断裂引起的磨粒磨损,材料的 WR与断裂韧性(KIc)和Vickers硬度(Hv)的乘积(KIc1/2HV5/8)成反比.     

熔铸AZS回收料对Al2O3-SiC制品性能的影响

采用75%的特级铝矾土熟料(w(Al2O3)>90%)作骨料,15%的冶金碳化硅(w(SiC)=97%)、8%的结合粘土及2%的硅粉作基质粉,成型后于1400℃保温6h烧成,制成混铁炉渣线、出铁口用普通Al2O3-SiC制品,并在此基础上分别用5%、10%和15%的玻璃窑用后的熔铸AZS回收料(≤1mm和≤0.088mm两种粒度)替代等量的矾土熟料制成改性Al2O3-SiC制品,研究了熔铸AZS回收料对制品常温物理性能、抗热震性、抗氧化性以及抗渣侵蚀性的影响。结果表明:熔铸AZS回收料的引入,增大了基质液相的粘度,改善了制品的显微结构,有利于制品抗热震性能的提高,并对高钙渣系具有良好的抗冲刷及抗侵蚀性;综合考虑材料的各种性能,熔铸AZS回收料的加入量以10%为佳。     

鱼雷罐用微气孔高强度Al2O3-SiC砖的研制与应用

以特级矾土(粒度分别为5~3mm、3~1mm、≤1mm、≤0.088mm)、工业SiC(粒度≤1mm)、电熔刚玉(粒度分别为3~1mm和≤0.088mm)和软质黏土粉(粒度≤0.088mm)为原料,按常规生产工艺制备鱼雷罐用烧成Al2O3-SiC砖,研究了粒度组成以及硅微粉、活性氧化铝微粉、蓝晶石微粉和红柱石微粉4种添加剂及其加入量(分别为3%、5%和8%)对Al2O3-SiC砖显气孔率、孔径分布和强度的影响,并在钢厂鱼雷罐上对研制的Al2O3-SiC砖进行了实际使用试验。结果表明:以颗粒紧密堆积理论为基础设计原料的粒度组成,加入合适种类和数量的添加剂,能够生产出强度大,显气孔率低,气孔孔径小且分布窄的Al2O3-SiC砖;研制的Al2O3-SiC砖在钢厂鱼雷罐上使用时具有良好的抗渣侵蚀性和抗铁水冲刷性,粘渣少且易清除,使用寿命比普通Al2O3-SiC-C砖延长34.5%。     

Al2O3-MgAl2O4-SiC—C质耐火浇注料中SiC氧化行为的热力学测定

通过采用Factsage软件进行热力学计算,以探讨MgAl2O4对SiC氧化所起的作用。据热力学推断,在1500％的还原气氛中．没有证据证明尖晶石会直接影响SiC的氧化。而在Al2O3-SiC—C质浇注料中,SiC含量的增加主要与材料中莫来石和碳之间的反应有关。另一方面,Al2O3-MgAl2O4-SiC—C中SiC的产生是材料中液态SiO2和C反应等共同作用的结果。因此,在Al2O3-MgAl2O4-SiC—C质浇注料中较低的SiC含量起因于耐火材料中的相转变。并且,试样在1500％热处理15次依然没有达到稳态条件,这解释了实验和热力学结论之间存在差异的原因。     

SiO2-SiC棚板的性能优化研究

为改善SiO2-SiC棚板的性能,特别是高温性能,以SiC、SiO2为主要原料,黏土粉、Al2O3和CaO微粉为添加剂,羧甲基纤维素为临时结合剂,研究了SiO2加入质量分数(2%、5%、8%、10%),热处理温度(分别为1 380、1 400、1 420、1 440、1 460和1 480℃),添加剂(分别为质量分数0.3%的黏土、Al2O3和CaO微粉)对试样性能的影响,并进行了生产应用。结果表明:1)SiO2加入量提高有利于常温强度的改善,但过高时对高温强度无益,SiO2的最佳加入质量分数为5%。2)提高热处理温度会明显改善SiO2-SiC材料的高温强度,但温度过高时,高温强度反而略有下降,较适宜的热处理温度为1 440℃左右。3)添加黏土、Al2O3和CaO微粉均能使SiO2-SiC材料的常温和高温强度有所提高;添加CaO微粉促进了SiO2的鳞石英化,试样的综合性能最好。4)生产试用结果表明,本研究中最佳试样的使用性能超过其他厂家的。     

SiC数量对Al2O3-SiC—C系浇注料性能的影响

由于Al2O3-SiC—C系浇注料具有较高的抗馒蚀性、抗热震性、热导率及机械强度,因此它得到了广泛的应用。在本文的研究工作中选择了典型的Al2O3-SiC—C系浇注料,并研究了SiC数量对其性能的影响。研究结果表明,当SiC含量提高时,机械强度及抗侵蚀性下降,体积密度降低,开口气孔率增大。     

添加Al2 O3-SiC复相粉体对高炉用炮泥性能的影响研究

本文以棕刚玉、SiC粉、粘土、蓝晶石粉、焦炭粉、沥青粉和Fe-Si3 N4为原料,以焦油为结合剂,分别添加不同质量分数(0、2％、5％、10％、15％和20％)的自制Al2 O3-SiC复相粉体制备得到无水炮泥,并对其体积密度、显气孔率、抗折强度和抗渣性能进行了研究.通过SEM研究了炮泥试样的抗渣侵后产物的显微结构,探讨了不同添加量的Al2 O3-SiC复相粉体对炮泥性能的影响.研究表明:Al2 O3-SiC复相粉体的添加量为10％时,制备的炮泥试样抗折性能最好.在还原气氛下,添加Al2 O3-SiC复相粉体的炮泥具有良好的抗渣性能.     

合成ZrO2-SiC和工业SiC对Al2O3-C质耐火材料性能影响的对比

为了改善Al2O3-C质耐火材料的抗氧化性和抗热震性,向浇注料中分别添加0、2%、4%、6%的SiC或ZrO2-SiC复合粉,以酚醛树脂为结合剂,在200MPa下制备了2组试样,经250℃充分干燥后,于1400℃下埋炭处理2h,分别检测2组试样的抗氧化性和抗热震性,并采用XRD分析氧化后试样的相组成。结果发现,添加剂中SiC的氧化能有效保护试样中的碳,从而能减少试样的质量损失率和氧化面积,提高其抗氧化性能。由于ZrO2的微裂纹增韧及SiC的颗粒增韧作用,使试样的抗热震性能提高。在试验条件下,添加6%ZrO2-SiC复合粉或工业SiC粉时,试样的抗氧化性和抗热震性最佳。     

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。