高温氮化反应合成Ca-α-SiAlON

以Si粉、Al粉、Al2O3粉(α型和ρ型)和CaCO3为主要原料,采用高温氮化方法合成了Ca-αSiAlON,并对氮化后的试样进行XRD、SEM以及EDS分析,计算出了各试样中Ca-αSiAlON的相对含量。研究了氮化温度(1500℃和1550℃),保温时间(8h、12h和20h),CaCO3用量(理论用量、过量10%、过量20%),添加剂种类(Y2O3、TiO2、Fe2O3)及加入量(2%、3%、4%),αSi3N4晶种加入量(0、1%、3%、5%),Al2O3种类(α型和ρ型),Si粉和Al粉的用量(理论用量、过量10%)等工艺因素对Ca-αSiAlON合成量的影响。结果表明:(1)在1550℃氮化反应12h得到的合成产物中Ca-αSiAlON的相对含量最高,可达72.5%,其他物相为βSiAlON;(2)CaCO3加入量增多能够显著提高产物中Ca-αSiAlON的相对含量;(3)添加剂Y2O3、TiO2、Fe2O3均可促进Ca-αSiAlON的合成,其中Y2O3的促进作用最明显,TiO2次之;(4)αSi3N4晶种的引入能够显著提高Ca-αSiAlON的合成量;(5)Si粉和Al粉的量以及Al2O3种类对Ca-αSiAlON的氮化合成影响不明显;(6)SEM分析结果表明,合成的Ca-αSiAlON发育成柱状晶,长径比在3～10之间。     

碳热还原氮化粉煤灰的研究

以粉煤灰加入炭黑为主要原料,在氮气气氛下对粉煤灰进行了碳热还原氮化研究.研究了碳加入量、合成反应温度、保温时间和Fe2O3含量等因素对生成物物相的影响.实验结果表明:选用理论加入碳含量的样品,在反应温度为1350℃、保温9h条件下,产物中含有较多β-Sialon相;而且经磁选除铁后的粉煤灰较未除铁粉煤灰在反应温度为1400℃、保温9h条件下,碳化还原氮化产物中15R相含量明显增多.     

β-SiAlON加入量对刚玉基超低水泥浇注料流变性的影响

以矾土基电熔刚玉为骨料,电熔白刚玉粉、αAl2O3微粉、SiO2微粉、纯铝酸钙水泥和矾土基β-SiAlON为基质,固定骨料和基质的质量比为68∶32,水泥加入量(质量分数,下同)2%,SiO2微粉和Al2O3微粉总加入量为8%,分别用0、4%、6%、8%和10%的β-SiAlON替代刚玉细粉,加水混匀后制成刚玉基超低水泥浇注料。用浇注料流变仪研究了βSiAlON加入量对此浇注料流变性(包括扭矩、流动阻力和粘度)的影响,结果表明:随βSiAlON加入量的增加,在变化的剪切速率下,刚玉基浇注料的扭矩、剪切粘度和流动阻力增加,流变性变差,自流浇注所需加水量增加,流动性降低。综合考虑,合适的β-SiAlON加入量为4%～6%。     

铝硅混合凝胶对刚玉-莫来石制品性能的影响

按莫来石骨料占65%(质量分数),刚玉和黏土组成的混合粉占35%(质量分数)配料,分别外加占原料总质量4%的水、硅溶胶、铝硅混合凝胶作结合剂,研究了结合剂种类对刚玉-莫来石材料经1 100、1 400和1 600℃分别保温3 h烧后的性能及显微结构的影响,并在此基础上研究了铝硅混合凝胶加入量(分别为1%、2%、3%、4%)及配比(m(Al2O3):m(SiO2)分别为8:2、7:3、4:6)对刚玉-莫来石制品常温性能的影响.结果表明:以铝硅混合凝胶为结合剂的刚玉-莫来石试样,经1 400、1 600℃烧后的常温、高温抗折强度和抗热震性均比仅加硅溶胶或水的好,但显气孔率偏大;当铝硅混合凝胶加入量为2%且m(Al2O3):m(SiO2)=7:3时,烧后试样的常温强度最高.     

SiAlON对MgO基浇注料高温性能的影响

以电熔镁砂为骨料,以电熔镁砂细粉、电熔白刚玉、矾土基β-SiAlON、α-Al2O3微粉和SiO2微粉为基质,固定电熔镁砂骨料与基质的质量比,并固定基质中各成分的质量分数,基质中用SiAlON逐步取代刚玉细粉,试样经 1600℃ 3h烧成后,考察SiAlON加入量(0、2. 5%、5%、7. 5%、10% )对浇注料热震稳定性、高温抗折强度(1400℃)等性能的影响,并对试样进行扫描电镜和能谱分析。结果表明:由于SiAlON的引入,在MgO基浇注料基质中起到了强化增韧作用,提高了浇注料的抗热震性能和高温抗折强度。     

钾长石矿差异化利用技术研究

本研究利用钾长石矿物嵌布不均匀的自然特性,以差异化利用为原则,研发了不同等级钾长石矿的合理开发工艺流程。以河南某钾长石矿为研究对象,针对高品位钾长石矿采用磨矿—分级—湿式强磁选除铁工艺,在原矿Fe2O3质量分数为0.247%时,得到产率为76.68%、Fe2O3质量分数为0.078%的釉料级钾长石微粉;针对中品位钾长石矿采用磨矿—脱泥—浮选—强磁选除铁工艺流程,在无氟和弱酸性条件下,实现了长石石英的有效分离,在原矿K2O品位为8.27%、Fe2O3质量分数为0.36%时,获得产率为51.02%、K2O品位为11.08%、Fe2O3质量分数为0.091%的高品质钾长石精矿;针对低品位钾长石矿采用磨矿—脱泥—湿式强磁选除铁工艺,在原矿K2O品位为7.03%、Fe2O3质量分数为0.78%时,得到产率为72.73%、Fe2O3质量分数为0.0756%的低档陶瓷配方钾长石精矿。     

催化剂对以硅溶胶为硅源合成碳化硅晶须的影响

以硅溶胶和炭黑为原料,金属硅、三氧化二铁和硅铁合金为催化剂,采用碳热还原法合成碳化硅晶须,通过XRD及SEM对合成产物的物相及形貌进行分析,探讨了合成温度、催化剂种类、催化剂加入量对合成碳化硅晶须的影响.结果表明:在原料中加入催化剂,合成碳化硅晶须的最佳温度为1550℃;以Si-Fe合金为催化剂合成碳化硅晶须的效果明显好于以Fe2O3和金属硅为催化剂合成效果;Si-Fe合金加入量(占SiO2质量分数)为1％时,晶须生成率高,成直线形,长度10 ～ 50μm,直径0.1 ～0.3 μm.     

配碳量对锆英石和氧化铝碳热还原氮化合成ZrN-SiAlON的影响

为了降低合成成本,以低能耗、低成本的天然锆英石、工业氧化铝和焦炭为原料,采用碳热还原氮化法合成了ZrN-SiAlON复相材料。根据反应方程式3Al2O3+6ZrSiO4+27C+8N 26ZrN+2Si3Al3O3N5+27CO设计锆英石和工业氧化铝的原料配比,改变还原剂焦炭的配入质量分数(分别为理论用量、过量5%、过量10%、过量20%),经球磨混合、成型、干燥后,在流动氮气中分别于1 500、1 550、1 600℃保温4 h合成,自然冷却后分析合成产物的相组成和显微结构。结果表明:1)在合成温度为1 500℃时,配碳量的增加有助于ZrN的生成;2)在合成温度为1 550℃时,配炭量过量20%的试样中有15R型的多型体SiAlON(即SiAl4O2N4)生成;3)在合成温度为1 600℃时,配碳量为理论量和过量5%的试样中的多型体SiAlON为15R型,而配碳过量10%和20%的试样中的多型体SiAlON则主要为12H型(即SiAl5O2N5)。     

反应烧结合成O'-SiAlON-BN复合材料的工艺研究

以微米级αSi3N4、SiO2、Al2O3和hBN为原料,通过反应烧结法合成了O’SiAlON-BN复合材料(Si2-zAlzO1 zN2-z的z=0.3)。首先在n(SiO2)/n(αSi3N4)=1的理论配比,1700℃保温2h的条件下对比研究了Y2O3 TiO2和Y2O3 B2O3两种混合烧结助剂对该复合材料的助烧效果。结果表明:Y2O3 TiO2作为烧结助剂比Y2O3 B2O3有更好的促进烧结作用,且复合材料的相对密度随着BN(分别为10%,20%和30%)的增加而降低;XRD分析发现,αSi3N4、SiO2原料在理论配比的情况下,会导致βSi3N4相剩余,为了得到O’SiAlON和BN相含量高的复合材料,需要加入过量的SiO2。根据此研究结果,在以Y2O3 TiO2作烧结剂,BN加入量为10%的条件下,通过4因素3水平(因素水平如下:A———n(SiO2)/n(αSi3N4),取1.05、1.1、1.2;B———烧结助剂加入量,取2%、4%、6%;C———烧成温度,取1600℃、1650℃、1700℃;D———保温时间,取1h、2h、3h)的正交试验确定了影响O’SiAlON-BN复合材料烧结性能的主要因素依次为烧成温度、保温时间、烧结助剂加入量、n(SiO2)/n(αSi3N4),合成的复合材料相对密度最高的工艺参数组合为A3B3C3D3;利用统计模式识别方法对合成O’SiAlON-BN复合材料的工艺条件参数进行了优化,得到的优化区为:Y>1024X2-230.400X 11.088(其中,X=0.9999A-0.0006C-0.0163D,Y=0.0163A 0.0009B-0.0014C 0.9999D),在此优化区内,复合材料中全部为O’SiAlON和BN相,无残留βSi3N4相。     

高铝矾土-硅粉氮化合成SiAlON的过程研究

分别以w(Al2O3)为68.08%和45.56%的两种高铝矾土及硅粉为原料,按合成SiAlON的理论配比配料(Si粉过量5%),成型后在流动N2(流量为0.06~0.1m3.h-1)中进行热重分析,同时测定试样在不同温度(900~1500℃)保温6h后的质量变化,并分析氮化后试样的物相变化,从而探讨该试样的氮化过程及其机理。结果表明,高铝矾土-硅粉试样在流动N2中的氮化反应过程可大致分为3个阶段:1)Si粉氮化阶段(900~1200℃),Si粉氮化生成Si3N4和Si2N2O;2)SiAlON形成阶段(1300~1400℃),生成O’-SiAlON和β-SiAlON;3)β-SiAlON的生长发育阶段(1450~1500℃),部分O’-SiAlON转化为β-SiAlON,Al2O3在β-SiAlON中的固溶度增加。     

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。