提高镁碳质出钢口管砖使用寿命的途径

将粒度为3~1mm和≤1mm、w(MgO)=98%的电熔镁砂,w(C)=97%的鳞片石墨以及金属铝粉(≤0.088mm、w(Al)>97%),硅粉(≤0.088mm、w(Si)>98%),碳化硅粉(≤0.088mm、w(SiC)>97%)和碳化硼粉(≤0.043mm)等抗氧化剂按一定比例混练成型为110mm×350mm试样,再将试样加热至1400℃保温2h后研究了复合抗氧化剂的效果和机理;然后通过改变配料中的颗粒级配工艺,研究了材料常温和中温处理后的性能以及材料的显微结构。结果表明:采用适当的复合抗氧化剂Al-Si的效果最好;将传统的3级配料优化后,按照颗粒级配方程设计的4级配料方法制备的试样,可以明显提高材料的中温性能,材料致密程度也明显改善。在此研究的基础上,实际制备的镁碳质出钢口管砖的实际试用结果比以前材料的寿命提高了50%左右。     

微孔富镁尖晶石对低碳MgO-C材料性能的影响

分别以微孔富镁尖晶石(5~3和3~1 mm)和电熔镁砂(5~3和3~1 mm)为粗骨料,以<1 mm的电熔镁砂为细骨料,以镁砂粉(≤0.088 mm)、鳞片石墨粉(≤0.088 mm)、金属铝粉(≤0.074 mm)为细粉,以酚醛树脂为结合剂,制备了w(C)=6%的两种低碳MgO-C材料,经220和1 500℃(埋焦炭)热处理后,测定其显气孔率、常温耐压强度、常温抗折强度、加热永久线变化率、抗热震性和抗渣性。结果表明:1)用微孔富镁尖晶石骨料取代普通低碳MgO-C材料中的部分镁砂骨料后,经220和1 500℃热处理后试样的显气孔率均比普通低碳MgO-C试样的大,体积密度均比普通低碳MgO-C试样的小;220℃固化后试样的强度比普通低碳MgO-C试样的小,但1 500℃热处理后试样的强度比普通低碳MgO-C试样的大;1 500℃热处理后试样的加热永久线变化率比普通低碳MgO-C试样的小。2)使用微孔富镁尖晶石骨料代替电熔镁砂骨料能有效提高低碳MgO-C材料的抗热震性,但对低碳MgO-C材料的抗侵蚀性不利。     

不同添加剂加入量对Al_2O_3-SiC-C砖性能影响

为进一步提高Al_2O_3-SiC-C砖的性能,以≤5mm的均化矾土料、≤5mm的板状刚玉、≤1mm的碳化硅、0.044mm的α-Al_2O_3微粉和≤0.154mm的石墨等为原料,以酚醛树脂为结合剂制备了Al_2O_3-SiC-C不烧砖。研究了电熔镁砂粉、叶蜡石粉或红柱石粉的加入量(w)皆分别为1%、2%和3%时对试样各项性能的影响,并采用国标对220℃保温24h后试样的各项性能进行检测。结果表明:在Al_2O_3-SiC-C砖中添加少量电熔镁砂粉、红柱石粉、叶蜡石粉可提高试样的高温抗折强度和抗热震性能,加入1%(w)电熔镁砂粉的试样高温抗折强度最大,加入1%(w)红柱石粉的试样抗热震性最好;添加1%(w)电熔镁砂粉可减少熔渣对均化矾土的侵蚀,明显提高试样的抗渣侵蚀性能。综合考虑,加入1%(w)电熔镁砂粉的试样性能最佳。     

防氧化剂TiN和Al对MgO-C砖性能的影响

以3~1mm、<1mm、<0.088mm的电熔镁砂和<0.15mm的鳞片石墨为原料,热固性酚醛树脂为结合剂,分别加入0.5%、1%、2%、4%的含碳TiN或2%的Al粉为防氧化剂,制备了镁碳砖试样,并与无防氧化剂的试样对比进行抗氧化性和抗渣侵蚀试验。结果表明:添加Al粉试样的抗氧化性能最好,TiN的次之,未加防氧化剂的最差;添加TiN试样的抗渣性能最好,无防氧化剂的次之,添加Al粉的最差。镁碳砖中引入适量TiN后明显提高抗渣侵蚀性能的原因是:TiN氧化生成TiO2时产生的体积膨胀堵塞气孔,阻止熔渣侵入;TiO2与渣中的CaO反应生成3CaO·2TiO2,提高渣的粘度。综合各项性能,TiN的最佳加入量为2%。     

添加硼镁矿对镁碳砖高温性能的影响

为研究采用较廉价的天然低品位硼镁矿(高镁低硼)代替价格昂贵的含硼防氧化剂(如B4C、Ca B6、Zr B2等)在镁碳砖中使用的可行性,在以50%(w)的3~1 mm电熔镁砂、20%(w)的≤1 mm电熔镁砂、17%(w)的≤0.088 mm的电熔镁砂、10%(w)的鳞片石墨、3%(w)的酚醛树脂以及外加1%(w)沥青制备的镁碳砖基础上,以Al粉、Ca B6粉和经650℃煅烧的硼镁矿粉为添加剂,分别研究了单独添加3%(w)硼镁矿粉或Al粉或Ca B6粉以及复合添加3%(w)的硼镁矿粉+Al粉或Ca B6粉+Al粉时,对镁碳砖抗氧化性、高温抗折强度和抗渣侵蚀性的影响。结果表明:用硼镁矿替代Ca B6并与Al粉复合加入镁碳砖中,可以获得良好的高温使用性能,当2%(w)硼镁矿与1%(w)Al粉复合添加时,试样的综合高温性能最佳。     

石墨种类对超低碳MgO-CaO-C砖性能的影响

以电熔镁钙砂(粒度为5~3、3~1和≤1 mm)为骨料,电熔镁砂(≤0.074 mm)为基质,分别加入3%(w)的大鳞片石墨(≤0.149 mm)、细鳞片石墨(≤0.044 mm)、微孔化石墨(≤0.074 mm)制备了3种超低碳MgO-CaO-C砖试样,并对比了其高温强度、抗氧化性、抗热震性和抗渣侵蚀性。结果表明:(1)石墨种类对超低碳MgO-CaO-C砖的物理性能影响不大。(2)大鳞片石墨制备的超低碳MgO-CaO-C砖的抗氧化性和抗渣侵蚀性较好,而微孔化石墨制备的试样抗热震性最好;考虑到整体性能,碳源以1.5%(w)大鳞片石墨与1.5%(w)微孔化石墨的复合形式加入最佳。     

SiC结合刚玉材料的抗高炉渣侵蚀性

采用电熔刚玉、Si粉和SiC粉为原料,用酚醛树脂做结合剂,混练成型后于1 450℃埋炭烧成,采用静态坩埚抗渣试验研究了烧后试样对碱度为1.1的高炉渣在1 500℃的抗渣侵蚀性。结果表明:Si与C、CO在高温下原位反应生成纤维状SiC,形成原位SiC结合刚玉材料,该材料具有良好的抗侵蚀性能,渣蚀厚度都在2.6mm以下,其中,加入8%(w)Si粉和5%(w)SiC粉的试样抗渣侵蚀性最好。通过对抗侵蚀后试样的侵蚀层、渗透层和未变层的相组成和显微结构的分析认为:(1)这种复合材料抗渣侵蚀性能良好的主要原因是熔渣难润湿的SiC自身抗渣侵蚀性较好,且原位生成的纤维状SiC穿插在刚玉骨架结构的空隙中,阻挡了熔渣的侵蚀和渗透;(2)熔渣侵蚀材料的过程是SiC先被氧化,然后其氧化产物SiO2与熔渣中的CaO和SiO2以及材料基质中的A l2O3反应生成钙长石低熔相。     

电熔镁砂加入量对Al2O3-SiC-C浇注料性能的影响

以电熔棕刚玉颗粒(粒度为5~3 mm、3~1 mm,≤1 mm)、电熔白刚玉细粉(≤0.088 mm)、SiC颗粒(≤1 mm)和细粉(≤0.088 mm)、电熔镁砂细粉(≤0.088 mm)、活性α-Al2O3微粉、SiO2微粉、Si粉和球状沥青为主要原料,以纯铝酸钙水泥为结合剂,配制成电熔镁砂细粉加入量(质量分数)分别为0、3%、6%、9%、12%的出铁沟用Al2O3-SiC-C浇注料,经振动成型、养护、脱模、110℃24 h烘干后,分别于1 100℃3 h、1 450℃3 h热处理,测定处理后试样的体积密度、显气孔率、烧后线变化率、抗折强度、抗高炉渣侵蚀性和抗氧化性,并分析其物相组成和显微结构。结果表明:随着电熔镁砂加入量的增加,试样的显气孔率提高,体积密度、抗折强度和抗氧化性降低,抗渣性变化不大;1 450℃3 h处理后试样物相主要由3C-SiC、6H-SiC、刚玉、方镁石以及反应生成的尖晶石和莫来石组成,且随着电熔镁砂加入量的增加,尖晶石和莫来石的生成量也增加;在侵蚀面附近,刚玉颗粒边缘生成了厚度约80μm的尖晶石层。     

配料组成对镁碳材料热膨胀性能的影响

由于低碳钢、超低碳钢和不锈钢的冶炼等的需要,低碳镁碳砖得到了较快的发展。低碳镁碳砖的抗剥落性较差,而热膨胀性能是影响镁碳砖抗剥落性的主要因素之一。本工作研究了添加剂种类(铝粉和硅粉)和加入量、石墨加入量、结合剂种类和加入量及电熔镁砂档次对镁碳材料的热膨胀曲线、烧后线变化率和脱碳层厚度等的影响。1试验1.1原料及试样试验用主要原料有:电熔镁砂(w(MgO)=98%)、-198石墨、金属铝粉和硅粉等。按表1的配比配料(其中,5#配方中粒度>1mm的镁砂是用1.3%的树脂涂覆且固化过的,其表面有一层树脂炭化层),在液压机上以250MPa的压力分…     

含铝粉的MgO-SiC材料对钢水的增碳行为

分别以93%或96%的电熔镁砂(3~1mm,≤1mm,≤0.088mm)、4%的碳化硅粉(≤0.088mm)、3%或0的金属铝粉(≤0.088mm)为主要原料,配成含铝粉和不含铝粉的MgO-SiC试样,以热固性酚醛树脂为结合剂,在等静压压力机上以200MPa的压力压制成坩埚,自然养护24h后于230℃保温24h,然后在坩埚中加入5kg超低碳钢,并在钢样表面覆盖120g无碳保护渣,放入感应炉中加热至1600℃至钢水熔化,每隔30min取1份钢样,共取6份,化验钢样中的碳含量,并对试验后试样与钢水的反应层进行显微镜观察和EDAS分析。结果表明:SiC氧化形成的SiO2保护膜以及MgO-CaO-SiO2液相的形成,有利于降低SiC对钢水的增碳作用;金属铝粉的加入减少了SiC的氧化,并且可能对钢水产生脱氧作用,导致SiC向钢中增碳。     

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.     

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.