碳毡处理对碳毡水泥基复合材料力学性能影响

针对传统碳纤维水泥基复合材料存在的纤维分散和界面结合问题,以碳毡作为增强体,实现碳纤维在水泥基体的均匀分散,采用阳极电解氧化法对碳毡进行表面处理,改善纤维与基体的界面结合。然后用水泥浆料浸渍改性后的碳毡,制备碳毡水泥基复合材料。利用万能试验机测试抗弯强度和抗压强度,借助扫描电镜(SEM)分析碳纤维在水泥基体中的分散排列和表面处理后的微观结构。结果表明:碳纤维在基体中分散均匀且排列紧密,占比为12%左右。用阳极氧化法处理碳毡,在10%碳酸铵溶液中2 V电压电解3 min,碳毡改性效果最佳。样品养护7 d的抗弯强度为41 MPa,提升了36.7%,抗压强度为54.3 MPa,提升了8.6%。     

煤储层固井胶结强度性能及改善方法研究

为了解决煤岩表面亲水润湿性差导致的煤层段固井质量差的难题,优选了不同类型的表面活性剂和硅烷偶联剂作为煤体表面润湿改性剂,试验研究了对煤体表面的润湿改性对界面胶结强度等改善效果,并测试评价了对水泥浆流变性能、凝结时间、抗压强度等影响规律。研究结果表明:表面活性剂、硅烷偶联剂均可有效改善煤体表面亲水润湿性;但硅烷偶联剂却不会提高煤层界面胶结强度,其原因是硅烷偶联剂水解产生Si-OH基团吸附在水泥颗粒表面形成包裹层,阻止水泥与水进一步接触,对水泥有较强的缓凝副作用,不利于煤层界面胶结;含醚、硫酸根的阴表面活性剂对水泥没有缓凝副作用,与水泥浆相容性好,能够显著提高煤层界面胶结强度达1.71 MPa,其最优浓度为0.3%。     

超细凹凸棒土机械化学法表面改性及其在LLDPE中的应用

使用搅拌球磨机,利用机械化学法,以硬脂酸作为改性剂,对凹凸棒土进行超细粉碎与表面改性一体化试验,优化工艺条件下改性凹土粉体的活化指数可达0.97,粉体中位径d50为0.64μm.凹土改性前后的红外谱图对比说明硬脂酸与凹土粉体表面产生化学吸附.将改性凹土作为填充剂加入线性低密度聚乙烯(LLDPE),在改性凹土的填充量为6%时,拉伸强度比同填充量的未改性凹土提高28.3%,断裂伸长率提高了12.2%.截面形貌分析图谱表明,改性凹土和基体树脂间建立起牢固的界面结合,边缘过渡平滑,复合材料相关力学性能得到改善.     

碳纤维对粉煤灰地聚物复合材料性能的影响

以高钙粉煤灰为原料、硅酸钠和氢氧化钠为碱激发剂、短切碳纤维为增强材料,制备了碳纤维增强高钙粉煤灰基地质聚合物复合材料,探讨了碳纤维掺量对地聚物复合材料和易性、抗压强度、导电性能及微观形貌的影响。结果表明:随着碳纤维掺量的增加,地聚物复合材料的抗压强度增大,其体积电阻率显著降低,并存在导电渗流现象,阈值介于0.1%~0.2%之间。当碳纤维掺量为0.5%时,28 d龄期试件的抗压强度为45.93 MPa,较未掺碳纤维时提高了34.26%;其体积电阻率仅为5Ω·cm,比未掺时的电阻率降低了2~3个数量级。SEM分析表明,碳纤维与基体界面的黏结性较好,当碳纤维含量超过0.2%时,纤维相互搭接增多,抑制了微裂缝产生和扩展,起到阻裂和增强作用,也为地聚物复合材料导电性能的改善提供了有效导电通路。     

掺无机纤维钢渣胶凝材料的理化特性分析

本文研究了玻纤和矿纤分别掺入钢渣、水泥复合胶凝材料时对胶砂强度和膨胀性的影响。结果表明随着钢渣掺量的提高,各龄期胶砂强度下降;随着纤维掺量的提高,胶砂试件各龄期强度下降,相比纤维掺量为0时,玻纤掺量为0.1%、0.5%时,28 d抗压强度分别提高2.36%、降低10.6%,矿纤掺量为0.1%、0.5%时,28 d抗压强度分别提高7.4%、降低17.2%。沸煮和压蒸试验结果表明,钢渣与水泥配比相同时,玻纤掺量高的试件其压蒸膨胀率低;掺入质量分数0.3%的6 mm玻纤时,试件压蒸膨胀率比纤维掺量为0时降低18.87%;掺入混合玻纤的试件其压蒸膨胀率较单掺时低。SEM显示,随着水化的进行,纤维表面生长C-S-H凝胶以及Ca(OH)2晶体,纤维与基体的粘结程度提高,矿纤与基体的表面粘结程度较玻纤高。     

碳纤维增强镁基复合材料的制备及微观结构分析

采用溶胶-凝胶方法,经过水解、浸渍及干燥烧结,在纤维表面涂覆上一层均匀光亮、无裂纹且厚度适中的二氧化硅涂层.在惰性气体保护下实现三维编织碳纤维增强镁基复合材料的压力浸渗制备.通过SEM和XRD等分析碳纤维表面二氧化硅涂层的形貌、成分及其结构以及复合材料中碳纤维与镁基体界面的微观结构.结果表明,二氧化硅涂层厚度适当的碳纤维与镁合金基体之间通过轻微的界面反应,改善了二者间的润湿性,有效促进了镁合金熔液在三维编织碳纤维中的浸渗过程.     

聚合物水泥浆液-煤体界面过渡区力学性能研究

提出了超前深孔注浆加固技术;利用VAE乳液对水泥基材料进行改性,通过轴拉试验及立方体抗压试验,研究了不同掺量VAE乳液对水泥基材料与煤体界面黏结强度及水泥基材料固结煤体的抗压强度的影响;结合微观电镜扫描,分析了VAE改性水泥基材料结石体与煤体界面过渡区的微观结构特征。研究结果表明:复合浆液水灰比随聚灰比的增大呈现出先降低后增长的趋势,VAE乳液提高了浆液与煤体界面黏结强度及浆液固结煤体试块的抗压强度;掺入VAE乳液,使水泥浆液的孔隙率降低,提高了强效应层结构的密实性;VAE乳液会扩散至普通水泥浆内部形成聚合物薄膜"纽带"结构,改善水泥基材料与煤体界面的组成结构,从而提高了水泥基材料与煤体黏结强度。     

高性能无机-有机复合注浆材料研究

针对千米深井巷道围岩大变形控制难题,提出了支护-改性-卸压"三位一体"协同控制技术,其中要求注浆改性材料具有"高渗透、高强度、高黏结"性能。"高渗透"可以通过减小粒度、增加界面润湿性来实现;"高强度"可以通过优选快速水化矿物,添加纳米增强材料来实现;"高黏结"可以通过添加有机调节剂,增加界面润湿并形成强化学键来实现。本文以超细化的硫铝酸盐水泥熟料、石膏、石灰为主要原料,通过优化配比研发了无机注浆材料,材料粒径D957. 0μm,最佳配比为硫铝酸盐水泥熟料、石膏、石灰质量比5∶4∶1;合成了纳米锂铝类水滑石增强材料,具有锂离子增强和纳米晶核诱导结晶双重协同增强作用,当掺量为无机注浆材料质量的2%时,抗压强度提高145%,达到12. 3 MPa;采用"一锅法"合成了两亲性有机调节剂,掺量为无机注浆材料质量的3%时,可以将水与煤表面接触角从72. 80°减小到19. 23°,并在注浆材料与裂隙表面间形成氢键作用,显著改善界面润湿性,增加界面黏接强度。以无机注浆材料、纳米锂铝类水滑石、有机调节剂按95%,2%,3%的质量百分比混合制备了微纳米注浆材料,材料初、终凝时间分别为8. 0,13. 0 min,2 h抗压强度为10. 2 MPa,煤的黏结强度大于煤自身拉伸断裂强度。微纳米注浆材料在口孜东矿进行了超前注浆应用,可以良好注入10μm开度的裂隙,与裂隙表面结合紧密,锚杆拉拔力由注浆加固前的37 kN提高到注浆后的145 kN。     

掺无机纤维的钢渣胶凝材料的理化特性分析

本文研究了玻纤和矿纤分别掺人钢渣、水泥复合胶凝材料时对胶砂强度和膨胀性的影响.结果表明随着钢渣掺量的提高,各龄期胶砂强度下降;随着纤维掺量的提高,胶砂试件各龄期强度下降,相比纤维掺量为0时,玻纤掺量为0.1％、0.5％时,28 d抗压强度分别提高2.36％、降低10.6％,矿纤掺量为0.1％、0.5％时,28 d抗压强度分别提高7.4％、降低17.2％.沸煮和压蒸试验结果表明,钢渣与水泥配比相同时,玻纤掺量高的试件其压蒸膨胀率低;掺入质量分数0.3％的6 mm玻纤时,试件压蒸膨胀率比纤维掺量为0时降低18.87％;掺入混合玻纤的试件其压蒸膨胀率较单掺时低.SEM显示,随着水化的进行,纤维表面生长C-S-H凝胶以及Ca(OH)2晶体,纤维与基体的粘结程度提高,矿纤与基体的表面粘结程度较玻纤高.     

改性生土砌块配合比试验研究

通过单因素试验对改性生土的工程特性进行试验研究,从而确定草筋、粉煤灰、水泥、生石灰的合理取值区间。利用正交试验方法考察各因素对改性生土抗压强度、抗折强度的影响,并对试验结果进行了极差、方差和因素指标分析。结果表明,各因素对改性生土砌块28 d抗压强度的影响顺序为:水泥C草筋A粉煤灰B生石灰D。各因素对改性生土砌块28 d抗折强度的影响顺序为:草筋A水泥C生石灰D粉煤灰B。综合分析各因素对改性生土砌块抗压强度、抗折强度的影响,最终确定改性生土砌块的最优配合比。     

Market and recycling of NiMH battery

<正>Market status and future trend of NiMH battery1.Global market of small NiMH battery Global market size of small NiMH batteries declined year on year since 2011.The trend will continue to 2018,at the rate of 5%to 10%annually.Demand for small NiMH batteries will be stable gradually.Many electrical apparatuses are powered by the built-in lithium battery today,which is the main reason for the shrunk market of small NiMH batteries.But,for some products,small NiMH     

China rare earth market review

正September 1-10,2014 Affected by the National Day holiday,rare earth transaction was stagnant and the market showed a weak steady state.As there was no good news for downstream market,some products with flat demand would likely rally slightly for some time to     

Current situation and future trend of China rare earth luminescent material industry

<正>Rare earth luminescent material is one of the most important application sectors of rare earths.China enjoys the exceptional advantage to develop rare earth luminescent material for its abundant rare earth resources.After several decades'endeavor,China's rare earth luminescent material industry,headed by rare earth phosphor for lamp and LED and high efficient rare earth energy-saving light source,has been gradually developed into a scale industry.China has become a major production base of rare earth phosphor for lamps and rare earth     

China rare earth market review

正June 1~10,2014Rare earth market remained weak.Quoted price of rare earth products was similar to that in May.There was no sign of recovery in downstream market.The market of NdFeB magnetic materials and phosphor was depressed.Catalyst,polishing powder and ceramic industries remained inactive.Demand from downstream industry was soft.Consumers purchased on their needs.Suppliers had strong intention to sell.Prices of rare earth products     

2014 second batch of rare earth quota released

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Annual Report analysis of Chinese rare earth-related listed companies in 2013

<正>Chinese rare earth-related listed companies have published their 2013 annual reports.It can be understood from their reports that production and operation activities of Chinese rare earth-related companies were still heavily affected by macro economy and industrial policies.They basically followed the steps of national economy.In 2013,world economy recovered slowly but the economy     

Market opportunities and challenges for rare earth polishing powder

正1.Status of rare earth polishing powder Rare earth polishing powder with high content of cerium oxide began to replace iron oxide for glass polishing and became one of the key materials in glass polishing process since 1940.Compared with traditional iron oxide,rare earth polishing powder has many advantages,such as fast polishing rate,high polishing quality and long service life.It can achieve good surface quality and improve operation conditions.For example,in lens polishing,the polishing work that cerium     

Baotou Research Institute of Rare Earths developed a new RE alloy preparation technology

正Pyrometallurgy Laboratory of Baotou Research Institute of Rare Earths had independently developed a new preparation technology of rare earth alloy for NdFeB.The alloy can remarkably enhance the coercivity of NdFeB magnet but also evidently reduce the production cost of the magnet.The new master alloy was prepared in the kA pilot-scale electrolytic cell by the independent technology.The rare earth master alloy can be used as the raw material for NdFeB.Compared     

China rare earth market review

正November 21~30,2014Due to weak demand from downstream industries,transactions of rare earth in Chinese domestic market were inactive.It was difficult to sell any rare earth products except for dysprosium oxide and terbium oxide.Suppliers lost confidence in recent market.Demand for rare earth products was soft.Consumers continued to take a wait-and-see attitude.Rare earth export market remained slow.     

Galaxy Magnets achieved the net profit of 34.02 million yuan in the first six months of 2014

正Galaxy Magnet announced its financial results for the first half of 2014 on August 14.For the first six months ended on 30 June 2014,Galaxy Magnet achieved operation income of RMB 182.3 million,up8.40% over the same period of 2013,and the net profit attributable to the shareholders of the listed company of 34.02 million yuan,increasing 35.49% over the same period of last year.Stable performance increase was led by development of new customers and application market of magnets.