电气石超细粉体表面修饰的研究

用不同修饰剂对电气石超细粉体进行表面修饰,并用沉降法、接触角、亲油度和红外光谱表征了表面修饰效果.实验表明,钛酸酯的表面修饰效果优于聚乙烯醇和硅氧烷.考察了经修饰的电气石超细粉体在聚酯切片中的分散效果,最终制得的PET纤维具有很好的负离子释放性能.     

超细粉体技术在无机矿物填料中应用的研究现状

综述了超细粉体技术在无机矿物作为橡胶补强填充剂中的应用。介绍了近年来超细粉碎技术、超细粉体的表面改性技术运用于无机矿物填料的研究现状。经超细粉碎、改性后的无机矿物可全部或部分代替炭黑等常规橡胶填料，从而降低橡胶生产成本。     

超细电气石粉体的表面改性试验研究

超细电气石粉体在使用基体中的分散性直接影响其释放负氧离子的性能.本文以提高超细电气石粉体在亲水性体系中的分散性为目的进行了表面改性研究.通过对超细电气石粉体的聚丙烯酸改性处理,并通过对改性前后的样品进行红外光谱分析分析了改性机理.结果表明,对超细电气石粉体进行表面改性时,聚丙烯酸的最优用量为电气石粉体质量的1.0%,改性处理后样品在水中的分散性大大提高.红外光谱分析表明,聚丙烯酸与电气石粉体表面的结合方式为化学吸附.     

滑石粉超细粉碎过程物理化学性质的变化

超细粉体在现代工业中具有重要的地位，超细粉碎的一个重要作用是为现代新材料提供高性能的粉体，然而超细粉碎过程中并不是一个简单的物料粒度的减小，还包含了许多复杂的机械化学变化，本工作研究了滑石粉超细粉碎过程物理化学性质的变化，讨论了物理化学性质变化的相关机理，研究表明：,滑石粉经搅拌磨超细粉碎后，表面活性增强，热效应改善，白度提高，粉体性质变化与超细粉碎过程的热力学特性密切相关。     

负离子功能PET纤维的研制

选择超细电气石粉末作为新型功能添加剂,通过偶联剂表面修饰,对改性效果进行比较和表征,并制备了负离子功能聚酯纤维。研究了超细电气石粉末的表面改性及其在高分子基体中的分散性,以及PET共混体系和负离子功能纤维的性能。主要研究结果如下:对超细电气石粉末的表面改性,采用单烷氧型钛酸酯5%处理量的处理效果较佳,在普通纺丝速度范围内,PET共混体系的可纺性与PET一样稳定。经测试,试验纤维具有良好的物理机械性能和负离子发射功能(大于4500个/cm3)。     

我国超细粉碎与超细分级技术的现状及问题

近年来 ,我国的超细粉碎与超细分级技术有很大的发展 ,但在发展过程中存在着一些问题。超细粉体涉及的行业众多 ,但对其粒度的分类至今国内尚无定论。通过调研 ,分析了目前国内超细粉碎设备的现状。对超细粉体分级技术中的干法分级和湿法分级作了比较全面的介绍 ,并对我国超细粉碎与超细分级技术的发展提出了建议     

湿法超细研磨中无机材料浆体的流变性研究

概述了无机材料超细粉体机械研磨制备中浆体的流变性能、流变性能的表征方法和流变学行为的经验方程模型.对影响超细粉浆体流变性能的参数(如固相含量、颗粒粒径和分布、形状、温度、pH值及分散剂)进行了讨论.对浆料流变学性能进行最优化以提高超细粉体的产量,降低能耗,提高产品细度.提出了今后的研究重点应放在湿法超细研磨过程中分散剂种类及用量对浆体流变学性能改变机理的研究,并建立可描述浆体流变性能与粉碎参数、分散剂用量、能耗和颗粒大小的数学关系.     

超细粉体制备技术的应用和发展

介绍了超细粉体的制备方法，重点对超细粉碎设备，工艺及应用领域作了详细评述。     

南京理工大学向法国 出口超细粉碎设备

由南京理工大学研制的一套超细粉碎设备日前被法国ＳＤ -Ｔｅｃｈｓ．Ａ公司购买 ,将于近日运往法国马赛。法国ＳＤ -Ｔｅｃｈｓ．Ａ公司多次派员到南京理工大学粉体中心现场粉碎 ,试验考核 ,并与德国和日本等国同类产品进行比较 ,结果证实南京理工大学的超细粉碎设备达到欧洲的相关标准 ,决定购买此套设备。超细粉体工程技术是当今国际上研究的热门课题之一。该项技术与日用化工材料、农业、国防和航空等诸多领域密切相关。南京理工大学超细粉体工程技术的研究在国际学术界占有一席之地南京理工大学向法国出口超细粉碎设备@沈镇平…     

负离子铸铁搪瓷的研制

通过将电气石磨加到铸铁搪瓷面釉中,并对铸铁搪瓷的制作工艺进行合理设计,获得了具有产生负离子功能的铸铁搪瓷。经ITC-201A Smart IonsMonitor负离子测试仪检测,其发射负离子最高可达28090个/cm3,1m in平均值为1160个/cm3。用X-射线衍射(XRD)和扫描电镜(SEM)对负离子铸铁搪瓷的晶体结构和显微结构进行分析,结果表明,该铸铁搪瓷面釉中所磨加的电气石,经过涂搪烧成后,其晶体结构没有发生相变,仍为六方柱状晶体。从而得出结论:磨加电气石超细粉体是使该铸铁搪瓷获得负离子功能的主要原因。     

不同来源的黑电气石粉对活性蓝49的降解作用研究

文章优选对染料废水脱色效果最佳的黑电气石粉,发现来自江西的黑电气石粉对活性蓝49的降解效果最佳;pH为2.0,对100 mg/L的活性蓝49溶液的脱色率为92.6%。该黑电气石粉的矿物成分介于镁电气石与铁电气石之间,属于两者的过渡类型。通过UV-Vis紫外光谱图、FTIR谱图及X射线衍射谱图初步分析了来自江西的黑电气石粉对活性蓝49的脱色机制,结果表明黑电气石粉具有破坏染料分子结构中的共钮发色体系,使在可见光区染料溶液的最大吸收峰消失;但不能破坏含有苯环、荼环等小分子的物质的结构。黑电气石粉降解染料废水是不改变其化学结构的,不过其晶体内部的能量和结构位置发生了变化。     

Negative air ions releasing properties of tourmaline contained ethylene propylene diene terpolymer/polypropylene thermoplastic elastomers

The releasing properties of negative air ions of tourmaline contained polypropylene (PP) and ethylene propylene diene terpolymer/polypropylene (EPDM/PP) composite films under varying testing conditions were investigated in this study. It is interesting to note that the C_ion− values of EPDM/PP/tourmaline specimens tested at varying conditions are significantly higher than those of the PP/tourmaline specimens with the same loadings of tourmaline powders. Moreover, all C_ion− values of PP/tourmaline and EPDM/PP/tourmaline film specimens tested at dynamic impact mode are significantly higher than those of the corresponding specimens tested at static mode but the same temperature. A beneficial temperature effect on C_ion− values of the PP/tourmaline and EPDM/PP/tourmaline film specimens tested at static and dynamic impact conditions was found. To understand these interesting negative air ion properties of PP/tourmaline and EPDM/PP/tourmaline film specimens, energy dispersive X-rays analysis of the tourmaline powders, scanning electron microscope morphology, and tensile property analysis of the PP/tourmaline and EPDM/PP/tourmaline film specimens were performed. Possible reasons account for the interesting negative air ion properties of the PP/tourmaline and EPDM/PP/tourmaline film specimens are discussed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Influence of process parameters on breakage kinetics and grinding limit at the nanoscale

In long‐term milling experiments, in a stirred media mill, a grinding limit where no further particle breakage occurs was identified. During mechanical stressing of the particles, defects are generated in the crystalline lattice, which allows real fracture of nanoparticles. Below a critical size, defects cannot be stored or generated in the crystallites and the overall limit of grinding is reached. This limit is strongly influenced by material properties and hardly affected by most of the process conditions. However, the breakage kinetics strongly depend on the process parameters and suspension conditions as long as the grinding limit is not reached. Based on these findings, two mechanisms of nanoparticle breakage are proposed. Proper choice of process parameters saves not only up to 90% of the energy input to reach the grinding limit but also leads to a higher product quality in terms of crystallinity and less milling bead wear. © 2010 American Institute of Chemical Engineers AIChE J, 2011     

机械力化学合成纳米晶PZT的研究

通过研究PbO-ZrO2-TiO2机械力化学过程,探明了机械力化学法制备PZT纳米粉体的工艺条件。在一定操作参数的条件下(公转转速250 r/min,自转转速为62.5 r/min)粉磨60 b,能够制备出10～30 nm PZT纳米粉体。采用XRD,DTA,SEM,TEM对不同粉磨时间的混合粉体进行表征分析。发现机械力化学合成纳米粉体经过颗粒细化、晶粒尺寸减小、晶格畸变、混合物粉体无定形化、固相反应等阶段。铅黄型PbO经高能球磨晶型转变为密陀僧型PbO,混合物粉体保持化学计量。     

Enhanced mechanical properties of 3 Y2O3 stabilized tetragonal ZrO2 incorporating tourmaline particles

The current study reports on the improvement of mechanical properties of 3?mol% Y₂O₃ stabilized tetragonal ZrO₂ (3Y-TZP) by introduction of tourmaline through ball milling and subsequent densification by pressureless sintering at 800, 1200, 1300, 1400?°C. Findings demonstrate that no matter which sintering temperature the 3Y-TZP ceramic containing 2?wt% tourmaline reach a maximum value in flexural strength and fracture toughness as compared to other composite ceramics. As the tourmaline content is 2?wt% and the sintering temperature is 1300?°C, the flexural strength and fracture toughness of the composite ceramics are the highest, increases of 36.2% and 36.6% over plain 3Y-TZP ceramic respectively. The unique microstructure was systematically investigated through X-ray diffraction, scanning electron microscopy, energy dispersive spectrum, and flourier transform-infrared. The strengthening and toughening mechanism of tourmaline in 3Y-TZP ceramic were also discussed.     

Fabrication of porous structure vitrified bond diamond grinding wheel via direct ink writing

Porous vitrified bond grinding wheels with complex structure, high porosity, controllable pore size have fundamental application in high efficiency and precision grinding of hard and brittle materials. In this paper, direct ink writing (DIW) is proposed to fabricate three kinds of grinding wheels, including solid structure, triangle structure, and lattice structure. Moreover, the rheological property of ceramic ink with different doses of xanthan gum (XG) solution was investigated to ensure printability, demonstrating 3% XG solution can meet requirements. Additionally, the effect of sintering temperature and pore former (PMMA) contents on size shrinkage rate, morphology, mechanical strength, and porosity et al. were studied. The results indicate that the diamond grinding wheel with 30 vol% PMMA and sintered at 670 °C possess the best comprehensive performance. Besides, grinding performance was evaluated by surface morphology, surface roughness, and material removal rate. Among the DIW-fabricated wheels, triangle structure grinding wheel and lattice structure grinding wheel possess a higher material removal rate than solid structure grinding wheel. Therefore, the porous structure grinding wheels fabricated by DIW present the advantage of controllable porosity, excellent self-sharpening ability, and higher bond strength, which may pave the way for designing a new generation vitrified bond diamond grinding wheel.     

电气石粉体表面改性及其应用研究进展

电气石是环状结构硅酸盐矿物,因其具有压电性、远红外性等特性而具有巨大的应用价值。从改性方法、工艺、表面改性剂及其配方等方面综述了电气石粉体表面改性现状,重点介绍了机械力化学改性法和表面有机包裹法及其相应的改性原理与基本工艺流程;概述了改性后的电气石粉体在水处理﹑医疗保健﹑节能环保﹑纺织等方面的应用情况;并对电气石粉体改性的发展趋势及其应用前景做了展望。     

Key technologies for laser-assisted precision grinding of 3D C/C-SiC composites

Due to their exceptional and distinctive qualities, 3D C/C-SiC composites are widely utilized in producing high-end equipment and the aerospace national defense industries. However, the hard and pseudo plastic nature of the material and its anisotropies make it challenging to process. To improve the processing quality of 3D C/C-SiC composites, laser-assisted precision grinding technology is introduced in this paper, which innovatively controls the depth of the thermally induced damage layer by adjusting the laser process parameters to reduce the hard brittleness of the material, and then the surface is created by precision grinding with a grinding wheel on this basis. Experiments on laser-induced damage, laser-assisted grinding, and diamond scratching were carried out to investigate the effect of laser parameters on material damage and the effect of laser-assisted grinding processes, with an emphasis on revealing the mechanism of material removal. The results show that laser irradiation causes complex reactions such as sublimation, decomposition, and oxidation of 3D C/C-SiC composites, resulting in SiO2 and Si and recondensed SiC, causing surface/subsurface damage. A maximum reduction in normal grinding force, tangential grinding force, specific grinding energy, and surface roughness of 35.6%, 43.6%, 43.58%, and 24.22%, respectively, compared to conventional grinding processes with laser-assisted grinding. After laser irradiation, the degree of brittle fracture in the precision grinding of workpieces is significantly reduced due to the degradation of matrix and fiber damage caused by laser irradiation, which reduces the hard and pseudo plastic properties of the material. The removal mechanism shows a trend of ductile domain removal in the grinding of thermally damaged layers, which reduces the grinding force and improves the surface quality.     

滑石粉超细粉碎过程的结构变化

研究了滑石粉在超细粉碎过程中晶体结构的变化,讨论了结构变化的机理。研究表明,滑石粉经搅拌磨超细粉碎后,表面活性增强,晶体结构的无序化程度加剧。定量地计算了滑石粉晶体结构的变形度。     

Effects of Mechanical Treatment on X-ray Diffraction Line Broadening in Pyrophyllite

When pyrophyllite was subjected to mechanical treatment by dry grinding, the alteration was greater along the c axis of its structure because reflections from basal planes (00 l ) disappeared well before those from nonbasal planes, producing anisotropic X-ray line broadening observed on grinding. X-ray analysis showed that the mean lattice microstrains increase and crystallite size decreases along the 00 l direction, as grinding time increases. An inverse relationship between both parameters was found, and interpreted assuming that the number of grain boundaries of the small crystallites increases substantially through mechanical treatment. The maximum surface area of ground samples was reached after 30 min of grinding, with marked line broadening, mean crystallite size of ∼15 nm, and lattice microstrains 0.68. Reactive ground material aggregates, becoming amorphous to X-rays, and surface area decreases markedly.