提高粉末涂料在静电喷涂中死角上粉率的工艺技术研究

介绍并探讨在静电喷涂中影响死角上粉率的各种因素,提出了调整粉末配方和喷涂工艺的具体工艺措施,有效地提高了粉末在静电喷涂中死角的上粉率,为减弱粉末涂装过程中的法拉第笼效应屏蔽提供一种可能性。     

影响粉末涂料上粉率因素的探讨

介绍了粉末涂料静电喷涂原理，分析了影响粉末上粉率的因素，并提出提高上粉率的工艺条件。     

粉末喷涂系统的进展

静电粉末喷涂设备自60年代到80年代末,已经历了好几代的重大改革,使粉末喷涂系统越来越趋完美。90年代初又提出了新的要求,就是提高设备的自动化程度或喷涂系统的过程控制,以达到理想的上粉率,即把粉末涂料转换成漆膜的能力。对喷涂系统来说,Reddy 提出必须提高上粉率。提高上粉率的最有效方法是在喷枪前面没有工件     

OSB表面环氧聚酯粉末涂饰探究

本研究以OSB为基材,通过静电喷涂将环氧聚酯粉末喷在OSB表面,再经红外熔融固化,制得粉末涂饰的OSB,并测其涂膜性能。结果表明,粉末涂饰OSB的制备条件是:采用水性透明腻子涂抹基材,粉末涂料单位面积上粉量为144.79~168.92 g/m2,涂膜红外固化条件为150℃/5 min。试样涂膜附着力为1级,耐磨性为3级,铅笔硬度为2H,耐冲击性、耐丙酮、耐水蒸气、耐污染、耐干热和耐酸碱性等性能都达到了木漆涂饰国家相关标准规定要求。     

影响摩擦枪粉末涂料带电量的因素探析

通过理论结合试验的方法,探讨了粉末涂料在摩擦喷涂过程中,影响摩擦带电量的各种因素。研究了摩擦助剂、粉末粒径、粉末类型、气压大小对带电性能以及工件上粉率的影响。     

静电粉末喷涂中一次上粉率浅析

分析了静电粉末喷涂中影响一次上粉率的主要因素以及在应用中如何提高一次上粉率。     

市场趋向

正超细粉末涂料市场前景广阔粉末涂料是环保型涂料,发展空间大。但普通粉末涂料的缺点是涂层厚度太厚(通常在60~100μm,大大超过传统液体涂料的厚度)、平整度差、光泽低、粉末喷涂量多等。普通粉末涂料的上述缺点限制了其推广应用。上述缺点可以通过降低粉末颗粒粒径的方法来解决。普通粉末涂料颗粒粒径一般为30~40μm,粒径小于30μm为细粉末涂料,粒径为10~20μm为超细粉末涂料。超细粉末涂料的涂层薄(30~40μm,接近液体涂料的水平)、平整度好、光泽高、粉末     

基于正交试验设计的碳纤维对PA 12的静电吸附

采用碳纤维和热塑性工程塑料——聚酰胺(PA)12粉末作为模型,通过静电流化床的静电吸附作用,使固定在流化床上的碳纤维吸附PA 12。研究了吸附时间、静电压、气流压力、碳纤维剥离数、碳纤维种类以及PA 12粉末粒径等对PA 12与碳纤维质量比(记作P/F)的影响规律,并借助正交试验,得出扩大试样P/F的最佳工艺参数。结果表明:静电吸附实验中,碳纤维应放置在吸附室的中间,且与操作者平行;静电流化床的宽度减小,P/F也相应减少;若将PA 12粉末粒径由70 μm减少至8 μm,吸附效果会变差;当PA 12粉末粒径为70 μm时,能够得到最佳P/F的工艺参数:吸附时间为1 min,静电压为30 kV,气流压力为0.14 MPa,碳纤维剥离数为4束,纤维种类为3 k。     

粉末静电喷涂在冰箱涂装中的应用

阐述了粉末静电喷涂工艺的基本原理和粉末涂料固化成膜的机理;介绍了粉末静电喷涂技术在科龙公司冰箱涂装线上的应用,分析了固化成膜后的涂膜外观质量。     

静电粉末喷涂及应用

<正> 静电喷涂是传统的喷涂和静电效应相结合的一项新技术,它具有良好的表面涂层质量,防止环境污染,生产效率高,综合经济效益好等特点,因此得到了广泛的应用并获得迅速的发展,静电喷涂包括静电喷涂和静电粉末喷涂(或称静电喷粉、静电喷塑)。本文将介绍静电粉末喷涂原理及工艺流程,粉末涂料品种,以及静电粉末喷涂的特点等内容。     

矿渣微粉粒度分布对水泥性能的影响

利用灰色关联分析方法,研究了矿渣微粉的粒度分布对矿渣水泥性能的影响。研究结果表明:0~5μm、5~11μm的矿渣微粉颗粒分别对3 d、28 d强度有显著影响;0~23μm的矿渣粉颗粒对3 d,28 d强度起增进作用;水泥强度随23μm的矿渣微粉颗粒含量增大而降低。因此,可以通过优化矿渣微粉的粒度分布来改善水泥性能。     

Effect of Hollow Spherical Powder Size Distribution on Porosity and Segmentation Cracks in Thermal Barrier Coatings

The effect of characteristics of hollow spherical (HOSP) powders on porosity and development of segmentation cracks in plasma-sprayed thick thermal barrier coatings (TBCs) was investigated. Three powders with particle size ranges of 20–45, 53–75, and 90–120 μm were selected from a commercial HOSP powder feedstock for spraying the TBCs. The 20–45 μm powder has a higher deposition efficiency and a greater capability of producing segmented coatings than the other larger powders. Diagnostics of in-flight particles show that the average surface temperature and velocity of the particles sprayed from the fine powder is higher by 250°C and 50 m/s compared with those sprayed from the 90 to 120 μm powder, respectively, due to its greater ratio of surface area to mass. The lower porosity of the coating sprayed from the fine powder is mainly attributed to the decreased volume of intersplat gaps and voids.     

微米铝粉在声场中的振荡燃烧特性

为了解声场中铝粉的燃烧特性,建立了甲烷平面燃烧器,利用外置喇叭产生振荡,进行了微米级铝粉的燃烧实验。研究了铝粉在不同振荡频率下的分布燃烧响应特性及粒径分别为10、20、30μm的3种铝粉颗粒的燃烧特性和产物的阻尼特性。结果表明,振荡频率不同时,铝粉燃烧对振荡压强的增益作用不同,粒径为20μm铝粉燃烧,在振荡频率200Hz和300Hz时增益作用明显。铝粉粒度越大,分布燃烧增益越大。粒径为10μm铝粉对燃烧器高频振荡阻尼最大。随着铝粉粒度增加,燃烧产物颗粒对高频压强振荡的阻尼减小。     

Investigation of the recyclability of powder coatings

100% recyclability is one of the major advantages of powder coating. However, it can never be achieved in reality. Coating powders, especially finer powders with particle size below 30 μm, were found to have much worse flow performances after recycling from electrostatic spraying so as to decrease the recyclability. Therefore, this study was designed to investigate recycled coating powders to determine the underlying cause of decreased flow performance. The investigations were based upon three major factors that make the differences between original powder and its recycled powder: particle size, humidity exposure and flow additive concentration. By adjusting the three factors independently, the influences to powder flow properties were analyzed. Results showed that the decreased particle size of the recycled powder had the most significant effect on the flow properties. Additive concentration on the powder particles did not change with respect to the particle specific surface area after electrostatic spraying. Humidity had only a minor effect on the flow properties of powder coatings.     

Study on the relationship between the particle size distribution and the effectiveness of the K‐powder fire extinguishing agent

The relationship between the particle size distribution and the extinguishing effectiveness of the new K‐powder fire extinguishing agent has been studied experimentally, to explore the reason of the great extinguishing efficiency exhibited by the new K‐powder fire extinguishing agent on Class B fire (liquid fuel fire). The results of the experiment showed that the extinguishing effectiveness increased along with the decrease of the particle size distribution. In addition, a sharp discontinuity appeared around the limiting size, about 40 μm. The powder with the particle size below 40 μm exhibited highly effective extinguishing with the minimum effective extinguishing concentration C_xr = 23 g·m^?3, while the powder with the particle size above 40 μm exhibited little fire extinguishing efficiency. Compared with other fire extinguishing agents produced by different substances, the new K‐powder fire extinguishing has the bigger limiting size. That means, in the same particle size distribution, the new K‐powder fire extinguishing agent contains more highly effective powder than others contain, and is more effective.     

细粉粉末涂料流动性能的表征研究

为了更好地解决细粉及超细粉末涂料颗粒在加工、气流输送、喷涂等工艺中遇到的问题,本文对影响细粉粉末涂料流动性能的各粒径参数进行了实验研究和回归分析。研究发现:工业上通常应用中粒径(D50)来表征细粉涂料流动性并不够准确。通过对不同特征粒径以及粒径分布跨度等因素的考察,本文提出了一种由代表粒径大小和粒径分布的D10-D50-D90多变量关联模型来表征细粉粉末涂料流动性的方法,使细粉涂料流动性的预测更为可靠和准确,为细粉涂料特别是超细粉末涂料的工业应用提供理论指导。     

青黛粉体提取研究

研究提取不同粒径青黛的溶出情况。考察了以氯仿为溶剂，青黛的一次提取，三次提取，超声提取，实验表明随青黛粉体粒径的减小，一次提取的平衡浓度和速率都会增加。随温度的升高，粒径减小对青黛中靛蓝的一次提取平衡浓度影响更为显著。三次提取时，靛玉红提取率随粒径减小增加明显。推断超细粉体对提取含量小的组分，或发挥小含量的组分药效更有价值。长时间超声提取，提取液中靛蓝、靛玉红浓度舍再次升高。     

超细Fe粉改性聚甲醛的研究

研究了超细Fe粉对聚甲醛（POM）的改性效果,结果表明：Fe粉粒径越小增强增韧效果越好,粒径为140 nm的Fe粉增强效果优于粒径为1 μm的Fe粉。分散剂TAS-2A的分散效果最好,其用量为Fe粉含量1.5 %~2.0 %时效果最佳。钛酸酯偶联剂处理Fe粉效果优于硅烷类偶联剂,其中钛酸酯偶联剂NDZ-201最适合POM/Fe复合材料,其用量为Fe粉含量的2.0 %时效果最好。Fe粉含量为4 %时,POM/Fe/ NDZ-201复合材料的冲击强度达到9.6 kJ/m2,较纯POM提高4.6 kJ/m2。     

高活性微米多孔铝粉的制备与表征

为得到具有高活性多孔铝粉和氢化铝共存的混合体系,在常压下采用格氏试剂法对普通铝粉进行活化,通过半固相反应得到高活性微米多孔铝粉,用红外光谱、X射线衍射、扫描电子显微镜、静态氮吸附等方法对样品进行了表征,通过氧化还原滴定法测试了微米多孔铝粉的活性。结果表明,制备所得样品的主要成分是铝粉,同时还有部分AlH3;样品具有多孔结构,粒径多数分布在30μm左右,不仅具有孔径在2~10nm之间的中孔,还存在孔径分布在1nm以下的部分微孔结构;总孔体积为普通铝粉的5~7倍,比表面积为普通铝粉的2~3倍,样品平均活性含量达到92.83%。这种含有AlH3的高活性微米多孔铝粉混合体系在含能材料领域有很大的应用价值。     

Powder production via electrohydrodynamic-assisted molten metal jet impingement into a viscous medium

In this paper, a novel method for preparing metal powder with the aid of electrohydrodynamic (EHD) force is introduced. A pneumatic based atomization apparatus was constructed for this study. Solder melt jet is injected from a 250 μm ID nozzle onto a viscous medium (transformer oil). As a result of jet impingement and penetration into the oil, the melt jet disintegrates into micro-sized droplets and ligaments by a combination of the natural jet breakup phenomenon and EHD atomization. Due to the presence of electrostatic forces, the disintegrated droplets and ligaments repel each other and therefore particle coalescence and agglomeration is minimized in this method. The breakup was captured with a high speed camera. The morphology and structure of the obtained powders were investigated using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD), respectively. Morphology of the particles was controlled by varying the oil temperature and the EHD voltage. Structure investigations show that a decrease in particle size leads to an increase in interior microstrain. Also, interior microstrain increases by decreasing the oil temperature. The main advantage of the developed method is to produce fine powder with controlled characteristics such as size, size distribution, morphology and structure.