辊式涂布两辊间隙施涂过程的数值计算分析

目的系统地计算涂层厚度与两辊间隙、涂布辊速度以及胶黏剂的流体稠度和流动指数等影响因子的关系。方法在分析该复杂流动机理的基础上,利用CFD软件对具有非牛顿流体特性胶黏剂的两辊间隙施涂过程进行二维数值模拟。结果在五辊无溶剂涂布工程中,两辊间隙增大,最终涂布厚度也明显增大;增大涂布辊转速,涂布厚度也将减小;胶黏剂的流体稠度越大,最终传递到基材上的涂层厚度减小。结论两辊间隙的大小对涂层厚度的影响最大,胶黏剂的流体稠度、流动指数也对涂层厚度有较大的影响。     

五辊无溶剂涂布涂层厚度数学模型与影响因子分析

目的研究如何实现高效的无溶剂涂布,获得稳定的预定厚度涂层。方法在建立两辊间隙间涂布液流动数学模型的基础上,从涂布液辊间间隙分流分配关系和总结构内涂布液流量平衡两方面,分析无溶剂五辊顺转涂布系统涂布厚度的影响因素。结果转移钢辊和涂布钢辊的速比,计量辊和转移钢辊之间的间隙以及橡胶转移辊的压力等是对涂层厚度有直接影响的因子,毛细准数是涂层竖条道缺陷的主要影响因子,而涂布液的非牛顿特性会加重竖条道缺陷。结论设计无溶剂五辊顺转涂布系统时,需要综合考虑辊的直径、施加给橡胶辊载荷大小的范围、橡胶辊的硬度、适用涂布液的粘度范围和速度极限等因素。     

白乳胶涂层厚度光电检测方法及其实现

目的 在硝化纤维纸自动涂布系统中,对涂胶辊上的白乳胶层厚度（0．02－0．025)mm及其均匀性进行检测。方法 提出了一种利用红外线照在光亮的金属表面直接反射回的红外光强度与红外线照在液态白乳胶涂层（厚度（0．02－0．025)mm)上,并透过涂层再从金属表面反射回的红外线强度之差来提取涂层厚度特征信号,从而得到对应检测处涂层厚度信息,检测液体层厚度及均匀性的方法;给出了实现该方法的详实原理图。结果 经实验调试,该方法可有效得到对应涂层厚度及均匀性的电信息。结论 该方法是检测薄层能透光的液态涂层厚度及均匀性的好方法。     

牛顿流体两辊间隙施涂过程的理论建模与分析

目的通过理论建模分析涂膜厚度的成型机理,从而实现对涂膜厚度的精确控制。方法针对牛顿流体在五辊涂布系统存胶辊与计量辊之间微间隙处的流动过程,在机理分析与适当假设的基础上,建立流体流动的数学模型,推导出涂膜厚度与其影响因子之间的关系方程,并分析影响液膜厚度的关键因子。应用CFD软件对流体的流动过程进行数值仿真,通过仿真流场对理论模型与理论推导的边界条件及结果的合理性进行分析。结果表明理论模型与仿真流场一致,理论结果与仿真结果吻合度较高,该理论建模具有相当的合理性。理论结果表明,影响涂膜厚度的因素有涂液粘度和表面张力、计量辊转速、辊径以及辊间间隙,它们与涂膜厚度之间存在较复杂的关系方程。结论有助于在工程实际中快速找到获得理想涂膜厚度的有效工艺参数。     

高强钢辊弯成形过程中成形力的影响因素研究

目的 探究辊弯成形过程中各工艺参数(板材厚度、弯曲角度以及总弯曲角度)对成形力的影响.方法 研究"日"字形截面的辊弯过程,利用ABAQUS有限元软件(FEA),建模分析辊弯成形过程中成形力大小的影响机制,避免实际生产中采集数据的复杂性以及困难性.为了避免各因素之间相互影响,采用单一变量实验法进行实验,根据不同板厚(1....     

涂布器位置的控制

在感光乳剂的挤压涂布中,涂布器位置的控制精确与否,直接影响涂层厚度的均匀性。本发明介绍的涂布装置,由以下几部分组成:一个可调位置的涂布器,一根绕片基的涂布辊,两个传感器和与其相对应的挡板。传感器实际上是一个特殊的复合气嘴,它和压缩空气源相接,造成喷射气流射向挡板,产生反压力。根据传感器测出的反压力值,即可示出涂布器和涂布辊的间隙。传感器和挡板有两种安装方法:一种是将传感器固定于涂布辊轴上,把挡板安在涂     

辊涂机改进设计研究

辊涂机漆耗小、生产效率高、操作简单、维护方便,常被用作带钢涂层生产线中。辊涂机的性能决定了材料表面的涂层厚度和涂层均匀度,对机组作业效率影响重大。随着科学技术的发展,辊涂机也有了新的发展。本文通过了解辊涂机的外观结构、工作原理、辊涂工艺,对新型辊涂机的主要改进方向进行了介绍,探讨未来辊涂机发展。     

精密涂布技术及其应用

精密涂布在印刷包装基材和产品改性方面应用广泛,本文介绍了辊式涂布、刮刀涂布、狭缝涂布和坡流涂布等几种精密涂布方式其应用发展概况。分析表明:狭缝式涂布具有预计量、设备封闭降低污染、涂布更均匀、适于高粘性涂布液和多种基材、可以一次实现多层涂布等特点有望取代辊式涂布。涂布液干燥方式可以采用紫外-发光二极管(UV-LED)光源固化或电子束(EB)固化,减少能量消耗和VOCs排放。精密涂布技术发展方向是在提高涂布速率的基础上进一步提高涂层厚度和均匀性控制能力,加强涂布设备智能化水平。     

涂布工艺对厚膜涂布性能的影响

为了得到一定厚度的厚膜,并保证涂膜表面的平整性,分别采用刮涂法、网纹辊涂布法、以及丝网印刷法进行涂布,改变涂布框厚度、刮刀角度、网纹辊绕线直径、丝网目数和版膜厚度对UV涂布油进行涂布,测试涂布膜层的厚度及表面粗糙度,研究涂布工艺对膜层性能的影响.研究结果表明:采用刮涂法可获得较厚、表面较平整的涂膜,且刮刀角度在45°～60°范围内,另外,采用丝网印刷法也可得到性能较好的涂膜,但版膜厚度应很高.     

聚酯薄膜生产中影响在线涂布薄膜生产稳定性的因素分析

介绍在线涂布聚酯薄膜生产设备、工艺流程,以及对影响在线涂布薄膜发展的涂布膜生产稳定性的因素进行分析。     

涂布技术研究进展

综述了压辊类涂布、刮刀类涂布、挤出涂布、帘式涂布、旋转涂布和喷雾涂布等涂布技术的特点。指出了选择合适的涂布方式、加强涂层在线检测控制和调整涂布液流变特性,是涂布技术向更快、更精发展的重要手段。     

Effects of process parameters on the microstructure of iron coating fabricated on pure aluminum by immersion plating

In this paper, an iron coating was designed to fabricate on the surface layer of pure aluminum. The effects of process parameters such as immersion plating method, durations and temperatures on the microstructure of iron coating were studied systematically. The experimental results showed that the quality of the iron coating fabricated on the sample by one-step immersion plating is better than that obtained by two-step immersion plating. The iron coating obtained by one-step immersion plating for 1 min is continuous and without obvious gaps and cavities. With the immersion time increased to 3 min and 5 min, the coating is uneven and easy to fall off from the surface of sample. Additionally, due to that the higher temperature increases the efficiency of displacement reaction, the quality of the coating obtained at 40 °C is better than that obtained at 55 °C and 65 °C. Consequently, the optimal immersion plating parameters were one-step immersion plating, 1 min, and 40 °C. This paper provides a novel method to prepare an iron coating as a pretreatment for electroplating of aluminum.     

Artificial neural network-based prediction technique for coating thickness in Fe-Al coatings fabricated by mechanical milling

The objective of this study was to evaluate the effect of milling time, milling speed and particle size of initial powders on the coating thickness of Fe-Al intermetallic coating by using artificial neural network (ANN). Coating morphology and cross-section microstructures were evaluated using a scanning electron microscope (SEM). It was found that an increase in the milling time provided an increase in the coating-layer thickness due to the cold welding process between particles and the steel substrate. The microstructure of the coating surface was refined by ball impacts in the milling process. As a result of this study, the ANN was found to be successful for predicting the coating thickness of Fe-Al intermetallic coatings. The correlation between the predicted values and the experimental data of the feed-forward back-propagation ANN was quite adequate. The mean absolute percentage error (MAPE) for the predicted values didn’t exceed 7.46%. The ANN model can be used for predicting the coating thickness of Fe-Al intermetallic coating produced for different milling time, milling speed and particle size.     

Zn-Ni-V热浸镀层组织及腐蚀电化学行为研究

在锌浴中添加少量的Ni和V,获得了Zn-0.05%Ni-0.05%V镀层.研究了Zn-0.05%Ni-0.05%V镀层组织和在5%NaCl溶液浸泡过程中的腐蚀行为.结果表明:在Zn-0.05%Ni镀浴中添加0.05%V可以有效地抑制Fe-Zn反应,控制ζ相层的超厚生长.与Zn-0.05%Ni镀层相比,浸泡20min后,...     

石墨烯涂层对直升机旋翼防/除冰组件传热的影响

采用水性和油性石墨烯涂层对复合材料防/除冰组件进行测温及防/除冰实验.针对直升机旋翼对结冰的敏感等特点,提出了旋翼防/除冰组件包铁表面涂覆石墨烯涂层改性传热性能的方法,从而提高旋翼防/除冰组件除冰效率.为验证石墨烯涂层对防/除冰组件传热效率具有显著的提高作用,采用搭建的除冰实验平台并对涂覆的旋翼防/除冰组件进行传热实验...     

Cast joining of cast iron to aluminium casting matrix

Abstract

The present study focused on reinforcing Al–Si–Cu alloy with a cast iron insert and using Zn–xAl–3Si–0·5Mg (wt-%) intermediate alloys by the cast joining technique to take advantage of lightness and stiffness of the hybrid structure. The experimental set-up consisted of coating the insert using hot dipping method followed by immersing the coated insert into the Al melt and allowing the system to cool down to the room temperature. The quality of Al–Fe joints in terms of morphology, thickness, chemistry and microhardness was evaluated as a function of coating composition and immersion time in the Al melt. Characteristics of reaction layer at the coating/insert interface and its effects on the joint properties were determined using microstructural analysis and thermodynamic calculations. Combination of a suitable coating containing 27 wt-%Al and optimised process parameters, including 1 min immersion time, resulted in the formation of an Al–Fe joint with promising characteristics.     

医用钛合金微弧氧化膜的制备及其生物适应性能

在钛及钛合金表面生成羟基磷灰石（HA）来制备生物材料是医学应用中亟待解决的问题。利用微弧氧化工艺在Ti合金表面制备了HA膜,研究了膜层在模拟体液中浸泡前后的形貌、相结构、Ca与P原子分数比,并分析了膜层在模拟体液中的降解和沉淀机制以及浸泡后的耐磨性。结果表明：膜层在模拟体液中随浸泡时间延长而逐渐变厚;浸泡20d后膜层中...