不同B_(4)C含量对冷喷涂Al/B_(4)C复合涂层防腐与耐磨性能的影响

目的分析不同B_(4)C含量对冷喷涂Al/B_(4)C复合涂层防腐和耐磨性能的影响,探索利用冷喷涂低温特点制备Al/B_(4)C复合涂层的可行性。方法利用冷喷涂方法制备4种B_(4)C含量的Al/B_(4)C复合涂层,并利用各种方法表征涂层的结合特征、耐磨性能和防腐性能。结果冷喷涂过程不会改变铝和碳化硼的物相,碳化硼颗粒主要以嵌入方式结合在涂层中,会产生结合缺陷。在本研究中,B_(4)C的质量分数最高可达到34.53%左右,涂层的结合强度随粉末中碳化硼含量的增加先增加、后降低,最高可达26.67 MPa。微区电化学试验分析涂层内部微电位差值,发现Al/B_(4)C界面存在电位差,腐蚀反应会优先在Al/B_(4)C界面发生,从而破坏金属Al成膜,使涂层的耐蚀性能与略低于铝块材。结论冷喷涂技术可以制备微观结构和结合性能良好的高B_(4)C含量Al/B_(4)C复合涂层,涂层中B_(4)C的质量分数最高达34.53%,预期具有良好的热中子吸收性能。同时,B_(4)C颗粒的加入,使得涂层的耐磨性能大大的提升,但是耐蚀性能相比于铝材料略有降低,是未来需要改善的方向。     

电容式湿度传感器温-湿-盐雾耦合环境损伤效应与机理研究

目的 研究电容式湿度传感器在温-湿-盐雾耦合环境作用下的性能退化规律和失效机理。方法 将电容式湿度传感器放置在三因素循环(85 ℃+85%RH→40 ℃+0.05%NaCl中性盐雾→35 ℃+50%RH干燥)环境下进行加速老化试验,定期取样,分析响应时间和测量精度退化规律,研究温-湿-盐雾对电容式湿度传感器的环境损伤机制。结果 在三因素环境下老化7 d,湿度传感器在标准湿度(>50%RH)环境下感应异常;老化14 d,湿度传感器在每种标准湿度环境下感应异常。测试发现,湿敏电容的电容量偏大,绝缘电阻偏小,损耗角正切偏大,确定湿敏电容失效。湿度传感器在温-湿-盐雾环境下,在盐雾阶段,盐粒子沉积在湿敏材料表面,在干燥阶段水分挥发,最终在湿敏材料表面形成不规整颗粒物,造成湿敏电容绝缘性能降低。在通电测试时,不规整颗粒物在电场作用下易发生尖端发电,使得感湿材料绝缘性能下降,同时伴随有腐蚀和击穿烧蚀,使湿敏电容发生失效。结论 湿度传感器在温-湿-盐雾环境下,盐粒子易附着在感湿材料上,在通电环境下发生击穿烧蚀,造成湿度传感器功能失效。     

4种紧固件用涂层性能对比分析

目的 将4种不同涂料涂覆在相同紧固件上,在相同测试条件下研究它们的表面形貌、耐腐蚀、抗疲劳等性能,最后从中筛选出可替代传统HW-A的潜在涂料,进一步丰富现役钛合金紧固件表面涂层材料品种。方法 利用3D共聚焦、电化学阻抗谱、中性盐雾、加速环境谱等方法评价紧固件表面涂层性能,研究每种涂层的截面形貌、表面形貌、粗糙度、抗腐蚀、加速疲劳寿命等,然后综合分析其关键性能。结果 采用3D共聚焦、电化学阻抗谱、中性盐雾、加速谱等方法初步摸清了4种涂料的性能特点,PTFE涂料的表面粗糙度较CZ和GO降低约50%,PTFE电化学阻抗谱半径较其他3种涂层大大提高。加速谱更清晰表明,PTFE涂料比现役HW-A铝涂料的疲劳寿命提高22.8%,PTFE涂料能满足当下性能需要。结论 PTFE涂料较市场上筛选出的石墨烯涂料、含铬酸盐聚氨酯涂料的施工性能更好、关键性能更优、更适合紧固件使用,在未来产品应用中有较大的潜力。     

钢棒去皮机除尘器设计

钢棒去皮机是通过砂轮磨削除去钢棒表面铁锈的一种设备，在去皮过程产生的大量金属粉尘，导致环境污染，为此设计喷淋塔式除尘器作为钢棒去皮机的除尘装置。通过选择和计算的运行参数，设计了喷淋塔的结构和尺寸。对设计的除尘器效率验算结果表明：该除尘器可以满足去皮机环保要求，除尘效率达99．7％。     

水泥窑烟气SNCR脱硝技术喷枪的设计及应用

对脱硝技术喷枪进行了结构设计和试验分析,结果表明,该结构喷枪能够使还原剂的雾化颗粒平均直径在50μm,均匀度在85%以上,雾态氨水喷射可视距离在4 m以上;枪体采用的0Cr18Ni9耐热不锈钢能够抵抗喷枪在分解炉内的高温变形。在日产5 kt的冀东某新型干法水泥生产线烟气SNCR脱硝项目中得到了应用,脱硝效率达70%以上。     

汽车喷漆、烤漆修理厂存在的事故隐患及治理对策

介绍了汽车喷漆、烤漆修理厂的事故隐患,采取的整改措施。整改后将使其达到安全卫生条件。     

采用花岗岩水膜除尘器燃煤锅炉脱硫和除尘的工艺改造

为了使现有花岗岩水膜除尘器的燃煤锅炉烟气净化达标排放,在不更换水膜除尘器的前提下,探讨和比较了后继烟气吸收装置喷淋塔和鼓泡塔的脱硫和除尘机理,提出改进措施。该技术具有工艺流程简单,建设和运行成本低,适用于由于历史原因仍有相当大数量使用的花岗岩水膜除尘器的烟气净化工艺路线的改造。     

Spray atomization characteristics as a function of pesticide formulations and atomizer design

Abstract

The use of formulation adjuvants to increase the drop size of pesticide sprays has followed a practice which has evolved through many years of experimentation and development. The earliest materials used were simply designed to make the spray mix viscous on the premise that a mayonnaise‐like fluid would produce larger drops and hence increase the deposit efficiency. These viscomer materials, emulsions and water soluble thickeners such as starch and agars, as well as more complex cellulose materials, produced thick non‐Newtonian fluids which were difficult to mix, pump and spray, and provided questionable results. First, the larger drops reduced target coverage from a given volume of spray; and second, field tests with these definitely showed that a large volume of small drops were still being produced even with the thickest of formulations.

The next step in adjuvant evolution was the introduction of polyvinyl, polyacrylamide and polyamide elastomer materials. These polymers are also non‐Newtonian, but due to their peculiar molecular bonding, they have the capability of forming long string‐like streams which when atomized can retract into a spray of large drops. Pure forms of these polymers are blended by commercial producers to enable compatibility with pesticide chemicals. We have conducted a series of laboratory and wind tunnel tests; first, to try and establish some physical parameters identifying their characteristics and second, to determine how these adjuvants affect atomization and the production of small drift‐prone drops (i.e., those smaller than 120 μm in diameter).

Our results with the laboratory studies of physical properties and of the wind tunnel drop size tests have been inconclusive. The elastomer materials have relatively low viscosity (1.5 to 6 mPa.s) and reduced surface tension (50 to 60 mN/m) but our stream‐flow extension tests were non‐productive. The drop size studies comparing water sprays with polymer‐water mixtures gave us a mixed picture. Generally drop size was increased for all of the fan (deflector and milled orifice) and cone type atomizers. But an increase was also indicated of the volume of spray in drops less than 120 μm showing that the polymer did not fully control the production of these small drops under all of the testing procedures we studied.

It is difficult to evaluate the capability of these additives for controlling or reducing production of the drift‐prone small drops. While the pure solutions of the water soluble polymers would appear to be capable of this desirable effect, it is also evident that in order to make these formulations compatible with pesticide spray solutions, several other solvents, emulsifiers and surface active chemicals are added to the formulation, thus affecting the atomization characteristics and hence their drift‐control capability.     

家具企业喷涂过程呼吸防护技术应用研究

随着家具行业持续高速发展和从业人数的不断增加,家具企业职业危害的严峻性也日益突显,职业危害预防、控制也越来越受重视。喷涂作为家具表面处理的重要工艺,其作业过程产生的漆雾和挥发性有机化合物更是直接威胁到职工的健康安全。基于对家具企业喷漆作业场所的有毒、有害因素分析研究的基础上,从个体职业危害防护的角度,提出适用于家具企业喷漆过程的固定式长管呼吸装置防护技术,加强对家具企业职工喷漆作业的劳动保护,实现职业危害的预防控制。     

华能汕头电厂煤场自动喷雾防尘系统的研制

通过采用废水综合利用技术和远射程喷雾降尘技术,研制并应用计算机自动控制系统,智能控制整个煤场的喷洒降尘过程,可以有效防治电厂煤场的扬尘,取得较大的环境效益和经济效益。该综合技术属国内首创。