Fabrication and Characterization of Nano Silver Powder Prepared by Spray Pyrolysis

Silver powder was fabricated by spray pyrolysis, using 2%-20% AgNO3 solution, 336-500 mL/h flux of AgNO3 solution, 0.28-0.32 MPa flux of carrier gas and in the 620-820 ℃ temperature range. The effects of furnace set temperature, concentration of AgNO3 aqueous solution, flux of AgNO3 aqueous solution as well as carrier gas on the morphology and particle size distribution of silver powder, were investigated. The experimental results showed that with the high concentration of AgNO3 aqueous solution, the average grain size of silver decreased with the increasing of furnace set temperature. But the gain size distribution was not homogenous, the discontinuous grain growth occurred. With the low concentration of AgNO3 aqueous solution, the higher furnace set temperature made the nano sliver grains sintered together to grow. Nano silver powder about 100 nm was fabricated by spray pyrolysis, using 2wt% AgNO3 solutions, 336 mL/h flux of AgNO3 aqueous solution, 0.32 MPa flux of carrier gas at 720 ℃ furnace set temperature.

PREPARATION OF SILVER POWDER FOR CONDUCTIVE PASTE

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Effect of Water Chestnut Powder on Gel Properties of Silver Carp Surimi

[Objectives]The effects of water chestnut powder on the gel properties and quality of silver carp surimi were investigated.[Methods]The surimi gel was prepared by adding 0%,1%,2%,3%,4%and 5%of water chestnut powder to the surimi of silver carp.The gel properties,water-holding capacity,cooking loss,whiteness value,puncture and texture profile analysis(TPA)indexes of surimi products were determined to assess the effects of adding different amounts of water chestnut powder on surimi gel.[Results]The results showed that the gel strength,breaking force and depression distance of surimi products increased first and then decreased with the increase of the addition of water chestnut powder.Compared with the control group,the hardness and chewiness of surimi gel in TPA could be significantly improved by adding water chestnut powder.When the addition of water chestnut powder was 2%,the maximum water-holding capacity was 83.68%;the cooking loss rate was the lowest;and the whiteness value was the highest.Adding 2%of water chestnut powder could significantly improve the gel properties of silver carp surimi and obtain a good gel product.[Conclusions]This study provides a scientific basis for the effective utilization of water chestnut resources and the development of new fish surimi products.

Preparation of titanium dioxide/silver sulfate powder and its antibacterial activity

Antibacterial powders of titanium dioxide/silver sulfate were produced by heat-treatment of the metatitanic acid, as precursor, into which the silver nitrate was added. The influences of heating temperature on the structure and composition of the product were investigated through XRD and SEM. The results show that the powder is spherical in the phase of TiO2-Ag2SO4. The granularity of the particles increases from 10.7nm to 28.7nm with the temperature of heat-treatment increasing from 300℃ to 800℃. The antibacterial activity of the powder was judged in the way of the minimum inhibitory contents （MiCs）. When the content of silver sulfate is less than 2%, the photocatalysis of titanium dioxide and silver ions cooperate to kill bacteria. And the MiCs decrease and keep around 1.0×10 -41.5×10 -4 constantly with the increase of silver content. Furthermore, the MiCs decrease with the increase of temperature of heat-treatment when the temperature is lower than 500℃. But when the temperature is beyond 600℃ the MiCs increase quickly, which shows the inferior antibacterial performance.

Study on Properties of Silver Powder for Maki-e

Maki-e is a traditional Japanese decorative technique that uses the natural lacquer Urushi and metal powders. In 2014, there exist only two companies that manufacture silver powder for the purpose of Maki-e, and this study focuses on comparing the powders manufactured by them. Gloss and color of each silver powder were measured after Maki-e decoration was finished, and EDS (energy-dispersive X-ray spectroscopy) was used to determine the differences in their chemical composition. In addition, to verify the effect of polishing, residual gloss after sulfuration and polishing was measured. The study revealed that the shapes of the silver powders (Maru-fun, No. 1) manufactured by the two companies are different and it affects the occupancy rate of Urushi and powder, which in turn affects their gloss and color. Wakou silver has a very strong resistance to sulfuration;however, owing to its Pd content, its chroma is much lower than that of other powders. It was shown that sulfuration on powder surface can be removed by polishing irrespective of the shape and chemical composition ratio of the particles.

Effects of Supplemental Amount of Tuanfeng Lotus Seed Powder on Quality of Silver Carp Surimi Products

[Objectives]This study was conducted to improve the gel properties of freshwater surimi and its products. [Methods] Tuanfeng lotus seed powder was added to frozen silver carp, and the relationship between the addiamount of Tuanfeng lotus seed powder(1%, 2%, 3%, 4% and 5%) and the quality of surimi products was studied, so as to improve the quality of surimi products. [Results] The water holding capacity(86.71%±0.36%), hardness(3 566.64±51.15) g, chewiness(2 697.16±15.81) g and gel strength(692.54±23.19) of surimi products increased to the maximums when the addition amount of lotus seed powder was 3%. Meanwhile, the cooking loss rate was reduced to the minimum(13.00%±0.17%), and the sensory quality was the best, although the whiteness of surimi products decreased slightly with the increase of Tuanfeng lotus seed powder. Therefore, the quality of silver carp surimi products could be improved obviously when the dosage of Tuanfeng lotus seed powder was 3%. [Conclusions] This study provides more new ideas for improving the quality of silver carp surimi products, and simultaneously makes the development of lotus seed food more diversified.

银粉对硅异质结太阳电池用低温银浆的影响综述

银浆是硅异质结太阳电池的重要材料,更低的体积电阻率和接触电阻、良好的附着力、优良的细线印刷性能及组件栅线抗腐蚀老化是其不断改进的方向。作为导电相,银粉的性能和含量对银浆有着至关重要的影响。该文基于低温固化银浆导电机理以及SHJ电池对银浆性能的追求,综述了银粉的振实密度、形貌、粒径、表面处理剂及其与有机物的适配。进一步探讨了纳米银粉和银包铜粉在SHJ太阳电池用低温银浆中的应用。

非水溶液体系中晶种法制备球形银纳米颗粒

以丙三醇作溶剂,硝酸银为原料,聚乙烯吡咯烷酮(PVP)为分散剂,硼氢化钠为还原剂制备了银纳米晶种;以此银纳米粒子作为初级晶种,以丙三醇作溶剂和还原剂,通过升温提高丙三醇的还原性制备银纳米颗粒。研究分散剂种类、生长液银浓度、晶种加入量对银粉的影响,采用X射线粉末衍射仪(XRD)、场发射扫描电子显微镜(FE-SEM)、透射电子显微镜(TEM)对制备产物的结构、物相、形貌进行表征。结果表明,通过改变条件可以制备出分散性良好、粒径均匀的70nm左右的球形银粉。

枸杞粉对白鲢鱼糜凝胶品质的影响

该研究以冷冻白鲢鱼糜为实验原料,向其中添加枸杞粉(wolfberry powder,WP),分析不同添加量[0.25%、0.5%、0.75%、1%、1.5%(质量分数)]的WP对白鲢鱼糜凝胶持水性、蒸煮损失率、白度值、水分分布、凝胶特性、微观结构、感官评价及气味特征的影响。结果表明,随着WP含量的增加,鱼糜凝胶的持水性、硬度、咀嚼性和凝胶强度都表现出先增大后减小的趋势,当WP的添加量为0.5%时达到最大,分别为78.55%、(2716.77±75.76)g、(2185.15±32.46)g和1087 g·cm;而蒸煮损失率则表现出先减小后增大的趋势,在0.5%的添加量时,蒸煮损失率最小,为7.49%。在鱼糜中加入WP后,可以减少鱼糜凝胶中自由水的比例,增加不易流动水的比例,使鱼糜凝胶保留更多水分,且当WP在最适添加量0.5%时,鱼糜凝胶中只检测到结合水和不易流动水,未检测到自由水。适量WP的添加会增强鱼糜凝胶的网络结构,使其变得更加致密均匀。WP的添加会减小鱼糜凝胶的白度值和色泽评分,但在最适添加量0.5%时,其颜色总体可接受。此外,感官评价和电子鼻分析结果表明,当WP在最适添加量0.5%时,可以显著改善鱼糜凝胶的风味品质。研究结果可为生产高品质的鱼糜产品提供理论依据。

高功率半导体用纳米银焊膏的研究现状

第3代半导体作为核心部件,使得更紧凑、高频率、高功率的电子器件在射频和微波电子、能源转换与储存、雷达和通信等领域展现出广泛的应用潜力。然而,高性能电子器件对其封装材料的导电性、导热性以及连接处的机械性能提出了更为严格的要求。纳米银焊膏因其卓越的低温烧结性能和在高温环境下的出色表现引起了广泛关注。然而,国内银粉和银焊膏产品的质量相对较低,且研发过程缺乏理论指导,必须依赖进口材料。基于高功率半导体用纳米银焊膏,综述了通过液相化学还原法合成纳米银粉的研究进展,以及纳米银焊膏的烧结机理、影响其性能的因素和控制方法,有望为国内纳米银焊膏的研发和生产提供有益的指导和支持。

臭氧+MVR+脱氨+MBR工艺对银粉加工废水的处理

银粉加工废水具有高盐、高COD_(Cr)和高氨氮等特点,对环境污染大,且处理难度大。针对某单位的银粉加工废水,采用臭氧催化氧化+MVR蒸发+氨氮吹脱+MBR生化组合工艺对其原有工艺进行改造。结果显示,废水出水水质COD为17 mg/L、氨氮为0.72 mg/L、TDS为601 mg/L、总氮为6.55 mg/L、pH为6~9,出水达到《四川省岷江、沱江流域水污染物排放标准》DB 51/2311-2016水质标准。采用臭氧催化氧化替代芬顿氧化,直接运行费用为71.12元/m~3,比芬顿单元降低157.88元/m~3,危险废物减少791.29 kg/d。该方法具有显著的环境效益和经济效益。

超声波法制备银合金粉末的研究

光谱分析用标准样品在标准样品的发展中逐渐占主导地位,贵金属标准样品因成分偏析等因素使其标准样品难以制备。粉末冶金技术可制备出成分均匀、晶粒细小的合金,优质粉末的制备可为标准样品的制备提供原料基础。本文借助超声波清洗机对银合金进行振动,探究能否制得银合金粉末,并通过测试分析结果探究该方法能否达到细化晶粒的效果。实验分别从形态、粒径与晶粒、化学成分三个方面来进行对比说明,通过使用偏光显微镜、扫描电镜及能谱仪对银合金及银合金粉末进行观察测试,X射线荧光光谱仪对化学成分结果进行验证。使用超声波振动银合金制备银合金粉末,作为一种新型的制备银合金粉末的方法,超声功率达到600 W时,可以制备出平均粒径为9.54μm的粉末,其中超过70%的银合金粉末小于10μm。银合金的平均晶粒尺寸为22.5μm,说明超声波振动银合金具备细化晶粒的条件,结合形态和成分测试观察结果,说明通过制备粉末的方式既可以细化晶粒,也可以改善组织均匀性。

一种无溶剂型电子封装用导电胶的研制

为了解决导电胶黏剂因综合性能不足而导致大规模应用的受限,本文以酚醛环氧、多官能环氧为导电胶树脂基体,选用了4,4′-二氨基二苯砜(DDS)作为固化剂,片状银粉作为导电填料,通过调节银粉和固化剂的用量,制备了有良好流变性、导电性、力学性能的导电胶。通过分析测试,得到导电胶的黏度为32 800 mPa·s,触变指数为4.0,体积电阻率为4.34×10^(-4)Ω·cm,剪切强度为17 MPa,热导率为3.96 W/(m·K),Cl^(-)、Na^(+)和K^(+)分别仅为6.79×10^(-5)、6.31×10^(-5)和<10^(-5)。该导电胶综合性能优异,可应用于电子元器件及其他导电导热功能性材料的粘接。

响应面法优化板栗鱼肠的加工工艺

以信阳本地产南湾鲢鱼和板栗粉为主要原料,并添加大豆分离蛋白、卡拉胶等辅料制成鱼肠。以鱼肠的色泽、持水性、凝胶强度、TPA、感官评分为指标,研究了鱼糜/板栗粉质量比、大豆分离蛋白、卡拉胶、食盐、料酒的添加量对鱼肠品质的影响。得到鱼肠最佳制作配方:鱼糜/板栗粉质量比12∶1、大豆分离蛋白、卡拉胶、料酒、食盐质量分数为6%、0.8%、4%,2%。所得鱼肠平均白度78.2%、感官评分95.6、持水率87.7%、凝胶强度3761.2 g·mm。所得鱼肠肉质细腻嫩滑,具有光泽,肉味浓郁伴有板栗清香。本研究为新型鱼肠产品的研发提供一定的理论依据和参考,有利于丰富市售鱼糜制品种类。

压电陶瓷用银浆的研制

目前,附着力低是压电陶瓷银浆存在的主要问题。笔者研究了玻璃化学成分、银粉对压电陶瓷银浆性能的影响,其结果表明,在玻璃原材料里加入适量的二氧化钛,是压电陶瓷银浆附着力提高的关键措施。优化配方使用混合银粉,选用合适配方的玻璃粉,所得银浆料的印刷性能、方阻、附着力、与焊料的润湿性及耐焊性等各项指标均符合要求。

高电流密度银电解新型药剂的应用及工艺优化研究

针对高电流密度银电解精炼工艺中容易出现的酸度高、电解液寿命短、银粉晶型不合理(海绵体)、附属设备氧化腐蚀快、高温烧槽等问题,开发出了一种新型银电解药剂A与硝酸混合使用。通过生产实践,结果表明:在新型电解药剂A添加量在100 g/批时,银锭主品位达到99.997%。

优化银电解电银粉洗涤工艺

某冶炼厂银电解电银粉洗涤、烘干工序采用人工洗涤和电热烘箱烘干方式进行生产,易出现能耗高、耗时长、劳动强度大等问题。针对出现的问题,自主研发了一套新型银粉洗涤-烘干装置,有效降低了能源消耗,减少了生产耗时,取得了较好的使用效果。

不同类型搅拌桨制备银粉的实验研究

利用双层反应釜进行液相还原法制备银粉颗粒,以硝酸银为银源,抗坏血酸为还原剂,研究不同转速和搅拌桨类型对银粉特性的影响。利用扫描电子显微镜、粒度分析仪、X射线衍射仪对银粉的形貌、粒度及晶体结构进行详细的表征。结果表明,反应器内的流场对银粉的形貌和粒径的改善效果显著。用0.5 mol/L硝酸银溶液、0.6 mol/L的抗坏血酸溶液及PVP为原料,在四叶桨400 r/min的搅拌下,制备出结晶性良好、平均粒径在352 nm的球形银粉。

片状银粉制备方法的研究进展

片状银粉作为银浆的重要组成部分,其制备方法得到了广泛研究。阐述了片状银粉制备方法,包括机械球磨法、光诱导法和模板法等3种方法的工艺原理,分析了各方法的优缺点,并对机械球磨法和模板法的研究方向进行了展望,以期为片状银粉的制备提供参考。

太阳能电池导电银浆研究进展

大力推进新能源的使用有助于我国早日实现“双碳”目标,太阳能电池能够将太阳能直接转化为电能,是最早将新能源进行利用的设备之一。具有优良导电性和印刷性的导电银浆成为太阳能电池的首选电极材料,其主要由银粉、玻璃粉、有机载体及优化性能的其他添加剂等组成,其性能直接影响着太阳能电池的效率。文章重点介绍了太阳能电池导电银浆的组成以及制备方法,总结了目前银浆市场的发展情况以及导电银浆未来的发展趋势,提出了我国导电银浆行业的问题及相应建议,希望对国产银浆的发展具有一定的指导。