(1. 清華大學(xué) 核能與新能源技術(shù)研究院，北京 100084；
2. 中南大學(xué) 粉末冶金國家重點(diǎn)實(shí)驗(yàn)室，410082)
摘 要: 在以抗壞血酸為還原劑、銀氨配合物為前驅(qū)體、PVP為保護(hù)劑及表面活性劑為分散劑的液相化學(xué)還原體系中制備超細(xì)銀粉，研究陽離子、陰離子和非離子表面活性劑在銀粉制備過程中的防團(tuán)聚作用和分散作用，并采用掃描電鏡(SEM)和X射線衍射等對還原產(chǎn)物進(jìn)行形貌觀察和結(jié)構(gòu)表征。結(jié)果表明：表面活性劑的種類對制備樣品的純度、分散性和顆粒大小有著重要的影響，其中陽離子表面活性劑和陰離子表面活性劑的分散效果不明顯，非離子表面活性劑的分散效果最好。對吐溫(TW)系列分散劑的研究表明：TW相對分子質(zhì)量的大小對銀粉顆粒的分散效果、形貌和大小也有顯著影響；采用TW80分散劑可制備出高分散、窄粒級的超細(xì)銀粉。
關(guān)鍵字: 超細(xì)銀粉；表面活性劑；抗團(tuán)聚；分散
ultrafine silver powder
（1. Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China;
2. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract: The preparation of ultrafine silver powder was investigated by reducing Ag(NH3)2+ with ascorbic acid in the presence of poly-(vinylpyrrolidone) (PVP) as protective agent and surfactants as dispersant. The effects of cation, anion, and non-ion surfactants on aggregation-proof and dispersion of silver particles in the preparing silver powder were investigated, and the pattern and phase of reducing products were also characterized by scanning electron microscopy (SEM) and X-ray diffractometry (XRD). The results show that the surfactant species impact apparently on the purity, dispersion degree and particle size of the reducing sample. The non-ion surfactants can improve the dissemination of ultrafine silver particles, but both the dispersive effects of cation and anion surfactants are unapparent. Moreover, the results of reducing experiments with a series of TW surfactants show that the relative molecular mass of TW affects the dissemination, pattern and size of silver particles, and the well-dispersed ultrafine silver powder with narrow size distribution can be prepared in the presence of TW 80 surfactant.
Key words: ultrafine silver powder; surfactant; aggregation-proof; dispersion
