摘要：对粉煤灰微珠进行热碱液活化,以葡萄糖为还原剂,通过向碱性溶液中缓慢滴入AgNO₃溶液来制备镀银复合粉体;采用扫描电子显微镜、X射线能量色散谱和X射线衍射进行形貌观察及成分分析,并探讨热碱活化化学镀银机理。结果表明:银镀层为均匀致密的纳米晶;镀银复合粉体的电阻率达到0.05Ω·cm;热碱活化化学镀银机理为强碱与SiO2和Al2O3发生强烈作用,在粉煤灰微珠表面生成大量羟基基团,其亲核性对银铵阳离子产生极性吸引并在葡萄糖的还原作用下还原为单质银。

关键词：粉煤灰微珠；热碱活化；化学镀银；机理

Abstract： The composite powders of fly ash cenospheres plated by silver were prepared by slowly adding the solution of AgNO3 into alkaline solution with D-glucose as reducing agent after hot alkali’s activation. The morphology and composition of the silver-coated fly ash cenospheres composite powders were observed and analyzed by SEM， EDS and XRD. The mechanism of electroless silver plating on fly ash with thermo-alkaline activation was studied. The results show that the nano-crystalline silver plating is even and compact. The resistivity of the composite particles can reach 0.05 Ω·cm. The mechanism of electroless silver plating on fly ash with thermo-alkaline activation is as follows. A large number of hydroxyl groups are generated on the surface of fly ash cenospheres due to powerful reaction of alkali with SiO₂ and Al2O3， then the nucleophilic of hydroxyl groups promotes polarity attraction on silver ammonium cation， so the silver is reduced by reduction reaction of D-glucose. 

Keywords: fly ash cenospheres； thermo-alkaline activation； electroless silver plating； mechanism