Preparation method of ultrafine copper powder for chip multilayer ceramic capacitors

The invention discloses a preparation method of ultrafine copper powder for chip multilayer ceramic capacitors, belongs to the field of functional powder material technologies, and relates to a liquid phase reduction method for preparing ultrafine copper powder and a surface modification method. The method includes the technical steps that a copper sulphate solution and a sodium carbonate solution are mixed and react to prepare an ultrafine copper powder precursor, and a hydrazine hydrate is added to the mixture to reduce the ultrafine copper powder precursor. The primary material for preparing the ultrafine copper powder precursor is cheap, the prepared ultrafine copper powder precursor is stable and not prone to oxidation, and residual SO42- can be easily and thoroughly removed in a washing manner; and meanwhile, the prepared ultrafine copper powder is high in purity, spherical, narrow in particle size distribution, balanced and controllable in particle size, good in dispersity and excellent in conductive performance. The method includes the simple technical processes, reactions are moderate, operation is easy and convenient, and scale production is easy to realize.