Preparation Of Copper-based Composite Filler Used In Conductive Rubber

With the development of modern high-tech, electromagnetic wave is a growingproblem caused by electromagnetic interference (EMI) and electromagneticcompatibility (EMC). Conductive rubber is not only used as seal material and buffer,but also plays the role of electromagnetic shielding. At the same time, it ensures theinformation security and personal safety. Therefore, conductive rubber is more andmore widely used in electronic instalments, equipment and other fields. At present,silver, gold and other precious metals are certain limited in application because oftheir high price. Copper powder is low prices and has good conductivity, so thecopper-based composite ifller has the majority of the practical application of market.In this paper, it was mainly studied that the surface chemical modificationtechnology of silver plate and nickel plate on the surface of dendritic copper powder,and obtain good composite copper powder It found that the pH value of platingsolution was the critical process parameter Reasonably controlling the pH value andits adjustment mode made precipitation rate of the plated metal to match thedeposition rate, so as to obtain the homogeneous and continuous metal plating layerwith less impurity element. Ammonium ion could activate the copper powder andcomplex the metal ions to improve the stability of the bath and reduce bath turbidityand pasting phenomenon. NaOH concentration was the key parameter for preparationof large amount copper powder. Electroless plating reaction made the pH value ofplating solutions decline. Adding NaOH solution could stabilize the pH value andachieve stable production of copper-based composite powderThrough the studies of plating morphology, components, electrical conductivityand oxidation resistance of the composite powder evaluated the quality of the powderproperties. The stability of the process was evaluated based on conversion rate ofplated metal and extraction rate, optimize the process for obtaining good performanceof copper-based composite powder Obtain silver clad copper powder with stabilitypreparation200g powder copper. Conversion rate of Ag plating process AC-18was100%, Conversion rate of Ag plating process AC-22was (97士.71.29)%. Obtainstabilized preparation500g copper nickel clad copper powder, extraction rate ofpowder of the process NC-30was (101.8士0.5)%. Extraction rate of powder of theprocess NC-40was (109.9士0.6)%.Nickel clad copper powder combines nickel magnetic property and copper good electrical conductivity, and low cost. Nickel clad copper powder can achieve similar shielding effectiveness at the same dosage. At220phr, the shielding effectiveness of AC-18conductive rubber and NC-30conductive rubber achieve above60dB in100k Hz～1.5G Hz.