Study Of The Surface Coating Preparation With Metallized Compound Powder And Its Effectiveness Of The Electromagnetic Shielding

The wide use of various electron devices generates increasing electromagnetic interference and electromagnetic radiation, which has aroused the world attention. With the electric and magneto-conductive compound powder preparation technology and electromagnetic shielding coated with the compound powder as the study target, electroless plating is preferred to design the Ni-Fe-Cu-P alloy plating with the polypropylene powder as the basic materials and on the basis of experimentations on Ni-Cu-P, Ni-Fe-Pa alloys and Cu plating coat. With the compound powder, two kinds of compound powder, coating and adhesive, are already prepared.The reaction of chemical plating is very powerful at the preliminary stage due to the strong powder surface, which generates great difficulty for the powdery chemical plating. Therefore, this thesis tries to explore the pH adjustment of powdery chemical plating and the technology of plating liquid supplementing. The experimental results show the stability of plating liquid and the continuous plating are well achieved. Deep study of the pre-plating process of the polypropylene powder and the plating technology has successfully resolved the problems in the pre-plating process and plating difficulties generated by the instability and the poor polypropylene hydrophilic character.Special efforts have been made to study the influence of chemical elements of plating coat on the compound powder electromagnetic shielding. Direct current resistance and AA7003 atomic absorbing spectrum device are applied to the test of direct current rate and the chemical elements of plating coat. According to GB3657-83 of the national standard and SJ20524-1995 of the electron industry standard, test and study have been carried out on the magneto-conductivity of the plating coat and the electromagnetic shielding effectiveness of the powder coat. The results indicate that the prepared powder coat enjoys high electromagnetic shielding effectiveness, 10-30dB, and also show the electromagnetic shielding effectiveness has close relation with the resistance rate, the magneto-conductivity and the chemical elements of the plating coat.