Electromagnetic Shielding Nickel Package Copper Powder Preparation Of The Research And Application Of New Technology

With the rapid development of electronic industries, the electromagnetism jam has become a new public harm. First, the electromagnetism radiation will effect human' s health and jam the electron instruments and equipments around, making their work program become turbulence and leading to error action;Another, electromagnetism radiation probably leak to information, thus the computer and other instruments can' t get the safe guarantee. To solve the problem of electromagnetic pollution, according to electromagnetic shielding principle, the author has made up a stuffing of conductive lacquer-Ni-Cu composite powder. This stuffing can use as an powder of shielding the electromagnetism.This paper adopted two methods to made-up the Ni-Cu composite powder, including the acid system and the neutral system .A great number of experiment were performed to get optimal technological parameters as follows: The acid: NiSO₄·6H₂O 25-35 g/L,NaH₂P0₂ ? H₂0 27³2g/L, stuffing one 22-25ml/L, stuffing two 10-15g/L, PH value 5-8, T 85-95°C, coating time l-2h;the neutral: NiS0₄ ? 6H₂0 27-36g/L, NaH₂P0₂ ? H₂0 30³5g/L, stuffing three 30³6g/L, stuffing four 10-15g/L, PH value 7⁸, T 60-80℃, coating time 0. 5-lh. Changing the major technical parameter, such as the initial concentration of Ni²⁺ the initial concentration of reducing agent, PH value, plating temperature , heat-retaining period and addition amount of copper powder, those can effect the deposit quantity of Ni²⁺ and the deposit rate. Both the two method can made-up the nickel covered copper powder, the nickel content from 25% to 70%, the phosphorus content from l%-7%. The nickel and phosphorus content can control in some range through adjusting the content of every component in the solution and changing the correlative technical parameter, and the impurity content in the composite powder is lower, commonly the oxygen content is from 0. 07%-0. 35%, although the powder have been placed a long time, the oxygen content are lower 0. 7%. SEM photosreveal that the nickel coated copper powder has satisfactory morphology and flaky degree, it has good conductivity, the resistance value of this powder is from 2. 3 to 47 mQ. So the nickel coated Copper powder' s integrate performance are excellent.Both the two system' s reducing agent are NaH2P02 ? H20, the difference is stuffing. The neutral system' s coating temperature is lower, and the neutral system adopted ultrasonic as the assistant instrument which can accelerate the deposit rate. A Ni-based composite shielding coating has been prepared, the nickel coated Copper powder are used as composite fillers, and acrylic resin as binder. It' s resistance is 3. 3 Q, the conductivity are good and the physic property , chemical property measure up to the correlative standard.