Studies On Electroless NI-P Plating On ABS Resin To Get An Ultra Black Surface

The black in the popular color is considered as mystery and dignity. The black material is a result of absorbing most of visible light. When the absorptivity of visible light is higher than 99%, the material is called ultra black material. There are two types of black materials: one kind of them absorbs visible light through electron transition to form black, such as nigrosine, anthraquinone black, and iron oxide black, the other kind such as carbon black reflects and absorbs visible light several times with its superficial porous effect to form black. All of the above have not been able to achieve ultra black. Because of special function, the ultra black material has a widespread application and a promising market. Therefore, it is a profound theoretical and practical significance to study on the preparation of ultra black material.In this paper, the process of making organic polymer ABS resin ultra black was investigated. A higher absorptivity could be reached by forming many porous structures in the surface of ABS resin through electroless Ni-P plating and etching. Because the porous structure could reflect and absorb visible light several times, the absorptivity is above 99.5%.An ultra black ABS resin could be obtained.Firstly, the influence of the concentration of sensitizing solution and activation solution on the electroless Ni-P plating of ABS resin was studied in this article. There was no catalyst centers in ABS resin which was the necessary condition of electroless nickel plating. The sensitizing and activation was able to form catalyst centers in the surface of ABS resin which made the electroless nickel plating possible. The optimal concentration of sensitizing solution and activation solution on the electroless Ni-P plating of ABS resin was confirmed by experiment.Secondly, the influence of the component and the process of electroless nickel plating fluid on the phosphorus content of coating and the speed of electroless nickel plating were studied. The experimental data showed that: Concentration of nickel sulphate and sodium hypophosphite, pH, temperature and so on will influence the speed of electroless nickel plating. Temperature is the most important one among those factors. The higher the temperature, the faster the speed of reaction. Phosphors content (P %) of coating decreased in acidic solution as Ni²⁺/H₂PO₂^- and pH value increased.Thirdly, the relationship of the reflection of the black surface with etching process and phosphorus content of the coating was also studied. The experiment proved that concentration of nitric acid, temperature and blackening time will affect the reflectivity of the surface to visible light. As the blackening time prolonged, the reflectivity of the black surface firstly reduced and then increased; when the coating was totally etched and the bottom color was revealed, the superficial reflectivity was moved up sharply The surface, which was obtained when the coating phosphorus content was 5.2%～7.1%, was lower than that was obtained when the phosphorus content was 9.7%～12.9%.Finally, According to the SEM photos, a surface with porous structure could be obtained by first electroless Ni-P plating then etching. It's showed that nickel content of the coating was reduced after etching by EDX spectra, and Ni-P alloy was more difficult to be etched than Ni. The reflectivity of this surface could be under 0.5% by color measuring and matching instrument Datacolor650 and Cary500, which was far lower than the black polyester fabric as well as the black woven cottons. The obtained surface which had the ultra black effect could achieve the purpose of preparing the ultra black material.