Low-temperature Electroless Nickel Plating Technology Based On SLA Prototype

In addition to entity verification test and assembly functions of the CAD design model,SLA prototype could also be used to trial production of the prototype and rapid tooling.In trial production of the prototype,SLA prototype needs layer nickel plating for surface decoration or protective sometimes;some rapid tooling process which based on SLA prototype also need layer nickel plating to conductive or direct manufacturing such as electrode.Therefore,electroless nickel plating on the surface of the SLA prototype has great research value and prospects.In this paper,the composition and the function of the electroless nickel plating solution.At this basis,Ni-P alloy coating was successfully plated based on SLA prototype.The appearance,adhesion,hardness and corrosion resistance of the coating were tested by weighting,as well as the cross-sectional method to calculate the average thickness of sedimentary layers.And the samples were detected and analyzed by SEM,EPMA and X-Ray diffraction.The coarsened quality of SLA will decide the cohesion between Ni-P coating and substrate.In this paper,through a great deal of experiments,author found a kind of coarsened prescription suitable for SLA prototyping,forming many holes and troughs on its surface.In order to obtain reasonable processing parameter of electroless nickel plating,the influences of the concentration of NiSO₄,NaH₂PO₂, complex agent,pH value,temperature and stirring speed on the deposition rate,the content of P were studied.It was found that the concentration of lord salt NiSO₄ varied form 30g/L to 35g/L,the concentration of reductants NaH₂PO₂ varied form 30g/L to 35g/L,the concentration of complex agent C₃H₅NaO₃ varied form 20g/L to 25g/L,the concentration of complex agent N(CH₂CH₂OH)₃ varied form 10ml/L to 15ml/L,the concentration of buffer NH₄Cl was 30g/L,pH value form 9 to 10,and the reaction temperature varied form 40℃～45℃.Observing the appearance of the Ni-P coating,you will find it is very smooth, compact and has metal luster without small hole,grey dot,and curly skin.The content of phosphorus was not more than 3%of the coating for microcrystalline structure.The different samples which were deposited during times were analyzed by SEM and X-ray diffraction to explain the depositing process of electroless nickel plating.The results of adhesion and corrosion resistance experiment show that it can meet the requirement for use.Electroless nickel plating state hardness HV650.