|
The test by means of chemical copper plating in the surface of the Si powder to obtain a uniform Cu-Si composite powders, preparing a good performance of Cu-Si electronic packaging metal matrix composite material for the target. The composite powder of the metal base substrate and enhance the degree of phase uniformly mixed, to reduce the residual stress of the interface to improve the combination of state-phase composite material composites. The test is prepared coated uniformly good performance Cu-Si composite powders, the first of the preliminary process of Cu-Si composite powder prepared by electroless plating. Trial found that when the bath the only copper salt (CuSO4 5H2O), reducing agent (HCHO), complexing agents (EDTA · 2Na and Na2C4H4O6) and Si powder coarsening can successfully Preparation of Cu-Si composite powder ; while the copper salt and the concentration of HCHO and a complexing agent to change multiples of the same, the Cu content of the type Si-Cu composite powders can be prepared, and a desired type of copper content of the composite powders prepared during the preparation of this composite material ready; roughening of the Si powder, dropping adding a reducing agent HCHO can be prepared Cu-Si powder coated evenly and completely. Then, by orthogonal design can get, electroless plating Cu-Si composite powder prepared the better preparation process for the HCHO / Cu = 6, complexing agent / Cu = 2, EDTA / complexing agent = 2/5, temperature = 60 ° C, i.e. Cu2 = 0.05 mol / L, the optimum plating bath formulations and conditions: CuSO4 · 5H2O under = 30g / L, HCHO = 72.0ml / L EDTA · 2Na = 35.735g / L, Na2C4H4O6 = 40.640g / L, temperature = 60 ° C, pH value of about 12. The test plating process conditions were studied with the electroless copper plating bath composition. The results are as follows: (1) the pH value is high for conducive to the conduct of the electroless plating reaction, and to shorten the reaction time, but is not conducive to uniform plating; lower pH values ??help to improve the quality of the coating, but low pH value causes the reaction time becomes too long. (2) With the increase of the concentration of formaldehyde, the reaction time is shortened dramatically, but more than a certain concentration, the formaldehyde concentration on the reaction time is no longer evident; concentration of formaldehyde is also a necessary condition for good plating results. (3) temperature increased, help to improve the electroless plating reaction speed, shorten the time required for chemical plating; but the temperature should not be too high, too high a temperature even reduce the stability of the bath, but also to get the elemental metal powder containing copper powder coated uniformly poor. (4), CuSO4 · 5H2O under = 30g / L EDTA · 2Na = 35.735g / L, Na2C4H4O6 = 40.640g / L, HCHO = 60-72ml / L, temperature = 60 ° C, pH = 12-12.5 loading amount of 1.5 g/100ml in a short period of time, to prepare a good, uniform coated composite powders of Cu-Si. The test section of the prepared composite powders was observed. The results are as follows: powder prepared Cu-Si composite powder, coating thickness of 5.5; 4 thick Cu-Si coexistence layer composite powders, Si particles and the copper layer are linked closely together, prepared late Cu-Si composites favorable.
|