Tantalum is widely used in aerospace, electronics, automobile, military, chemical industry and other fields because of its excellent properties such as high melting point, strong corrosion resistance and good electrical conductivity. The hardness of tantalum is moderate and its coefficient of thermal expansion is small. In the field of superalloy, tantalum can also be used as a diffusion barrier for the interdiffusion of elements between coating and matrix. At present, the methods of tantalum film plating mainly include: molten salt electroplating, chemical vapor deposition, magnetron sputtering, ion beam sputtering, ion beam assisted deposition, DC diode sputtering, etc. The metal tantalum or tantalum coating has very high corrosion resistance, and it does not react with hydrochloric acid, concentrated nitric acid and "aqua regia" under both hot and cold conditions. Therefore, the surface activation of tantalum is very difficult, resulting in poor adhesion of electroplating coating on tantalum. Access to relevant information and found that on the metal tantalum or tantalum coating electroplated
nickel need activation treatment on the surface, the study found that tantalum in oxalic acid, HCl and HF acid activation effects are not obvious, and add a few drops of concentrated nitric acid in HF acid solution, the activation effect is improved obviously, but have certain risk, HNO3 and HF and tantalum in the violent reaction, it has much limitation. The invention provides a new surface activation process of tantalum or tantalum coating, and through this process and combined with heat treatment, electroplated nickel coating with high bonding strength with matrix can be prepared.
