Study On Preparation Of Ni-Cu-P Matrix Electroless Plating And Treatment Of Electroless Plating Bath

In this paper,Ni-Cu-P was deposited by electroless plating.The effects of bath composition and operating condition on composition,microstructure,morphology, wear & friction and corrosion resistance of Ni-Cu-P were investigated.And the nano-TiO₂ particles were introduced into electroless plating bath based on electroless plating Ni-Cu-P coatings to make the nano-TiO₂ particles and,Ni,Cu,P matrix co-deposit to obtain nano-TiO₂ electroless composite coatings.The effects of bath composition and operating condition on nano-TiO₂ content in electroless composite coatings were researched.At the same time,microstructure,morphology and composition of Ni-Cu-P composite coatings were characterized by XRD,SEM and EDS techniques.The properties of composite coatings,such as Micro-hardness, wear resistance and corrosion resistance were investigated.Photocatalytic performance of nano-TiO₂ composite coatings was evaluated.Metal ions and phsphorus remove with comlexzation deposition oxidation heavery is used by oxidation-deposition methed to explore an effective technique for electroless waste concentration treatment in order to decrease environment pollution.The result shows that deposition rate of electroless Ni-Cu-P coating decreases with the increase of CuSO₄·5H₂O concentration in bath.Micro-hardness of Ni-Cu-P coating can reach the highest value with CuSO₄·5H₂O concentration 0.6g/L. Crystallization of Ni-Cu-P coating takes place after 400℃heat treatment.Ni-Cu-P coating after 400℃heat treatment takes on excellent micro-hardness and wear resistance.Wear resistance can reach the highest value with the CuSO₄·5H₂O concentration 0.6g/L.of Ni-Cu-P coating presents better wear resistance than Ni-P coating.N-Cu-P coating possesses of favorable corrosion resistance.E_corr moved positively first and than negatively with the increase of CuSO₄·5H₂O concentration in bath.I_corr of Ni-Cu-P electroless coating is the lowest with the CuSO₄·5H₂O concentration 0.4g/L.It is found from Salt-fog test that corrosion resistance of electroless coating which was introduced Cu is much better than Ni-P coating and 45# steel.Nano-TiO₂ content in Ni-Cu-P-nano-TiO₂ composite coatings increases in the first and then decreases with the increase of nano-TiO₂ concentration in electroless bath.Nano-TiO₂ content can reach 7.75wt%when nano-TiO₂ concentration in bath is 6g/L.The corrosion resistance of Ni-Cu-P-nano-TiO₂ composite coatings is much better than Ni-Cu-P coatings and Ni-P-nano-TiO₂ composite coatings.The photocatalytic performance of Ni-Cu-P-nano-TiO₂ composite coating under optimized preparation process is slightly worse than Ni-P-nano-TiO₂ composite coating uder the same condition.Nickel ions and copper ions remove rate under the treatment of electroless solution can reach 99.1wt%and 98.8wt%respectively with the addition of complexzation deposition oxidant H₂O₂ 600ml/L,complexzation deposition time, complexzation deposition temperature 40℃,deposition pH 12 and deposition time 4h.Deposition rate,micro-hardness and corrosion resistance of the coating which is prepared using recycling electroless solution are little different from the coating prepared using original elecrroless solution.However,various aspects performances of the coating prepared using waste solution are inferior to the two formers.Phosphorus remove rate can reach 99.97%with the addition of potassium chloride 80g/L,deposition pH 6.0 and Settlement time 4h.