Electroless Ni-P deposition on magnesium alloy from a sulfate bath
Tóm tắt
A technology for electroless Ni-P deposition on AZ91D from a low cost plating bath containing sulfate nickel was proposed. The seal pretreatment was employed before the electroless Ni-P deposition for the sake of occluding the micro holes of the cast magnesium alloy and interdicting the bubble formation in the Ni-P coating during plating process. And pickling pretreatment can provide a better adhesion between the Ni-P deposition and AZ91D substrate. The deposition speed of the Ni-P coating is 29 μm/h. The technology is employed to AZ91D magnesium alloy automobile parts and can provide high hardness and high wear-resistant. The weight losses of Ni-P plated and heat-treated Ni-P plated magnesium alloy specimen are only about 1/6 and 1/10 that of bare magnesium alloy specimen after 10 min abrasion wear, respectively. The hardness of the electroless Ni-P plated brake pedal support brackets is 674.1 VHN and 935.7 VHN after 2 hours heat treatments at 180 °. The adhesion of Ni-P coatings on magnesium alloy substrates meets the demands of ISO Standards 2819. The technology is environment friendly and cannot cause hazard to environment because of absence of chromate in the whole process.
Tài liệu tham khảo
S Ignat, P Sallamand, D Grevey, et al. Magnesium Alloys Laser (Nd:YAG) Cladding and Alloying with Side Injection of Aluminum Powder[J]. Appl. Surf. Sci., 2004, 225(1–4): 124–134
Z G Chen, Z Q Zhang, H K Yi. Effects of Trace Silver and Magnesium on the Microstructure and Mechanical Properties of Al-Cu-Li Alloys[J]. J. Wuhan University of Technology-Mater. Sci. Ed., 2005, 20(1): 9–12
L N Hu, X F Bian, Y F Duan. Hydrogen Content and Porosity Behavior of Hypereutectic Aluminum-silicon Alloy with Phosphorus[J]. J. Wuhan University of Technology-Mater. Sci. Ed., 2004, 19(4): 65–68
H Watari, K Davey, M T Rasgado, et al. Semi-solid Manufacturing Process of Magnesium Alloys by Twinroll Casting[J]. J. Mater. Process. Technol., 2004, 155–156: 1 662–1 667
Q Shen, L M Zhang, H Tan, et al. Preparation of Mg-Ti System Alloy and FGM with Density Gradient by Spark Plasma Sintering Technique[J]. J. Wuhan University of Technology-Mater. Sci. Ed., 2004, 19(1): 58–60
Z H Xiao, J R Luo, S S Wu, et al. Performance of Semi-solid Slurry Produced by Twin-screw Stirring Mixer and Rheodiecasting Process of AZ91D Alloy[J]. J. Wuhan University of Technology-Mater. Sci. Ed., 2004, 19(3): 81–85
D Hawke, D L Albright. A Phosphate-Permanganate Conversion Coating for Magnesium[J]. Met. Finish., 1995, 93(10): 34–38
H Umehara, M Takaya, S Terauchi. Chrome-free Surface Treatments for Magnesium Alloy[J]. Surf. Coat. Technol., 2003, 169–170: 666–669
Z C Kwo, S S Teng. Conversion-coating Treatment for Magnesium Alloys by a Permanganate-Phosphate Solution[J]. Mater. Chem. Phys., 2003, 80(1): 191–200
E H Han, W Q Zhou, D Y Shan, et al. Corrosion and Protection of Magnesium Alloy AZ31D by a New Conversion Coating[J]. Mater. Sci. Forum, 2003, 419(4): 879–883
L Kouisni, M Azzi, M Zertoubi. Phosphate Coatings on Magnesium Alloy AM60 Part 1: Study of the Formation and the Growth of Zinc Phosphate Films[J]. Surf. Coat. Technol., 2004, 185(1): 58–67
L Kouisni, M Azzi, F Dalard, et al. Phosphate Coatings on Magnesium Alloy AM60 Part 2: Electrochemical Behavior in Borate Buffer Solution[J]. Surf. Coat. Technol., 2005, 192(2–3): 239–246
L Y Niu, Z H Jiang, G Y Li, et al. A Study and App1ication of Zinc Phosphate Coating on AZ91D Magnesium Alloy[J]. Surf. Coat. Technol., 2006,200(9):3 021–3 026
C D Gu, J S Lian, G Y Li, et al. Electroless Ni-P Plating on AZ91D Magnesium Alloy from a Sulfate Solution[J]. J. Alloy. Compd., 2005, 391: 104–109
C D Gu, J S Lian, G Y Li, et al. High Corrosion-resistant Ni-P/Ni/Ni-P Multilayer Coating on Steel[J]. Surf. Coat. Technol., 2005, 197(1): 61–67
K Sharma, M R Suresh, H Bhojraj, et al. Electroless Nickel Plating on Magnesium Alloy[J]. Met. Finish., 1998, 96(3): 10–18
H W Huo, Y Li and F H Wang. Corrosion of AZ91D Magnesium Alloy with a Chemical Conversion Coating and Electroless Nickel Layer[J]. Corros. Sci., 2004, 46(6): 1 467–1 477
R Ambat and W Zhou. Electroless Nickel-Plating on AZ91D Magnesium Alloy: Effect of Substrate Microstructure and Deposition Parametersp[J]. Surf. Coat. Technol., 2004, 179(2–3): 124–134
ASTM Standards B733-1997. Standard Specification for Autocatalytic (Electroless) Nickel-Phosphorus Coatings on Metal [S], 1997
ISO Standards 2819-1980. Metallic Coatings on Metallic Substrates-Electrodeposited and Chemically Deposited Coatings-Review of Methods Available for Testing Adhesion[S], 1980
Z Abdel Hamid and M T Abou Elkhair. Development of Electroless Nickel-phosphorous Composite Deposits for Wear Resistance of 6061 Aluminum Alloy[J]. Mater. Lett., 2002, 57(3): 720–726