Anti-fouling And Corrosion Resistance Performance Of Chemical Plating Ni-P Alloy In A Simulated Geothermal Water Environment

The fouling and corrosion of geothermal system seriously affect the exploitation and utilization of geothermal resources. In this paper, chemical plating Ni-P alloy were prepared. Tests were done to achieve the fouling resistant curves and heart transfer performance curves of chemical plating Ni-P alloy tubes,316 stainless steel tubes and copper tubes in a simulated geothermal water environment. SEM, XRD and EDS tests were used to characterize the fouling products on the surface of three types of tubes. Full immersion corrosion and electrochemical tests were made to study the corrosion resistance performance of chemical plating Ni-P alloy,316 stainless steel, copper and 20# carbon steel in the same simulated geothermal water environment. The main results show are as follow,Firstly, immersion corrosion and electrochemistry tests were used to study and compare the anti-fouling and corrosion resistance performance of chemical plating Ni-P alloy,304 stainless steel, copper and 20# carbon steel. The chemical plating Ni-P alloy shows the smallest corrosion current density and the highest AC Impedance, thus showing the best corrosion resistance. And when the density of Cl- increased, the four kinds of materials all meet a significant decrease in corrosion resistance performance. The progressive corrosion rate at this time is respectively 0.00071 mm·a-1,0.00144 mm·a-1,0.08523 mm·a-1,0.9661 mm·a-1.Secondly, tests have been done to achieve the fouling resistant curves and heat transfer performance curves of chemical plating Ni-P alloy tubes,316 stainless steel tubes and copper tubes under convective heat transfer. The experimental results show that Ni-P alloy significantly increase the duration of induction time, and it has a lower fouling rate and the asymptotic fouling resistance value is lower than the other two. For the Ni-P alloy tubes, the fouling is relatively thin and non-homogenous which could be washed away easily. The fouling behaviors of chemical plating Ni-P alloy tubes were also examined under different conditions of water hardness.