No abstract

In this study, various properties of NiP and NiP -PTFE coating fabricated by electroless process were investigated. These coatings were applied on aircraft-grade aluminum samples. The results showed that the addition of nano-PTFE particles decreases coating rate from 7.1 mm/h to 6.1 mm/h and hardness from 510 HV to 200 HV. Also by increasing the pH value, coating rate increases from 1 mm/h to 7 mm/h. Increasing the solution temperature from 75 C to 90 C also increases the hardness of coating from 125 HV to 210 HV. The results showed that the heat treatment at 300 C for 4 h increases the hardness up to 375 HV due to formation of Ni 3 P hard phase in NiP -PTFE coating. Addition of PTFE particles have improved tribological properties due to its lubricating effects and simultaneously, have reduced corrosion resistance compared to NiP coatings, so that the corrosion current for Al, NiP , and NiP -PTFE coatings is À880, À550, and À770 mA/cm 2 , respectively.