Effect of Pretreatment Process on the Adhesion and Corrosion Resistance of Nickel-Boron Coatings Deposited on 8620H Alloy Steel

Abstract

In this work, Ni-B coatings were electrodeposited on the 8620H steel substrates, the substrates were carried out with different pretreatment including without pretreatment, after sandblasting by glass sand and after sandblasting by emery powders. The results of scratch test indicated that the best adhesion strength of Ni-B coatings occurred at the 8620H steel substrates carried out with sandblasting by emery powders, the Ni-B coatings still did not be damaged when the load increase to 50 N. The icorr values of Ni-B coatings deposited on different pretreatment condition such as without pretreatment, after sandblasting by glass sand and after sandblasting by emery powders are approximately at 9.46×10 -6 , 8.62×10 -6 and 2.31×10 -6 A/dm 2 , respectively. All the samples carried out with a wear process at a load of 20 N, the icorr values of Ni-B coatings deposited on different conditions 1.96×10 -5 , 1.54×10 -5 and 6.72×10 -6 A/dm 2 , respectively. The results show that the Ni-B coatings deposited on the 8620H steel substrates carried out with sandblasting by emery powders has the best adhesion strength and corrosion resistance due to the Ni-B coatings did not be damaged during wear process.