Study On The Corrosion Resistance And The Property Of Coke Formation Inhibition Of The Electroless Coating

In recent years, many studies were carried out to develop the electroless coatings for numerous interests such as uniform thickness, high hardness, good corrosion resistance, easy operation. In this paper, two kinds of electroless coatings were prepared on the surface of carbon steel. The mixed organic acids corrosion resistance and the erosion-corrosion resistance of the electroless coating were studied by whole-soaking corrosion tests and slurry erosion tests combining SEM and electrochemical testing method; By improving the pretreatment process, Ni-W-P electroless coating was prepared on the surface of15CrMo sample and the performance of coke formation inhibition was studied. The results show:(1) Corrosion resistance of the two kinds of coatings are both better than stainless steel and carbon steel in the normal temperature and boiled organic acids and the corrosion rate of carbon steel is much higher than the other three kinds of materials. Corrosion resistance of stainless steel deteriorated rapidly in the boiled test, the addition of W is the key factor which makes the corrosion resistance of Ni-P coating much better.(2) The two kinds of coatings have good erosion resistance in acidic slurry erosion environment and obviously less effect of interaction than stainless steel and carbon steel. The major performance of interaction is acceleration of wear by corrosion. The erosion-corrosion resistance in descending order is:Ni-W-P coating, Ni-P coating, stainless steel and carbon steel.(3) Ni-W-P coating can decrease surface roughness, surface free energy and boundary layer thickness. Lower surface free energy can make it difficult for the condensate to attach on coating surface to form coke. The property of coke formation inhibition of the coating can be greatly improved by heat treatment and the efficiency of the coke formation inhibition increased from44.2%to75.9%.