熱氧化處理對 Inconel 718合金的腐蝕與磨耗腐蝕行為影響研究

Abstract

The purpose of the present study is to evaluate the structure and mechanical properties of the electroplated Ni-P/Oxide composite coatings as well as their effect on the corrosion and wear-corrosion resistance of Inconel 718 alloy in 3.5 wt.% NaCl solution. The thermal oxidation process was performed on Inconel 718 surface with different temperature (600˚C、700˚C、950˚C) and holding time (1h、24h、48h、72h) to enhance the adhesive strength of these composite coatings on Inconel 718 alloy. The surface morphologies and element compositions of the composite coatings before and after all tests are analyzed by scanning electron microscopy (SEM) and X-ray energy dispersive analyzer (EDS). The surface hardness of the specimens was measured by a Vickers′ hardness tester. Electrochemical polarization measurements are performed for analyzing corrosion characteristics, and using the block-on-ring surface friction manner to evaluate the wear-corrosion behavior of these composite coatings in Hanks′ solution. The friction ring counterpart is made of a sintered Al2O3. Experimental results indicated that the anodizing and thermal oxidation treatment could enhance the electroplated Ni-P coating in addition to the electroplated Ni-P/oxide composite coatings. The hardness and wear–corrosion resistance of the electroplated Ni-P/oxide composite coating were improved significantly for Inconel 718 alloy. The thermal oxide treatment during high temperature of 950˚C also enhance the hardness, corrosion and wear-corrosion behavior of Inconel 718 alloy, and were increased with increasing holding time.