The QPQ、Gas Nitriding And Ion Nitriding Research Of Corrosion Resistance

Nitriding process is essentially ferrite of low temperature chemical heat treatment, due tothe high wear resistance, hardness and good fatigue resistance and so on characteristics,therefore in industry widely. QPQ salt bath composite processing realizes the effectivecompound nitriding process and oxidation process, as a short development history of metalsurface strengthening technology, it is harmless to the environment not only, and metalprocessing has high corrosion resistance, hardness and deformation is small, etc. Goodpermeability of ion nitriding layer of compact structure, and have high corrosion resistance,abrasion resistance, fatigue resistance, and the advantages of short production cycle, but the ionnitriding process cost is high and the operation is relatively difficult. Gas nitriding developmenthas a long history and its production process is advantageous for the operation, control and lowcost and conventional gas nitriding for a long time. This paper mainly studies QPQ, ionnitriding, gas nitriding influence on material corrosion resistance. Objective is to compare andsummarize three kinds of technology to raise the material the difference of corrosion resistance.This experiment usd35CrMo and45steel as experiment material,on the QPQ compoundtreatment and gas nitriding,ion nitriding,through SEM, EDS and metallographic microscopeand salt fog test,studied the permeability layer’s microstructure, element distribution andcorrosion resistance, and comparison. Experiments show that: under the sameconditions,sample after QPQ complex treatment for resistance to salt spray experiment of ionnitriding of21times above, for more than five times as much as gas nitriding, ion nitriding ofthe corrosion resistance of the worst. QPQ compound processing technology and thepermeability of the samples gas nitriding layer distribution of nitrogen element in almost thesame. From seeping layer’s microstructure, the QPQ compound treatment, ion nitriding andpercolation of gas nitriding layer structure is roughly same, but the QPQ outside there is a layerof oxide film,This is was an important reason for its corrosion resistance is good.