Characteristics of AISI 420 Stainless Steel Modified by Low-Temperature Plasma Carburizing with Gaseous Acetone

In this research work, low-temperature carburizing of AISI 420 martensitic stainless steel was conducted at 460 °C for different amounts of time using an acetone source. The microstructure and phase structure of the carburized layers were characterized by optical microscope and X-ray diffraction. The properties of the carburized layers were tested with a microhardness tester and an electrochemical workstation. The results indicate uniform layers are formed on martensitic stainless steel surfaces, and the carburized layers are mainly composed of carbon “expanded” α (αC) and Fe3C phases. The property tests indicated that after plasma–carburizing, the hardness of the stainless steel surface can reach up to 850 HV0.1. However, the corrosion resistance of stainless steel decreased slightly, and the corrosion characteristic of stainless steel was altered from pitting to general corrosion. The semiconductor characteristic of the passivation film on stainless steel was transformed from the p-type for untreated specimens to the n-type for carburized specimens.