Plasma Nitriding Austenitic Stainless Steel

However the interfacial ohmic loss across the metallic bipolar plate and membrane electrode assembly due to corrosion increases the overall power output of pemfc.

Plasma nitriding austenitic stainless steel. The microstructure layer thickness hardness and chemical microcomposition were evaluated employing optical microscopy vickers hardness and scanning electron microscopy techniques wds microanalysis. This enhances the wear resistance of the steels with maintaining corrosion resistance by producing expanded austenite known as the s phase which dissolves excessive nitrogen. The nitrided layers produced by low temperature 400 500 c plasma nitriding on austenitic stainless steels aisi 316 304 and 321 have been characterised by x ray diffraction in conjunction. The active screen plasma nitriding can significantly reduce the interfacial contact resistance icr value of 316 austenitic stainless steel mainly due to the formation nitrogen supersaturated s phase layer.

Considering low temperature plasma assisted nitriding and carburizing of stainless steels it can be affirmed that the treatment of austenitic stainless steels was extensively studied. Austenitic stainless steel 316l is a traditional candidate for metal bipolar plates. Austenitic stainless steels contain nickel which has the potential to play an important role in. Plasma nitriding has been widely used as an effective way to enhance the hardness and wear resistance of austenitic stainless steel however the plasma nitriding efficiency of austenitic stainless steel is much lower than ferrite stainless steel because the diffusion coefficient of nitrogen in closely stacked austenite phase is several magnitudes smaller than in.

An austenitic stainless steel type aisi304 specimen is employed for plasma nitriding at 673 k for 14 4 ks by 60 pa. In this study low temperature plasma nitriding is applied to austenitic stainless steels at temperatures below 450 c. The icr value of the nitrided samples decreased with increasing the treatment temperature. These processes are most commonly used on high carbon low alloy steels.

Each fundamental process in this low temperature inner nitriding is analyzed by xrd scanning electron microscopy sem electron dispersive x ray spectroscopy edx and electron back scattering diffraction ebsd. They are also used on medium and high carbon steels titanium aluminium and molybdenum in 2015 nitriding was used to generate unique duplex microstructure martensite austenite austenite ferrite. This enhances the wear resistance of the steels with maintaining corrosion resistance by producing expanded austenite known as the s phase which dissolves excessive nitrogen. The nitriding behavior of austenitic stainless steels aisi 304 and 316 was studied by different cold work degree 0 after heat treated 10 20 30 and 40 before nitride processing.

Nitriding is a heat treating process that diffuses nitrogen into the surface of a metal to create a case hardened surface. On the other hand studies for martensitic stainless steels have been less considered and several opened questions.