Effect of nitriding nitrogen pressure on the structural, morphological, mechanical and tribological properties of plasma nitrided hard chromium electroplated layer

ABSTRACT This paper investigates the structural, morphological, mechanical and tribological properties of a hard chromium electroplated layer plasma nitrided in a pure nitrogen atmosphere at three different nitrogen pressures: 3.5, 4 and 5 Torr for 90 minutes at 600°C. The results showed that after plasma nitriding at 4 and 5 Torr, a well-defined Cr2N layer with a rough and porous morphology was created and the micro-cracks in the hard chromium electroplated layer were almost filled with chromium nitrides. They also showed that increasing the nitrogen pressure from 3.5 to 4 Torr resulted in a significant increase in wear resistance.