Hardness, mechanical and morphological properties of iron nitride thin films

A study of mechanical properties, hardness and morphology of iron samples ( 99.9%), as a function of nitrogen content, is presented. An increase up to similar to 300% in hardness was obtained. Nitriding of iron substrates were performed in an ECR microwave plasma source with a high-density regimen of ionized particles (5 x 10(11) cm(-3)) under a pressure of 4.0 x 10(-4) Tor r. Working atmosphere was a H-2/N-2 gas mixture, 100%/0%, 90%/10%, 85%/15%, 80%120% and 0%/100%. The pressure of working gas; the microwave power, 300 W; the processing rime, 20 min and the substrate temperature were all kept constant during the nitriding processes. Sample characterization was carri ed out by X-ray diffraction, scanning electron microscopy and microhardness ; mechanical properties were determined with an Instron equipment.