Samples were cut from AISI H13 steel rods and machined into discs with 18 mm diameter and 5 mm thickness.
The samples were ground, austenitized at 1020 °C for 30 min, quenched in oil, tempered for 2 h at 600 °C, metallographically polished, degreased with ether, and then ultrasonically cleaned in acetone for 30 min.
After the nitriding process, the samples were prepared for characterization in two ways : (1) analyze each one of the newly exposed surfaces with GIXRD and CEMS for phase identification, (2) polished cross sections for hardness profiles measured in a dynamic ultra-microhardness tester, and for nitrogen concentration analysis with an electron microprobe analyzer.
After Nital etching, images of the cross section were obtained in a scanning electron microscope.