FIB Milling and Characterization of CrC Coatings on Tool Steel Substrate

R.M. Minev(a), M. Ilieva(b), J. Kettle(a), G. Lalev(a), S.S. Dimov(a), I. Dermendjiev(b), R. Shishkov(b)
a: Manufacturing Engineering Center, Cardiff University, Cardiff, CF24 3AA, UK
b: Department of Materials Science and Technology, Rousse University, Bulgaria

Abstract

In microtools, the base of a die should be ductile, and its working surface should be hard, having low roughness, low wettability and high erosion resistance. To ensure this diverse range of properties, nano-crystalline CrC coatings were deposited onto 12% Cr tool steel with DC magnetron sputtering in a vacuum furnace with electrical graphite heating. Subsequently, these properties were studied by application of different metallographic techniques. Corrosion resistance as studied by means of potentiodynamic anodic polarization. A STEM analysis of the structure was performed on samples repared with Focused Ion Beam (FIB) using nano-manipulator. The mechanical properties and grain size were determined and statistically analyzed. Studies using X-ray diffraction and scanning electron microscopy were also performed. Rectangular trenches were produced in the coating using FIB XB1540 Carl Zeiss SEM/FIB system to study the effects of the target ion beam current, exposure time and ion fluence on the sputtering yield and roughness of the samples profile. Some essential parameter’ windows for productive milling with speed >1 μm/min and for best surface integrity were determined during the experiments.