EPMA and quantitative MCs+-SIMS of metal-DLC coating materials

Compositional characterization of metal-DLC (metal-containing diamond-like carbon) hard coatings is carried out by (WDS)-EPMA and MCs+-SIMSL. EPMA enables accurate (+- 5% relative) quantitative analysis including minor concentrations (0.1 -10 at%) of N, O and Ar. Under conditions of "near-surface" EMPA Eo < 10 keV) the influence of surface oxide films on "pure" metal standards may be a limiting factor in respect of accuracy. Depth profiling of sufficiently "thick" layered structures (film thickness > 2 µm) is carried out by EPMA-line scans along mechanically prepared bevels. The depth resolution is about 0.2 µm. SIMS in the MCs+-mode enables high resolution (< 20 nm) depth profiling of metal-DLC layered structures including the determination of H (1-20 at%). MCs+-SIMS, i.e. employing Cs+ primary ions and monitoring MCs+ molecular secondary ions (M is the element of interest) is presented as a promising route towards sufficiently accurate (10-20 %) SIMS-quantification. Matrix-independent relative sensitivity factors for MCs+-SIMS are derived from homogeneous coating materials defined by EPMA. EPMA proves to be also useful to detect problems related to SIMS of Ar in metal-DLC materials. The combination EPMA-SIMS is demonstrated as an effective analytical strategy for quality control in industrial production and to support the development of metal DLC layered structures with optimum tribological properties.