Deposition of Boron Containing Coatings Using MO-PACVD Process to Protect Aluminium Casting Tools

Abstract
In this paper the synthesis of (B,C,N), Zr(B,C) and Zr(B,C,N) layers is investigated by means of DC pulsed plasma assisted CVD using organic compounds as precursors. The process parameters such as coating temperature, gas pressure, gas mixture, plasma parameters are varied to deposit functional coatings on hot-work steel used in the aluminium die casting industry. One of the objectives is to realize a layer type which withstands the severe service conditions in aluminium die casting. Another objective is to lower the coating temperature. The layers have been studied by light- and scanning electron microscopy (SEM). The properties of the deposited layers are determined by various analytical methods such as WDS-analysis for the chemical composition and X-ray diffraction (XRD) for the morphology. The hardness and adhesion of the layers were measured to determine the mechanical properties. The adhesion to liquid aluminium is investigated and compared to TiN layers deposited with TiC1₄ as precursor.