The high-throughput Preparation and Characterization on the Corrosion Behaviors of Gradient Al-Cr Complex Coatings on the Novel Co-Al-W Based Superalloy

Jiangbo Sha*, Yan Li, Xiuyun Zhao

Beihang University, Beijing, 100191, China

ABSTRACT: The high-throughput preparation and high-throughput characterization on the anti-oxidation and -corrosion performance of gradient coatings is one of the most important issues of the genetic engineering. In order to improve the oxidation and corrosion resistance of the new Co-Al-W based superalloy, the Al-Cr coating with composition gradients was high-throughputly prepared by using multi-arc ion plating technology. Then, the gradient Al-Cr coating was rapidly and high-throughputly corroded at high temperature and the corrosion behaviors were discussed. In the gradient Al-Cr coating, Al content gradually decreased from 75at.% to 15at.% from the upper to the bottom of the substrate (Fig. 1a), while the Cr element increased from 25at.% to 85at.% (Fig. 1b). With decrease of Al content or increase of the Cr content the phase constitution of the gradient Al-Cr coating changed from Al80Cr20 and Al17Cr9 to Al8Cr5 and α-Cr. High-throughputly corroded at 1000°C for 30 min reveals that the corroded layer consisted of out-layer (Al₂O₃+Cr₂O₃), inter-diffusing layer (Fig. 2a) and un-corroded Al-Cr coatings (Fig. 2d), while the inter-diffusing layer was identified to be mixture of CoAl (Fig. 2b) and Co3W (Fig. 2c). Thus, a high-throughput preparation and characterization on the gradient Al-Cr coatings has been conducted.

Figure 1. Composition maps of Al-Cr coatings                                                           Figure 2. Structure of corroded coatings

Keywords: Genetic engineering, Gradient Al-Cr coatings; high-throughput preparation and characterization