Anodization Mechanism on SiC Nanoparticle Reinforced Al Matrix Composites Produced by Power Metallurgy

Materials

Sonia C. Ferreira¹  Ana Conde²  Mar໚ A. Arenas²  Luis A. Rocha³  Alexandre Velhinho¹ 

[1] Materials Research Centre/Institute for Nanostructures, Nanomodelling and Nanofabrication (CENIMAT/I3N), Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal; E-Mails:;Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC), Avda. Gregorio del Amo, 8, 28040 Madrid, Spain; E-Mail:;Centre for Mechanics and Materials Technologies (CT2M), Research Group on Functionalized Materials and Surfaces Performance, Campus de Azurém, 4810-058 Guimarães, Portugal

关键词: aluminum matrix composite;    powder metallurgy;    anodizing;    oxide film;    nanosized reinforcements;   

DOI  :  10.3390/ma7128151

来源: mdpi

【 摘 要 】

Specimens of aluminum-based composites reinforced by silicon carbide nanoparticles (Al/SiC_np) produced by powder metallurgy (PM) were anodized under voltage control in tartaric-sulfuric acid (TSA). In this work, the influence of the amount of SiC_np on the film growth during anodizing was investigated. The current density versus time response and the morphology of the porous alumina film formed at the composite surface are compared to those concerning a commercial aluminum alloy (AA1050) anodized under the same conditions. The processing method of the aluminum alloys influences the efficiency of the anodizing process, leading to a lower thicknesses for the unreinforced Al-PM alloy regarding the AA1050. The current density versus time response is strongly dependent on the amount of SiC_np. The current peaks and the steady-state current density recorded at each voltage step increases with the SiC_np volume fraction due to the oxidation of the SiC_np. The formation mechanism of the anodic film on Al/SiC_np composites is different from that occurring in AA1050, partly due the heterogeneous distribution of the reinforcement particles in the metallic matrix, but also to the entrapment of SiC_np in the anodic film.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.