The effect of oxide film properties on the corrosion behavior of SiC/Al metal-matrix composites

Miscellaneous · Tue Jan 01 00:00:00 EST 1991

OSTI ID:5499819

Golledge, S L

Oxide growth on pure aluminum, aluminum alloy 6061, and the aluminum-based metal matrix composite SiC/AA6061 was studied, and the properties of the oxides related to the pit-initiation behavior of the materials. The objectives of the work were to identify the effect of alloying elements and SiC reinforcement on the oxide film, and to better understand how the oxide properties control pit initiation behavior. To this end, electrochemical and optical studies of the materials were carried out in a buffered sodium/boric acid solution at pH values of 8.4 and 7.2. The alloy and metal-matrix composite showed a slightly lesser tendency to pit than pure aluminum, as measured by the pitting potential. The oxide on the composite was less resistant to pit initiation, and was found to exhibit slower repassivation rates than the other materials. The repassivation behavior and resistance to pit initiation were quite similar in the case of the alloy and the pure aluminum. Induction times for pit initiation were consistent with the predictions of Heusler's model for the breakdown of passivity.

• Research Organization: Johns Hopkins Univ., Baltimore, MD (United States)
• OSTI ID: 5499819
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM
PITTING CORROSION
ALUMINIUM ALLOYS
COMPOSITE MATERIALS
SILICON CARBIDES
BORIC ACID
CORROSIVE EFFECTS
MATRIX MATERIALS
OXIDATION
SODIUM
ALKALI METALS
ALLOYS
BORON COMPOUNDS
CARBIDES
CARBON COMPOUNDS
CHEMICAL REACTIONS
CORROSION
ELEMENTS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
MATERIALS
METALS
OXYGEN COMPOUNDS
SILICON COMPOUNDS
360604* - Materials- Corrosion
Erosion
& Degradation
360105 - Metals & Alloys- Corrosion & Erosion