Characteristics of aluminum phosphate sealed chromium oxide coatings
- Tampere Univ. of Technology (Finland)
Plasma sprayed chromium oxide (Cr{sub 2}O{sub 3}) coatings are used to protect metals against wear and corrosion. However, these coatings still have too high open porosity for good corrosion resistance and protection of the base material. Porosity of the Cr{sub 2}O{sub 3} coatings can be reduced significantly by using phosphate based sealants. In this study atmospheric plasma sprayed (APS) chromium oxide coatings were sealed with aluminum phosphate at different temperatures. Wear resistance was evaluated by rubber wheel abrasion tests and particle erosion tests. Corrosion resistance of the coatings was measured by anodic potentiodynamic polarization technique and constant potential tests. Aluminum phosphate sealed coatings showed significantly better corrosion resistance than the unsealed ones. The authors found that phosphate seems to act as a binder and thus improved mechanical properties were measured for sealed chromium oxide; higher hardness and higher wear resistance as compared with the corresponding unsealed coatings. The resistance against abrasion and erosion wear was found to be almost equal to those of Si{sub 3}N{sub 4}, SiC, Al{sub 2}O{sub 3} and ZTA bulk ceramics.
- OSTI ID:
- 379571
- Report Number(s):
- CONF-9509182--; ISBN 0-87170-541-9
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALUMINIUM HYDROXIDES
ALUMINIUM PHOSPHATES
CHROMIUM OXIDES
COMPOSITE MATERIALS
CORROSION RESISTANCE
CURRENT DENSITY
ELECTRIC POTENTIAL
ELECTROCHEMICAL CORROSION
EROSION
EXPERIMENTAL DATA
FABRICATION
IMPREGNATION
MICROHARDNESS
PHOSPHORIC ACID
PLASMA ARC SPRAYING
POWDERS
SAND
SODIUM CHLORIDES
WEAR RESISTANCE