The service life and electrocatalytic activity of tantalum oxide/iridium oxide
coated titanium plate and mesh anodes used in the electrolytic production
of chromic acid were investigated by performing accelerated life tests,
voltammetric and chronoamperometric measurements in chrome (VI)
solutions.
Experimental results showed that the service life for the coated mesh
anode was 1059 hours, compared to 828 hours for the plate anode at a
current density of 1.2 A cm-2. In addition, the coating failed earlier in higher
chromic acid concentration. Physical analysis by SEM and EDS before
and after accelerated life test confirmed that the deactivation was a result
of corrosion of IrO2 followed by titanium substrate passivation.
A simple and rapid method for assessing the electrocatalytic activity of
iridium–tantalum oxide coating based on a chronoamperometric technique
was developed.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/5794 |
| Date | 23 October 2008 |
| Creators | Ntunka, Mbuyu Germain |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
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