Corrosive Wear
How does corrosive wear differ from pure corrosion?
Pure corrosion forms a static protective film; corrosive wear mechanically removes this film via sliding or abrasion, enabling continuous re-corrosion and rapid material loss.
What is the role of lubricants in mitigating corrosive wear?
Lubricants must contain corrosion inhibitors and have stable pH to neutralize acidic byproducts; degraded lubricants with high acid numbers actively accelerate the chemical reaction.
Can corrosive wear occur in dry conditions?
Yes; it is classified as dry corrosive wear when the corrosive medium is atmospheric like oxygen, H₂S, or SO₂ without moisture, though moisture typically accelerates the electrochemical reaction.
What is the mathematical relationship for wear rate in tribocorrosion?
The total wear rate W_total is often modeled as W_total = W_mechanical + W_corrosion + ΔW_synergy, where the synergy term ΔW_synergy accounts for the amplified loss from film removal.
Corrosive wear, also known as tribocorrosion or chemical wear, is material degradation from the synergistic attack of simultaneous chemical corrosion and mechanical wear. Sliding or abrasion removes protective corrosion films like oxides, exposing fresh material to further electrochemical attack, accelerating material loss beyond the sum of individual processes.
In manufacturing and maintenance, corrosive wear is managed in CMMS by tracking environmental exposure to acids, moisture, and salts paired with mechanical motion like sliding or rolling. Preventive actions include applying corrosion-resistant coatings, selecting inert materials, controlling lubricant chemistry to neutralize acids, and reducing operating temperatures to slow reaction rates. This approach minimizes unplanned downtime and extends equipment life in harsh environments.
Pitting in Plastic Processing: Acids from plastic degradation attack screw and barrel surfaces, causing deep pitting in metering/transition zones, leading to product contamination and loss of extrusion efficiency.
Fretting Corrosion: Low-amplitude oscillatory contact from vibration removes protective films repeatedly, accelerating wear in bolted joints, bearings, or gear meshes where vibration is unmitigated.
Three-Body Abrasion from Oxide Particles: Hard oxide particles from corrosion trapped between sliding surfaces act as abrasives, increasing wear rates by up to 3× when filtration or lubricant cleanliness is neglected.