Coated Titanium Anode Wire

Key specs at a glance

• Substrate: Grade 2 titanium wire per ASTM B863
• Coating: RuO₂-IrO₂ (chlorine) or IrO₂-Ta₂O₅ (oxygen), 5 to 20 microns
• Diameter: 1.0 to 3.0 mm standard, 0.5 to 6.0 mm on request
• Supply form: coils (50 to 100 m per spool) or straight lengths
• Continuous current density: 100 to 1,000 A/m² depending on duty
• Service life: 2 to 5 years at rated electrolysis conditions; 10+ years in low current cathodic protection

What Is an MMO Titanium Wire Anode?

An MMO titanium wire anode is a dimensionally stable anode (DSA) in wire form. A drawn titanium wire is the conductive core, and a thin mixed metal oxide (MMO) catalytic layer covers the full outer surface. The wire is drawn from Grade 2 commercially pure titanium, which combines good formability with the corrosion resistance the anode needs in soil, seawater, and electrolytes.

Wire anodes fill a specific niche: they are flexible enough to be bent into anode loops, woven into mesh screens, or strung down a deep well. Because the coating covers the entire circumference, a wire anode presents its full surface to the electrolyte from every direction, which matters in soil backfill and in cells with complex geometry. The trade-off is a smaller cross section than a rod, so the working current per length is lower.

Coating Systems and Selection

Coating selection follows one rule: match the coating to the reaction the anode must drive.

• RuO₂-IrO₂ (ruthenium iridium oxide): the standard coating for chlorine evolution in chloride-rich environments. This is the most common choice for wire anodes because deep well cathodic protection, seawater electrochlorination, and many plating baths are chloride based. The coating generates active chlorine at low overpotential and stays dimensionally stable.
• IrO₂-Ta₂O₅ (iridium tantalum oxide), typical molar ratio about 70:30: the standard coating for oxygen evolution in acidic sulfate media. Use it where the wire anode runs in sulfuric or mixed acid duty, such as certain electrowinning and organic oxidation applications. Ruthenium based coatings are not suitable for sustained oxygen evolution in strong acid.

The wire is degreased and etched before coating. The MMO layer is applied in multiple thermal decomposition cycles to a thickness of 5 to 20 microns with a precious metal loading of 5 to 50 g/m², set against your current density and target life. Coated wire can be supplied bare or pre-formed, such as straight lengths, coils, or woven panels.

Technical Specifications

Applications

1. Deep well and remote cathodic protection: wire anodes are strung down deep well anode beds and laid in remote groundbeds for pipelines and storage tanks. The flexibility lets the string follow the well without kinking, and the full circumference coating feeds current evenly into the backfill.
2. Woven mesh anodes: coated wire is woven into mesh panels for cathodic protection of concrete structures and for electrolysis cells where a woven structure suits the flow field. Woven mesh flexes where expanded mesh cannot.
3. Electroplating and small cells: wire anodes serve as auxiliary anodes in plating racks, basket anodes for precious metal plating, and electrodes in small laboratory or pilot cells where dimensional flexibility matters.
4. Electrochemical synthesis: wire electrodes in tubular or packed bed reactors for oxidant generation and organic electrosynthesis, where the wire doubles as both electrode and structural element.

How to Specify a Wire Anode

Send us these five items and we will confirm the design within 48 hours:

1. Application and environment. Deep well CP, woven mesh, plating, or synthesis, plus the electrolyte or backfill chemistry. This decides the coating system.
2. Current and length. The design current per meter of wire and the total length you need, which together set the diameter and loading.
3. Diameter and form. Wire diameter, and whether you need coils, straight lengths, or pre-formed panels and loops.
4. Connection method. How the wire will be terminated and connected to the conductor, such as crimp, weld, or splice.
5. Target service life. We set the precious metal loading against this number, since loading is the main cost driver.

Frequently Asked Questions

What is an MMO titanium wire anode used for?

Wire anodes are used where the anode must bend, weave, or reach into a confined space. The main applications are deep well and remote cathodic protection groundbeds, woven mesh anodes for concrete protection, auxiliary and basket anodes in plating, and electrodes in small or tubular electrolysis cells.

How long does an MMO titanium wire anode last?

In electrolysis duty at rated conditions, expect 2 to 5 years. In cathodic protection at low current density, the anode typically lasts a decade or more, because coating consumption is measured in milligrams per year. Actual life is set by current density, environment, temperature, and coating loading.

What wire diameters are available?

Standard diameters are 1.0, 1.5, 2.0, and 3.0 mm, and we produce 0.5 to 6.0 mm on request. The diameter is chosen against the working current per meter and the mechanical requirements of the installation, such as bending radius in a deep well or weave pattern in a mesh panel.

Can coated titanium wire be formed after coating?

Forming after coating risks cracking the MMO layer, so we recommend forming first. The wire is bent, woven, or strung into its final shape, and the coating is then applied over the finished geometry. If you need to adjust a shape in the field, keep the bend radius generous and avoid sharp kinks at the coated surface.