A dependable Ru-Ir MMO anode order is not a request for a color, a Ru:Ir ratio or an outside dimension. It is a controlled technical basis connecting chlorine-evolution duty, chemistry, active coated area, electrical loading, coating metric, substrate, connection, qualification and operating responsibility.
1. Confirm Chlorine Evolution and the Supply Boundary
Name the intended anodic reaction, desired chlorine/hypochlorite or other process result, production/output basis and any competing reactions. Define whether HELE supplies an electrode, frame/assembly, replacement part or other agreed components; identify who owns cell, rectifier, controls, piping, process performance, installation and commissioning.
- State new design, OEM replacement, retrofit or recoating evaluation.
- List included tabs, cables, bus connections, frames, seals, supports, spares and documents.
- Record drawings, specifications, revisions, standards and precedence.
- Separate electrode acceptance from full-system output and product-quality responsibility.
2. Define the Complete Chloride Chemistry
Provide feed and operating composition ranges, not a single chloride value. Include relevant salts, impurities, hardness, sulfate, fluoride, bromide or other halides when present, pH, conductivity, temperature, flow/agitation, gas release, solids, scale and cleaning chemistry.
- State normal, minimum, maximum, startup, shutdown, standby and upset conditions.
- Describe feedwater/brine variability and any pretreatment.
- Identify product concentration/quality target and competing side reactions.
- Assign responsibility for chemistry monitoring and operating-limit control.
3. Separate CER from OER and Other Coating Families
Ru-Ir is a common starting direction for chlorine evolution, whereas Ir-based / Ir-Ta coatings are commonly screened for oxygen-evolution duty. Both can contain iridium; the element name does not determine the correct reaction pathway.
| Question | Ru-Ir CER review | Ir-based / Ir-Ta OER review |
|---|---|---|
| Intended anodic reaction | Chlorine evolution | Oxygen evolution |
| Primary chemistry review | Complete chloride medium and competing reactions | Complete OER-oriented electrolyte and contaminants |
| Shared engineering inputs | Temperature, current-density basis, total current, duty, active area, geometry, connection, flow and qualification | |
Review the IrO₂ / Ir-Ta coated titanium anode page when oxygen evolution is the intended duty.
4. Specify Coating Composition, Loading and Acceptance Separately
A Ru:Ir ratio does not define precursor chemistry, application route, total oxide loading, precious-metal loading, thickness, thermal history, morphology, active area, electrochemical performance or life. Specify only metrics that can be measured and accepted through an agreed method.
- Identify the controlled coating specification or performance requirement.
- For composition, loading or thickness, state metric, units, area basis, method, calibration, sampling and limits.
- Map coated, masked, contact and transition zones.
- Define qualification samples and change-control requirements.
5. Define Titanium Substrate by Product Form
State grade/UNS, applicable product-form specification and revision, condition, dimensions, tolerances and lot traceability. ASTM B265 may apply to strip, sheet and plate within its scope; tube, bar/rod and wire require their own material basis. No substrate standard qualifies the coating or completed electrode.
- Control remaining thickness after forming, machining and surface preparation where critical.
- Define mesh geometry/opening and the area calculation used.
- Define welds, frames, tabs, threads, holes, edges and heat-affected-zone acceptance.
- Link substrate heat/lot, fabrication and coating batch to the shipped item.
6. Freeze Geometry, Active Zones and Cell Fit
For mesh, plate, tubular, rod or assembly designs, define overall dimensions and tolerances, coated faces, inactive contact/mounting regions, electrode spacing, orientation, supports and fluid/gas access. Overall envelope area and effective coated area are not interchangeable.
Opening, strand, thickness, projected/geometric area convention, coated sides, frame and feed.
Length, width, thickness, flatness/form, active faces, edges, masking, tab and mounting.
OD/diameter, wall where applicable, length, active zone, ends, threads/lead and support.
Frame, welds, active panels, current feeds, seals, replaceable interfaces and lifting/handling.
7. Define Current Density with Its Denominator
State total current, voltage range, current control, current density, duty cycle, peak duration, ramping, polarity and fault conditions. Every current-density value must identify the area denominator and active-zone drawing.
- Differentiate one-side, two-side, exposed geometric, mesh projected and other agreed area bases.
- State electrode gap, counter-electrode, flow and current-distribution assumptions.
- Define normal and peak loading plus start/stop and standby conditions.
- Identify acceptable voltage/reference basis for any electrochemical test or operating limit.
Calculation control
Do not compare current density, coating loading or price per anode until the coated-area convention and excluded contact/mounting zones are aligned.
8. Control the Electrical Connection and Seal Boundary
Define tab, conductor, cable, threaded interface or bus connection; contact area; weld/mechanical joint; seal; strain relief; transition location; polarity marking and inspection. A coating can be acceptable while the assembly fails through resistance, heating, ingress or poor load transfer.
- Keep dissimilar-metal connections isolated from electrolyte where required.
- State connection resistance, voltage-drop, insulation or leak acceptance when applicable.
- Show liquid level, coated/uncoated transition and service-access boundary.
- Define factory-tested and field-completed interfaces.
9. Freeze the Manufacturing and Change-Control Route
The route may include cutting/forming, welding or machining, cleaning and activation, precursor application, staged thermal treatment, assembly, sealing and final inspection. Confirm what applies to the ordered geometry and which records are required.
- Identify critical substrate, coating-batch, active-zone and thermal-process controls.
- Protect prepared/coated surfaces from contamination and mechanical damage.
- Define first-article or qualification requirements for a new design.
- Require approval for material, formulation, route, tooling or source changes that affect the validated basis.
10. Define Verification Evidence and Its Limits
| Control | Possible evidence when ordered | Boundary |
|---|---|---|
| Substrate | MTC, heat/lot, dimensions and surface condition | Does not prove coating performance |
| Coating batch | Specification/recipe reference, application/thermal record, active-zone review | Scope follows PO/ITP |
| XRF | Surface elemental-composition readings under a calibrated plan | Not automatic proof of loading, thickness, adhesion or life |
| Loading / thickness | Agreed gravimetric, analytical, cross-sectional or validated method | Metric, units, area, sampling and uncertainty must be stated |
| Electrical / electrochemical | Continuity/resistance, potential/polarization or project test | Cell, reference and conditions must be defined |
| ALT | Conditioned sample test with full method and end point | Not a direct field-life guarantee |
11. Build Design-Life, ALT and Warranty Bases Separately
Life depends on coating system, loading metric, active area, chemistry, temperature, current duty, flow, polarity, connection, cleaning, shutdowns and the end-of-life criterion. A year value without those inputs is not comparable.
- Separate design target, calculated basis, qualification test, ALT, field expectation and commercial warranty.
- For ALT, record sample geometry, electrolyte, concentration, temperature, current-density basis, waveform/duty and end point.
- State any field-correlation method and its limitations.
- Define operating records and events that affect the life/warranty basis.
12. Investigate Performance Loss Before Assigning Cause
Preserve chemistry, current/voltage trend, temperature, flow, polarity events, cleaning history, operating hours, visual condition, connection measurements and cell geometry before cleaning or dismantling.
- Chemistry drift or competing reactions may change coating duty.
- Reduced active area, scale, gas blanketing, gap or flow changes may increase local loading.
- Connection resistance, seal ingress, short circuit or reverse polarity may affect performance.
- Mechanical damage, exposed substrate, coating wear or passivation require separate evidence.
13. Define Installation, Commissioning and Maintenance
Specify handling protection, installation orientation and gap, electrical/polarity verification, ramp-up, baseline readings, operating window, monitoring, cleaning and shutdown procedure. Cleaning method must be approved for the coating, substrate, deposits and process.
The electrode supplier cannot alone guarantee full-cell output when feed chemistry, hydraulics, cathode condition, gap, power control and cleaning remain outside the supply scope. Assign each system responsibility explicitly.
14. Assess Recoating as a Conditional Requalification
Inspect remaining thickness, deformation, pitting, cracks, welds, threads, contact areas, connection, seals, contamination and dimensional compliance. Review whether the process duty has changed. Define old-coating removal, preparation, new coating, qualification, identification and acceptance.
Recoating does not by itself prove restoration of original efficiency, life or warranty. The reused substrate and new coating require an agreed acceptance basis.
15. Normalize Technical and Commercial Quotations
Cost and schedule can be driven by coating basis, precious-metal market, active area, substrate form, fabrication, masking, connection, qualification, destructive testing, sampling, documents, quantity, packing and logistics.
- Compare one frozen technical revision and active-area convention.
- Separate development/qualification, production items, spares, assemblies, tests, documents and freight.
- Record MOQ driver, validity, schedule assumptions, Incoterm, destination and exclusions.
- Compare lifecycle claims only when chemistry, duty, end point and maintenance assumptions match.
16. Complete Ru-Ir MMO Anode Purchase Guard
16.1 Reaction and process result
- Confirm chlorine evolution and identify competing reactions.
- Define required chlorine/hypochlorite or other process-output basis.
- Separate electrode scope from complete-cell and process-performance responsibility.
16.2 Chemistry and operating window
- List chloride and complete composition ranges, impurities, pH and conductivity.
- State temperature, flow/agitation, solids, scale, gas and cleaning chemistry.
- Include startup, shutdown, standby, peak and upset conditions.
16.3 Coating and active-zone definition
- State coating performance/composition basis and controlled metric.
- Define loading, thickness and surface composition separately when required.
- Show coated, masked, contact and transition zones on the drawing.
16.4 Substrate and geometry
- State grade/UNS, product-form standard, condition and heat/lot traceability.
- Freeze dimensions, tolerances, mesh-area convention, welds, tabs and mounting.
- Define overall, exposed and effective coated area without mixing them.
16.5 Electrical and connection basis
- State current, voltage, density denominator, duty, peaks, ramp and polarity.
- Define electrode gap, current-distribution assumptions and counter-electrode.
- Control contact, weld/joint, cable/feed, seal, strain relief and acceptance.
16.6 Life, inspection and evidence
- Define design conditions, life method, end point and exclusions.
- For every result state method, calibration, sample, locations, units and limits.
- Separate XRF, loading, thickness, adhesion, electrochemical test and ALT claims.
16.7 Installation, maintenance and failure
- Define handling, installation, polarity check, ramp, baseline and monitoring.
- Approve operating limits and cleaning methods.
- Preserve process/electrical evidence before cleaning or dismantling after failure.
16.8 Recoating and commercial scope
- Inspect substrate and connections before approving recoating.
- Define stripping, preparation, requalification, warranty and identification.
- Normalize quantity, spares, tests, documents, packing, Incoterm, schedule and exclusions.
Red flags before purchase order
Target reaction and competing reactions are not established.
One-side, two-side, mesh projected or exposed coated area is not defined.
Composition, loading, thickness, adhesion and life are conflated.
Substrate condition and requalification are unknown.
Decision gate
Do not release the order until CER duty, chemistry, coating, substrate, active area, electrical loading, connection, life method, evidence, operation and commercial scope describe one verifiable deliverable.
17. RFQ and Pre-Order Checklist
Target reaction/output, full chloride chemistry, impurities, pH, temperature, flow and cleaning.
Total current, voltage, density denominator, duty, peaks, polarity, gap and distribution.
Coating metric, active zone, design-life method, ALT boundary, end point and warranty basis.
Grade/form standard, dimensions, tolerances, welds, tab/cable/feed, seal and mounting.
MTC, coating/inspection reports, test methods, commissioning, monitoring, cleaning and failure records.
Quantity/spares, included scope, MOQ, packing, destination, Incoterm, required date and exceptions.
18. Ru-Ir MMO Anode Purchasing FAQ
What is the first decision in a Ru-Ir anode RFQ?
Confirm that chlorine evolution is the intended anodic reaction and define the process result. The coating name, chloride presence or application label alone is not enough.
Should an RFQ specify a Ru:Ir ratio?
Only when supported by a controlled specification and appropriate acceptance method. A ratio alone does not define precursor route, total loading, oxide structure, active area, thermal history, performance or life.
What does XRF verify?
Under a documented calibration and measurement plan, XRF may support surface elemental-composition assessment. It does not automatically prove total precious-metal loading, coating thickness, through-depth distribution, adhesion or service life.
How should an accelerated life test be reported?
State sample geometry, coating basis, electrolyte, concentration, temperature, current-density denominator, waveform or duty, end point and interpretation limits. The result is not a direct field-life guarantee.
What is the main boundary of ASTM B265?
ASTM B265 covers titanium and titanium-alloy strip, sheet and plate within its scope. It does not qualify the Ru-Ir coating, connection, electrochemical performance or completed anode.
How should two Ru-Ir quotations be compared?
Normalize reaction, chemistry, electrical duty, active-area basis, coating metric, substrate, geometry, connection, life method, tests, documents, quantity, packing, Incoterm and exceptions.