Washcoat: Thickness 20-150 μm, Porosity 40-70%

Component Specifications

Definition

A washcoat is a thin, porous ceramic layer applied to the surface of catalyst substrates (typically honeycomb monoliths) in Selective Catalytic Reduction (SCR) systems. It serves as a high-surface-area support structure for active catalytic materials (such as vanadium, tungsten, or zeolite-based compounds) that facilitate the reduction of nitrogen oxides (NOx) with ammonia or urea. The washcoat enhances catalytic activity, thermal stability, and poison resistance while maintaining low pressure drop across the system.

Working Principle

The washcoat provides a large surface area for dispersing active catalytic sites, enabling the SCR reaction where NOx gases react with ammonia/urea to form nitrogen and water. Its porous structure maximizes gas-catalyst contact while minimizing diffusion limitations.

Materials

Typically composed of high-surface-area oxides like gamma-alumina (γ-Al2O3), titanium dioxide (TiO2), silica (SiO2), or mixed oxides, often doped with stabilizers (e.g., cerium, zirconium) to enhance thermal and chemical durability.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Porosity	40-70%
Thickness	20-150 μm
Surface Area	50-300 m²/g
Adhesion Strength	>5 MPa
Thermal Stability	Up to 700°C

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 11841-1, ISO 19745, DIN 70070

Parent Products

This component is used in the following industrial products

Selective Catalytic Reduction (SCR) Catalyst

A catalytic component that converts nitrogen oxides (NOx) into nitrogen and water using a reductant like ammonia or urea.

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Engineering Analysis

Risks & Mitigation

Washcoat detachment under thermal cycling
Pore blockage from contaminants (e.g., sulfur, ash)
Thermal degradation above 700°C

FMEA Triads

Trigger: Thermal expansion mismatch between washcoat and substrate
Failure: Cracking or detachment of washcoat layer
Mitigation: Use compatible materials with matched thermal expansion coefficients; apply intermediate layers; optimize coating process

Trigger: Exposure to high sulfur fuels or lubricant ash
Failure: Pore poisoning and reduced catalytic activity
Mitigation: Incorporate sulfur-resistant materials; implement periodic regeneration cycles; use low-ash lubricants

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

Coating thickness ±10%, porosity ±5%, adhesion strength minimum 5 MPa

Test Method

ISO 11841-1 for coating adhesion, BET method for surface area, mercury porosimetry for pore distribution

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Washcoat

Manufacturer profiles associated with Washcoat.

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Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review

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Frequently Asked Questions

What is the primary function of a washcoat in an SCR catalyst?

To provide a high-surface-area support for active catalytic materials, maximizing NOx conversion efficiency while ensuring mechanical and thermal stability.

How does washcoat porosity affect SCR performance?

Higher porosity increases surface area for catalytic reactions and reduces diffusion resistance, but must be balanced with mechanical strength to prevent washcoat detachment.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Washcoat