How to Specify Custom Foam Ceramic: PPI, Porosity, Material, Strength, Coating and Dimensions

An inquiry saying:

“Please quote foam ceramic.”

is not enough to define a product.

Foam ceramic can vary in:

• material;
• PPI;
• porosity;
• density;
• dimensions;
• strength;
• coating;
• application.

Two visually similar pieces may have completely different process performance.

A good RFQ should therefore describe both:

geometryandservice conditions.

1. Define the Application

Start with the function.

Is the foam intended for:

• gas filtration;
• liquid filtration;
• catalyst support;
• photocatalysis;
• adsorption;
• high-temperature processing?

The same PPI may not be appropriate for all these duties.

Application tells the supplier which properties deserve priority.

2. Specify the Ceramic Material

Possible materials include:

• alumina;
• silicon carbide;
• other specialty ceramics.

Material selection depends on:

• temperature;
• chemical environment;
• thermal cycling;
• abrasion.

Do not specify a material simply because it was used in an unrelated project.

3. State PPI

PPI describes pore-network fineness.

Typical decisions involve balancing:

• capture/contact;
• pressure drop;
• fouling.

If the existing product is being replaced, provide:

• confirmed PPI;
• sample;
• clear pore photographs.

Visual estimation alone can be inaccurate.

4. State Porosity if It Is Critical

PPI does not define total open volume.

If the project requires a particular porosity range, include it.

This becomes important for:

• hydraulic resistance;
• density;
• filtration capacity.

5. Provide Dimensions

Specify:

• length;
• width;
• thickness

for rectangular pieces.

For round parts, specify:

• diameter;
• thickness.

Include tolerances only when genuinely required.

Extremely tight tolerances can increase manufacturing cost.

6. State Quantity

Custom foam ceramic economics depend strongly on quantity.

The supplier may need to evaluate:

• tooling;
• production setup;
• coating batch size.

Prototype quantity and mass-production quantity should both be stated where relevant.

7. Define Mechanical Requirement

If the foam carries load, specify:

• minimum compressive strength;
• loading orientation;
• support arrangement.

Do not copy a strength value from dense ceramic.

Open-cell foam has a fundamentally different structure.

8. Provide Operating Temperature

State:

• normal temperature;
• maximum temperature;
• heating/cooling conditions.

A steady 800°C service and rapid cycling between room temperature and 800°C are different material problems.

9. Describe the Chemical Environment

Provide:

• gas or liquid;
• chemical composition;
• concentration where relevant.

Material compatibility should be confirmed before geometry optimization.

10. Provide Flow Information

For hydraulic evaluation, include:

• gas or liquid flow rate;
• frontal area;
• allowable pressure drop.

Without flow data, a supplier cannot responsibly confirm whether a chosen PPI is hydraulically suitable.

11. Describe Particle or Fouling Load

For filtration service, include:

• particle size;
• concentration;
• dust type.

This is essential for choosing pore fineness.

A fine foam selected without dirt-loading data may plug rapidly.

12. Define Coating Requirement

If a catalyst coating is required, identify:

• catalyst material;
• coating loading;
• adhesion requirement;
• firing requirement;
• BET area if relevant.

“Catalyst coated foam” is too broad.

13. State Whether PPI Refers to Bare or Coated Product

Heavy coating can reduce the effective pore opening.

The supplier should understand whether the specified hydraulic geometry is:

• before coating;
• final coated condition.

14. Define Documentation Requirements

Possible documents include:

• TDS;
• COA;
• dimensional inspection;
• material composition;
• strength report;
• coating data.

Only request documentation that supports actual project requirements.

15. Provide Existing Sample Information for Replacement

For replacement projects, useful evidence includes:

• dimensions;
• weight;
• photographs;
• material identification;
• PPI;
• operating history.

A physical sample can be especially valuable for unusual foam structures.

16. Avoid Specifying Impossible Combinations

Buyers may ask for:

• extremely high porosity;
• extremely high strength;
• extremely fine PPI;
• zero pressure drop.

These objectives conflict.

Engineering specifications must recognize trade-offs.

More ceramic improves strength but reduces porosity.

Finer pores improve capture but increase pressure drop.

17. Prototype Before Large Production

For custom applications, a small prototype or evaluation batch can help confirm:

• dimensions;
• pore structure;
• coating quality;
• fit.

This is especially valuable for coated carriers.

18. Final Production Data Should Be Confirmed

A generic catalogue gives a starting point.

The final order should confirm the actual combination of:

• material;
• PPI;
• porosity;
• size;
• strength;
• coating.

This prevents assumptions from becoming purchase specifications.

Engineering Takeaway

A foam ceramic RFQ should define what the product must do, not just what it should look like.