Foam ceramic plugs because particles and deposits are intercepted throughout its tortuous pore network. Cleaning should match the deposit and protect both ceramic struts and any catalyst coating. Repeated plugging may indicate the selected PPI is too fine for the process.

TiO₂ coating changes alumina foam ceramic by adding active microscopic surface while also changing weight, pore openings and pressure drop. Final performance depends on coating loading, BET area, adhesion, light access and service conditions—not simply the presence of TiO₂.

Catalyst-carrier coating quality depends on loading, adhesion, pore openness and accessible surface area. Excessive washcoat can crack, detach or block foam pores, so coating mass should never be used as the only performance criterion.

Foam ceramic compressive strength is meaningful only when load is distributed properly. Flat support, correct orientation and avoidance of point loads are essential because the porous strut network can fail locally long before the average bed load reaches the laboratory strength value.

Foam ceramic pressure drop depends on PPI, porosity, thickness, velocity, fluid properties, coating and fouling. Never assign one universal ΔP to a PPI value without defining the operating conditions.