Spin coating deposition on complex geometry substrates: Influence of operative parameters

- Coating thickness of model fluids decreases with the increase of spin time and speed.
- Fluids in a wide viscosity range can be deposited on cellular supports by spin coating.
- Ceria layers can be deposited on metallic and ceramic foams without pore clogging.
- Satisfactory results have been obtained in terms of washcoat adhesion.

An industrial spin coater was used to coat complex substrates for catalytic applications. Metallic open cell foams (20, 30 and 40 pores per inch, PPI) were coated for times up to 120 s using a range of spinning velocities (from 1000 to 3000 rpm). Water/glycerol solutions of different viscosities were used as model liquids to assess the influence of operating parameters on the deposition process. Coating weight (i.e., load) was found to decrease with rotation speed and spinning time, while higher coating loads were measured with an increase of viscosity and geometrical support PPI. Moreover, a process to spin coat acid-free cerium oxide slurries was developed to create a catalyst carrier on the three-dimensional substrates. Excellent control of deposited load and good adhesion performance were obtained.