What is the difference between using an oven or an IR lamp to dry the coatings of fuel cells?

Question

I wondered how the morphology of the catalyst coating for fuel cells changes if it is dried either in a conventional oven (40 °C, 60°C, 80°C) or under an IR lamp. I am pretty certain that it changes, as Liu states:

"If the formulation and preparation processes of the catalyst ink, as well as the coating process are fixed, the drying process of the ink film deposited on the substrate will determine the morphology and structure of the CL. There are several influencing factors that should be considered, e.g., the drying techniques, evaporation conditions, solvent physical properties, or solid concentration in the ink." [1]

However, this paper does not mention IR lamp drying explicitly.

[1] H. Liu, L. Ney, N. Zamel, X. Li, Applied Sciences 2022, 12, 3776.

Answer 1

The mechanisms of heating differ. An Oven heats by conduction from the collisions of higher temperature gas molecules colliding with the substrate and from black body radiation. Volumes of low specific heats will heat faster than volumes with high specific heat. Infrared or microwave heating involves quantum changes in molecular levels. The original absorption of energy causes a population inversion in vibrational-rotational levels and no increase in temperature. The excited molecules relax losing energy by emission or collisional deactivation. The areas that heat first are the absorbers and the molecules in their vicinity. In both cases equilibration takes time [This is why it is a good idea to let microwaved liquids rest a while before disturbing them].

The difference among heating techniques are empirical. Different methods can give different results. The best comparison I can give is the difference in cooking results among an induction stove, gas range, electric stove, deep frying, hot air oven and a microwave oven. Each does things differently and has its place.

Infrared heating is the mechanism behind atmospheric warming. The Earth is the infrared heater. Gas molecules that absorb specific ir frequencies are the energy absorbers. The absorbed energy eventually becomes heat and is distributed about the Earth.