Parmigiani Tonda PF Micro Rotor No Date with Siena dial

Ressence Type 1 Round Multicolour

De Bethune DB Kind of Two Grande Complication movement side

Schematic illustration of one reaction cycle of the ALD process, using the trimethylaluminium (TMA) -water process to make thin aluminium oxide films as (simplified) example. There, the starting surface contains hydroxyls (OH groups) as reactive sites; Step 1 is the reaction of TMA; Step 2 is a purge or evacuation step, Step 3 is the reaction of water, and Step 4 is a purge or evacuation step (image courtesy Véronique Cremers, Riikka Puurunen, Jolien Dendooven/Wikipedia)