Page 38 - PCMI Summer Journal 2021
P. 38
An Overview of the Operation of Ferric Chloride Regeneration Systems in Photochemical Etching Machines
Presented by: Kirk Lauver, the Marketing Specialist, Chemcut Corporation, US
7/27/21
14
• The Hydrolysis Of Ferric Chloride:
FeCl3 + 3H2O è Fe(OH)3(aq) + 3H+ + 3Cl-
• Ferric hydroxide does not precipitate if the equilibrium is maintained or if there is excess (i.e. Free Acid) HCl in the solution.
• The HCl concentration affects the etching rate, the roughness of etched surfaces, the solubility of dissolved metals and the ORP value.
15
pH Electrode Requirements Range 0-14
Internally Pressurized (12 Bar)
Double Junction
Electronics must allow negative pH values, most lab and general purpose pH meters do not. Industrial meters and instrumentation are available for pH ranges of -2.0 to +16. Check before you buy.
Must be verified by titration
Issue 137 August 2021 PCMI Journal 38
