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"Using titanium anodes in a iron containing copper plating setup"
February 19, 2010
I am trying to setup my own small PCB plating station, for hobbyist fun only. I had the chance to run a professional PCB plating system before. From my experience and by reading I know the copper plating bath can have more problems/maintenance associated than a palladium activation chemistry.
While I was looking for suppliers the nearest one to me (Atotech) has this 'Insoluble Anodes' copper plating setup with a iron ions as additive which replenish copper ions from metal copper while plating. Since I do not intend to run the system more than once a month, this setup with liquid flow, pump, filtering could make my life easier, to start it each time. I can develop my own pulse rectifier. For my little requirements this system seems to do without using additives, avoiding some maintenance and source of problems if I don't use them right.
My question is if I can use titanium sheet 0.5-1.5 mm thick (ASTM grade 2, 7 or 12) as insoluble anode in a copper plating system with Copper sulfate 200 g/L; iron sulfate 60 g/L; sulfuric acid 60 g/L; chloric ion 40 mg/L; average current densities of 3 A/dm sq on both anode and cathode (equal areas).
The (vertical) setup I am thinking in consist in divide the bigger tank, making a small isolated 'container' at middle with the 2 titanium sheets, PCB is placed between them, the filtered plating liquid will flow from the bottom of the pcb, and jump to the side 'containers', above the titanium sheet. On the side 'containers' will be copper metal and a polypropylene filter from which the solution is pumped out.
I would like to hear your experienced opinion about if I can use titanium as insoluble anode (since it has both copper an iron ions on). If I can use a 1 micrometer filter or if 5 micrometers or larger is mandatory.
Hobbyist - Coimbra, Portugal
February 23, 2010
Thanks to finishing.com to publish my letter. I wish to add that titanium can't be used as anode because the passivation effect which I didn't know about when asked this question.
A metal mixed oxide (MMO) coated titanium dimensionally
stable anode (DSA), coated with Iridium, Ruthenium, Tantalum oxides for example MUST be used instead, if a insoluble anode is required. Or the more expensive platinum coated. But I am still learning about this.
- Coimbra, Portugal