has anyone measured performance of silver plating solutions? - Page 1
Forum section: electronics / rf-microwave

author: coppercone2
author_rank: Super Contributor
timestamp: October 20, 2019, 02:09:16 am
content: So I am looking to protect my copper antenna.recommended for electronics usehttps://www.cool-amp.com/orderorrandom jewelry stuffhttps://jaxchemical.com/shop/jax-silver-plating-solution/I got the copper to a reflective finish now with a buff and abrasive compound, but I am wondering.... what the hell do you get for basically 3x the price?I don't expect to get a performance boost from this antenna (it needs a ding king more then anything) but.. why the price difference?

author: coppercone2
author_rank: Super Contributor
timestamp: October 20, 2019, 02:21:39 am
content: https://irp-cdn.multiscreensite.com/5a37792a/files/uploaded/CA%20MSDS-HMIS%20ratings.pdfsodium chloride, calcium carbonate, silver chloridehttps://jaxchemical.com/wp-content/uploads/2016/07/JAX-Silver-Plating-Solution-SDS.pdfAmmonia, Silver Chloride, Sodium Thiosulfateso is NaCl and CaCO3 better then aqueous ammonia and sodium thiosulfate for this?https://pdfs.semanticscholar.org/bab6/3be47615458cc3009a4149cb3067756955ab.pdfIs the sulfate maybe a problem since it reacts with silver?

author: coppice
author_rank: Super Contributor
timestamp: October 20, 2019, 02:47:13 am
content: A silver coating will improve the losses in most RF applications, but its a poor choice for protection. Unless the atmosphere is rather dry it can corrode quite rapidly. You may see parts completely blacken in a few days in some atmospheres. In most RF applications using silver coated parts some corrosion protection measure is needed. Conformal type coatings often spoil the RF performance, so you'll see techniques like the use of desiccants in sealed RF chambers.

author: coppercone2
author_rank: Super Contributor
timestamp: October 20, 2019, 02:49:14 am
content: will polished copper hold up better?its mainly for appearance rather then impedanceI just figured it would hold up better. it will change by so little and its not in a anechonic chamber or something so the random fields in the air will effect it more then anythingIf copper will stay brighter longer, I will keep it. I just thought it was more robust.Since I got it polished down pretty good now (needs a final pass with a green rogue) I don't mind just throwing some brasso on it once in a while. It looked like complete shit pulled out of a swamp and it worked fine. I figure it will work better looking like a trambone.

author: vk6zgo
author_rank: Super Contributor
timestamp: October 20, 2019, 07:26:55 am
content: Quote from: coppercone2 on October 20, 2019, 02:09:16 amIn the early days of Radio, copper was not as pure as it is today, & experimenters found that silver plating reduced losses.Moving right along to the late 1950s, silver plating to reduce losses had become the "received wisdom".A couple of EEs working in the Australian Postmaster General's Dept decided to find out just how much improvement was made.They made up "Tank Coils" for the PA stage of a transmitter, one set plain copper, the other silver plated.To their surprise, the copper coils consistently ran cooler!It turned out that copper purity had improved a lot, but the "biggie" was that the composition of silver plating had changed.The normal role for silver plating is to look attractive, & to be durable.Relatively pure silver plating, as used back in the early decades of the 20th century, did not meet these requirements all that well, as it was not easy to create a really glossy finish on it, needing to be regularly re polished by hand.It was also relatively soft, so polishing could remove material from the surface, unless the plating was quite heavy.The electroplaters added impurities which had the desirable effects of hardening the silver & rendering it easier to polish.It used less pure silver, so was cheaper.Win-win?But Oops! The added impurities increased the resistivity of the plating to greater than copper.This is why the special stuff for electical use is more expensive.

author: coppercone2
author_rank: Super Contributor
timestamp: October 20, 2019, 01:56:49 pm
content: do you think a bicone antenna out in the open would have a longer good looking life if it was coated in silver or left as highly polished copper?Assuming I get the cool amp brand. My copper sheet is from some jewelry supplier or something so it will probably benefit its not OFE Copperbut its basically a random band antenna, I just don't want a eye sore around.. i need to make a proper broad band pancake one

author: coppice
author_rank: Super Contributor
timestamp: October 20, 2019, 02:11:41 pm
content: Quote from: vk6zgo on October 20, 2019, 07:26:55 amIf the silver is applied properly it brings an improvement when the skin depth is really small, because its resistance is lower than that of copper. The problem is a lot of people do not deal with the coating very well. If you look in detail at many samples of silver plated copper wire that has been formed into a tight coil you will find the silver layer has been stretched to the point of forming a crazed mass of tiny silver islands on the outside of the coil. I know forming followed by plating improves this, but I'm not a metallurgist, and I don't know the details of getting a high quality result.

author: coppercone2
author_rank: Super Contributor
timestamp: October 20, 2019, 03:10:53 pm
content: I would imagine the best result is bend, destress, sand/polish, platemetal kind of sucks when its bent (try hammering a aluminum flatbar to make a bracket, it looks like it has wrinkles.. if you just get a home depot piece of flat bar and hammer it to a right angle in a vise you really see the metal is being 'worked').. i bet heat would improve this, but usually the point of bending is to save time and heating it is obnoxiouswhen I saw very heavy aluminum that was press formed into brackets (1 inch) it looked pretty shady on the interior side. like a roided old man body buildergreat way to make a clamp for a screw driver or vacuum cleaner hose that you can mount under a table etc, especially considering you can cut it with bolt cutters

author: vk6zgo
author_rank: Super Contributor
timestamp: October 20, 2019, 03:13:29 pm
content: The investigation the EEs carried out was formally presented in the "Telecom Journal of Australia", which was a well respected Engineering publication.Unfortunately, as it was a long time ago, there are probably no copies still in existence.I only saw the paper in reproduced form, back in the1960s.

author: coppercone2
author_rank: Super Contributor
timestamp: October 20, 2019, 03:15:38 pm
content: I can do VNA plots of this antenna before and after plating the exterior. Will take a while though.

author: coppercone2
author_rank: Super Contributor
timestamp: October 20, 2019, 03:27:53 pm
content: https://www.dxmaps.com/discuss/silverplating.html

author: Fraser
author_rank: Super Contributor
timestamp: October 20, 2019, 03:32:54 pm
content: I am just about to start some experiments with Bright Nickel electro-plating some battery contacts etc. Not RF, but I have seen plenty of Nickel plated brass and copper antenna parts in my time. Losses can be a consideration due to skin effect and nickels resistance (in some very high performance cases) but something tells me a thin coating of weather resistant Nickel is not going to be the end of the World for your antenna. Nickel plating can be effectively done with either a Nickel electrode brush technique or in a tank. The brush technique places a very thin layer of Nickel on the surface and is described as cosmetic as a result. That sounds like what you want and Nickel loves to coat copper !https://www.gaterosplating.co.uk/https://www.gaterosplating.co.uk/plating-kits/bright-nickel-brush-plating-kitMay be worth looking into ?Fraser

author: coppice
author_rank: Super Contributor
timestamp: October 20, 2019, 03:40:51 pm
content: Quote from: Fraser on October 20, 2019, 03:32:54 pmIf you try something like a nickel plated N-connector versus a silver plated one you will find the silver ones runs much cooler on day one. However, the nickel plated one will run at the same temperature on day 1000, while the silver plated one may have gone up in smoke on day 1000 if the atmosphere is humid. Places like Hong Kong, Mumbai and Singapore are killers for silver plated connectors.

author: coppercone2
author_rank: Super Contributor
timestamp: October 20, 2019, 04:46:44 pm
content: you know I think I will also try putting grease on BNC connectors and see how that effects things to 300MHz (my VNA).Is ultrasonic + simple green enough to remove dielectric grease for RF applications? (so I can clean my connectors afterwards without contamination). I was thinking to smear on barrel and put a tiny glob on the middle receptor.

author: helius
author_rank: Super Contributor
timestamp: October 20, 2019, 05:22:45 pm
content: Silicone grease is quite difficult to remove (the "universal contaminant") so if you are planning to fully clean it I would stick with a petroleum type grease (Cosmoline or No-Ox-Id would work).

author: coppercone2
author_rank: Super Contributor
timestamp: October 20, 2019, 05:29:58 pm
content: is there anything from home depot that would be good ?I can use this DChttps://www.minicircuits.com/pdfs/ZEDC-15-2B.pdf

author: IconicPCB
author_rank: Super Contributor
timestamp: October 23, 2019, 10:50:44 pm
content: Coppercone,We make printed circuit boards.Part of our process is electropolishing of copper to a high gloss copper mirror prior to electroplating.If you are interested in achieving a bright copper surface finish you too can use the electropolishing process....A mixture of nitric acid and alcohol is required.An initial current density ( may need to experiment a little bit) must be monitored for signs of reducing current.Principle of operation solution provides a copper etching environment with conductive path which is self healing as the surface roughness reduces. Copper surface roughness penetrates through an initial conductive barrier layer. As etching progresses current drops and that is the sign surface is polished.EDIT that should read PHOSPHORIC ACID NOT NITRIC ACID.... my mistake

author: coppercone2
author_rank: Super Contributor
timestamp: October 23, 2019, 11:57:19 pm
content: how do you monitor current? galvanostat?does it offer a better finish then abrasive compound on a buff? have you ever measured your process to a Ra number?any idea where the benefits would start from a microwave standpoint?maybe a test would be a stripline filter that is polished to various grades and put into a VNA? are the numbers similar to numbers given for stainless steel electropolish?It's nice to put on a dust mask and get some wipes and clean up the area and have waste suitable for a trash can (in regards to mechancial polishing.. nitric acid would need to give serious performance increase for it to be worth it on a hobby scale IMO unless you have a bit of cash for disposal etc. will it attack parasitic undercut on etched PCB?also, unsuitable for ceramic PCB correct (they will dissolve in acid)? possible to mask from nitric acid if you are trying to chemically 'hone' a controlled impedance trace on ceramic? or rate if reaction of substrate is slow enough to allow the copper polish process to occur before critical damage is done? how would the substrate reaction show up on your current measurement.. or do you only do it to less reactive epoxy substrate (I assume).

author: JohnG
author_rank: Frequent Contributor
timestamp: October 24, 2019, 03:17:29 pm
content: Cool-Amp:I have some, and I have used it for some small parts of a large transmission line resonator (1 m long by 10 cm OD, 50 ohms). It works ok, but it is a lot of work to apply, since you rub it on, and the silver layer is very thin. The reason for the latter was explained to me by a chemist, who said that the compound works because the copper reacts more easily with the compound. When you rub it on the copper, the copper displaces the silver, which deposits on the copper. Once the copper is covered with silver, no more reaction, and no more silver deposited, so you can't get much silver. I don't know how thick it ends up, but it's thin to be very resistant to corrosion.Nickel plating on RF parts:It adds loss, and the loss can be considerable as the frequency goes up. I'd be really concerned about losses on an antenna, where the currents tend to flow near the surface. A connector is a short part of the system, so the extra losses will be limited to the connector.Nickel has the added disadvantage that it is magnetic, and skin depth is proportional to (conductivity*permeability)^-1. Since nickel's relative permeability is high (> 100?), this reduces the skin depth a lot. At some high enough frequency (GHz), the permeability drops, so if you get high enough it may not be as big of a problem.John

author: IconicPCB
author_rank: Super Contributor
timestamp: October 24, 2019, 10:26:21 pm
content: Current is monitored by an amp meter...I have no way of specifying the surface finish.Surface roughness is to be thought as variation in electrical length of the path. As such it may contribute to skin loss( reduction in Q) and an uncertainty in electrical length important at higher microwave frequencies.We had been asked to fabricate a cavity strip line filter in Rogers multi layer structure.And while Rogers specify conventional multi layer pressing process to handle the material they also recommended a chemical surface treatment to enhance bonding.We did not have access to all materials ended up pressing the filter structure and producing functional samples however hole wall activation was compromised, the bonding between layers was porous and the finished product suffered from palladium ingress into the board.One way to enhance the bonding would have been to mechanically treat the copper prior to bonding however the result was skewing of filter performance and loss of Q due to the above mentioned effects on surface path length and skin losses.If You want to see the surface which is electropolished I can certainly put it through the process. May be a well known ( to You ) filter hand rubbed versus electropolished side by side shoot out?

author: coppercone2
author_rank: Super Contributor
timestamp: April 05, 2020, 02:35:43 am
content: I suppose I should update this thread in the interest of keeping everyone in doors.Ok, so do you have a tutorial or primer on electropolishing copper?The only process I am familiar with is electropolishing stainless steel using a conductive brush. I imagined maybe something with carbon wool or something too, or maybe a tank.Estimates on required power supply and electrolyte composition?

author: helius
author_rank: Super Contributor
timestamp: April 05, 2020, 07:10:25 am
content: Electrocleaning solution:Sodium carbonate 50gTrisodium phosphate 25gSodium hydroxide 25gWater 2000mLThis must be stored in plastic. Concentrated bases attack glass.Alternative formula:Sodium carbonate 75g/LSodium hydroxide 12.5g/LTrisodium phosphate 25g/LSodium silicate 12.5g/LCurrent density: 1 to 3 A/dm^2Polarity: 1 to 3 minutes cathodic (at the work)5 to 10 seconds anodicOperating temperature: 60 to 70 °C

author: coppercone2
author_rank: Super Contributor
timestamp: August 24, 2020, 07:45:27 am
content: how good are those current figures if you want to do work with some kind of sponge? can you work small areas like stamping a document?

author: StuartA
author_rank: Regular Contributor
timestamp: August 25, 2020, 07:49:27 pm
content: Quote from: helius on April 05, 2020, 07:10:25 amCould you just confirm what materials these solutions are intended for?ThanksS

author: helius
author_rank: Super Contributor
timestamp: August 25, 2020, 09:09:23 pm
content: Quote from: StuartA on August 25, 2020, 07:49:27 pmIt should work on all metals, but note that this will leave the surface activated. You need to passivate the work if no further processing is to be done.

author: StuartA
author_rank: Regular Contributor
timestamp: August 26, 2020, 12:59:11 pm
content: Back in the 1980's, I was involved in a detailed study of how best to pickle/passivate stainless steel to achieve optimum compatibility with the liquid rocket propellant dinitrogen tetroxide. After treatment by various methods, we looked at the surfaces with both an electron microscope (SEM) and a photoelectron spectrometer (XPS). Under the SEM, we could see that different pickling/passivation procedures resulted in different surface topographies. But when we looked at the chemical composition of the surface with the XPS, the composition hardly varied from one process to the next. Explanation - the final stage of each of the various processes was always the same; rinse off all the reactive chemicals with deionised water, while handing in air (~20% O2). Outcome, that final water/ air exposure has the final effect on the chemistry, we forget just how reactive water and air are and the test pieces all come out with about the same surface composition. We had a lot of fun doing surface chemistry, but time spent on the SEM and XPS is hard on project budgets!S

author: coppercone2
author_rank: Super Contributor
timestamp: August 26, 2020, 08:55:50 pm
content: Quote from: helius on August 25, 2020, 09:09:23 pmDO you know if the mass of sodium carbonate here is anhydrous or typical hydrate (before you add the water, what are you weighing out)?

author: helius
author_rank: Super Contributor
timestamp: August 27, 2020, 05:07:53 am
content: I believe it is given as the monohydrate. It shouldn't matter, though, there is only 18% between them. The carbonate acts as a buffer so it isn't critical.

author: coppercone2
author_rank: Super Contributor
timestamp: August 27, 2020, 08:03:30 am
content: Look forward to trying this soon. Can I try it with a sponge with similar results or do I need to setup a bath? I don't like chemical baths, mainly because I would need to make containers. All those chemicals are very cheap BTW, but it seems that you need to dispose of the phosphate correctly because its a environmental pollutant (another reason why I don't want to do a bath with large volumes, annoying to clean/evaporate/boil/etc).(I don't want to spend 10$ to buy more polypropylene jugs LOL :0)*interested in this in weld cleaning for stainless ATM. I know if you do a PCB you should probably make a tank.Also, do you know what the benefit of the silicate is in the solution? I have it, but I noticed stuff I make up with silicate in it, i.e. etchant with silicate and NaOH, it crystallizes a puck of glass(?) in the container after a while. I assume it slows the reaction down and temperature stabilizes it?DO you know how shelf life is effected with the silicate added?And what do you recommend for the electrode?

author: helius
author_rank: Super Contributor
timestamp: August 27, 2020, 07:25:49 pm
content: Trisodium phosphate is commonly used by painters to clean house siding, where it all washes into the watershed. It has minimal environmental impact and no special treatment is required. You aren't going to create a huge algal bloom with 100g of TSP...You could use a carbon or stainless anode. Carbon would be better if you are going to electroplate the work because of the possibility of chromium contamination from SS.https://orchid.ganoksin.com/t/electro-cleaner-for-pen-plating/34430http://web.archive.org/web/19991010051525/http://www.metalworking.com/dropbox/E-CLEAN.TXTSilicate is a flocculant, it attaches to debris particles and pulls them out of the bath. Probably it is less effective with brush methods. You're right that it may shorten shelf life.Also check the forums atwww.finishing.com, there's a great depth of experience there.

author: coppercone2
author_rank: Super Contributor
timestamp: August 28, 2020, 06:17:18 am
content: I wonder what a reasonable test would be to test the effect of the polish on a PCB.If strip line was made on FR4 board, could a polished and unpolished piece be evaluated by high frequency S parameters without ridiculously sensitive and precise equipment? And, would FR4 variance be low enough so the data could be trusted?Or would you need to etch it on ceramic PCB to eliminate dielectric variance? I think I read some where that things like PCB filters begin to be effected at 10GHz because of surface finish. I wonder what the least sensitive structure is that you could make to minimize etching inconsistency that would highlight the effect of surface roughness, in order to determine if the polishing does anything, and rule out other problems like minor mis-positioning of solder connectors/terminations, to verify if the process does anything to signal integrity from the standpoint of pure initial conidtion RF propagation (not corrosion resistance, longevity, or other factors that the polishing might improve from a 'mechanical durability' standpoint). So it would make sense to evaluate this on freshly prepared bare copper, or something coated with a electroless fresh tin strike (or something that is fast acting and puts a minimum layer on that will be consistant with exposure time only,(high process control).

author: IconicPCB
author_rank: Super Contributor
timestamp: August 28, 2020, 08:50:43 am
content: design a quarter wave resonator and look at the surface effect on Q.Say three identical structures, one in as supplied copper laminate, one in polished finish and one in surface roughened finish , say a fine grit scourer pad.

author: StuartA
author_rank: Regular Contributor
timestamp: August 28, 2020, 07:33:57 pm
content: Quote from: helius on August 25, 2020, 09:09:23 pmIf those solutions leave the metal surface in an "activated" state which has to be passivated, what would you use oncopperto do that? When you take the metal out of the cleaning mixture, presumably you have to wash the surface very well with de-ionised water to remove all traces of the reactive chemicals? What do you do after that?

author: coppercone2
author_rank: Super Contributor
timestamp: August 28, 2020, 07:41:45 pm
content: I think its activated because its super clean. Thats why I suggested a tin strike right after you get it to the surface finish you want. I think you need to laquer or coat it with another metal.. I don't think you can deactivate it any other way. I assume a non-even dielectric coat of laquer would mess with it.I think when you take PCB out of a ferric etchant tank they are also activated, the color right when its being pulled out of water is very unique.The coolamp would need to be, polished after its done, if you follow the directions, because it requires scuffing during application. The other solutions use inferior silver.So I think the choice would be a passivization layer that is ultra thin, and desposites insensitively to electric parameters (I don't think a filter will electroplate well).Maybe jewelry dip silver plating if not tin?Oh, and of course most PCB are just passivated with a silk screen, but since this project is working in the 10GHz regime, I am not sure how good of a solution that is.For experiments, even if tin is RF bad, it might be a good way to analyze the surface finish, if its done quickly with a fresh electroless solution. I am not sure if there is any other way to get a uniform coating that does not effect the surface polish other then electroless metal plating. And you might need to re-clean that and let it reoxidize?***The other recommendation I would have is to get a air compressor and blow dry the part after rinsing with as high of a pressure as you can get to dry the surface out.

author: coppercone2
author_rank: Super Contributor
timestamp: August 28, 2020, 08:11:17 pm
content: speaking of strip lines, I wonder what the surface finish on copper tape people use is. (fresh 3M). Maybe those tape filter prototypes have an advantage in this regard?also , this might be how to monitor the current to determine process stateI think it would be the same for a copper PCB. He uses H3PO4, but I got the chemicals for the bath listed in the thread. Wonder what the difference is. It seems difficult to get the 'curve'.Does anyone know if copper should have the same curve?

author: StuartA
author_rank: Regular Contributor
timestamp: August 28, 2020, 08:33:29 pm
content: I think activated means super clean, so, free of carbon (usually,'carbonaceous crap' covers pretty much everything in the World, which really is a farm-yard outside of a clean room) and free of copper oxide - but, as soon as you wash it with water in air to get the cleaning reactants off, I suspect that you'll form a very thin layer of copper oxide. We are talking about layers which down in the nm scale of thickness, but none the less, it is such layers that can make a big difference to a material, best example perhaps is stainless steel.I've never worked professionally on copper, but there must be a mountain of info about preparing it for plating and actually doing the plating. One of the things we found was that trying to clean corrosion test specimens using organic solvents was poor at getting off the carbonaceous crap. For ferrous metals, our favourite cleaning technique for test specimens was to use a proprietary cleaner called Decon-90 in an ultrasonic bath, which cleaned very well, but did not etch. It became a standard procedure in the UK nuclear industry.

author: coppercone2
author_rank: Super Contributor
timestamp: August 28, 2020, 08:45:11 pm
content: The good thing is those should not have an effect on microwaves. But I wonder at what frequency you start to get effects from that kind of oxidation in a way someone can measure at home.This is what I have in mind when thinking about this problemhttps://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.488.9435&rep=rep1&type=pdfThe only problem is, E8364B, at 60,000 USD on ebay. I was hoping those resonators that were suggested would make it more detectable (trying to cheapen the experiment so it will work with our zombies and swamp pull connectors).I have a feeling detecting anything nm thick with AC (not DC leakage) is going to be very expensive from the standpoint of semiconductor/conductor physics. This has mainly to do with skin effect right now, I think what you are wondering about is more related to thin film optics (if we are talking about wave propagation not general quality)?

author: IconicPCB
author_rank: Super Contributor
timestamp: August 29, 2020, 12:01:29 am
content: We polish our copper laminate prior to electroplating.We use a mixture of acid and IPA.IPA provides the the insulating layer and reduces chances to excessively etch copper away.There is also a characteristic current curve which resembles the first half of the curve shown in the video. Polishing done when the current drops ( due to alcohol in the mix ).This is a part of the hole wall activation process which is based on copper hypophosphite which through pyrolysis deposits copper nano particles on the hole walls.

author: helius
author_rank: Super Contributor
timestamp: August 29, 2020, 02:09:25 am
content: Activated means that metal atoms are exposed on the surface of the work, not covered by a protective oxide layer. Metal must be activated in order for electroplating to work, because the atoms deposited from the bath need to form metallic bonds with the base metal. Oxide gets in the way and makes the plating weak and mottled.Passivating is a finishing process that covers up the metal atoms with a protective layer, which can be oxide, nitride, phosphate, chromate, etc. Steel and aluminum should be passivated to prevent corrosion. With copper PCBs the usual procedure is to plate metal over the copper, such as with ENIG; solder over it, as with HASL; or cover it with stable flux-like corrosion inhibitor, OSP. Passivating the copper is not usually used because it would make soldering difficult.

author: coppercone2
author_rank: Super Contributor
timestamp: August 29, 2020, 02:59:09 am
content: you never gave the formulation of the phosphoric acid/isopropyl cleaner that you have good experience withI see its also very cheap and useful for metal work.What happens to electropolished vias?

author: helius
author_rank: Super Contributor
timestamp: August 29, 2020, 04:57:08 am
content: As long as the vias are mechanically sound they should be unaffected by electrocleaning, but their location may be too "shaded" to be effectively cleaned by the process. Ultrasonic will penetrate better.It's also possible to use alternating polarity for electrocleaning as well as with electroplating. The anodic phase will repel any loosely adhering metal atoms that got pulled onto the work during the cathodic phase, leaving a smoother finish. It's done for only a few seconds to avoid pitting the surface.

author: coppercone2
author_rank: Super Contributor
timestamp: August 29, 2020, 05:27:31 am
content: hmm, is there any application of AC balance here (dc offset)? and what do the frequencies look like this process?

author: IconicPCB
author_rank: Super Contributor
timestamp: August 29, 2020, 11:07:03 am
content: Activation deposits copper nano particles over all surfaces.Nano particles are embedded into the de-smeared epoxy surfaces of the hole walls.Nano particles are therefore desirable inside the holes as they for seed layer for electroplating.On the flat outside surfaces they would form a rugh finish plating if not removed ( polished off).So electropolishing prior to plating ensures a level smooth plating finish.

author: coppercone2
author_rank: Super Contributor
timestamp: August 29, 2020, 08:08:21 pm
content: Is there a hack to use voltage here? Like the nickel plate I have specifies a Current/Area, but it also says its just acceptable to use 2V and let it operate as powered by a voltage source.I.e. the range it gives is 10-20A/Sq-foot, or 2V (well a high current 2V but still). Makes it a little easier.Feels like its going to be difficult to figure out the current density you need unless you calculate the cad files area. Not a big deal unless you have old masks and no gerbers, or just image files saved.

author: StuartA
author_rank: Regular Contributor
timestamp: August 29, 2020, 11:12:29 pm
content: The amount of info on nickel plating on the internet is all but infinite, but you do see some variations in the conditions recommended, often in regard to the temperature and current density to be used. Of course, there are a number of different "recipes"for nickel plating solutions.Possibly better still, if you could source some, are theelectrolessnickel plating solutions. As the name implies, you don't need to apply a current, they just deposit nickel out of solution. I've used one proprietary product in the past and it was truly outstanding, but the company which supplied that is no longer trading. Unfortunately, this tends to be the kind of stuff where the minimum quantity they will deal with is a drum containing a few gallons.

author: coppercone2
author_rank: Super Contributor
timestamp: August 30, 2020, 03:18:58 am
content: lol, I tried this on a small scale, with a HP 3A linear supply, a sponge, the solution without silicate, stainless steel electrode. I put a slab of stainless steel inside of a glass tray and put a sponge on top of it and then poured a bit of solution on it.I attached the other wire it to a dirty ass copper scrap (small ~0.7mm thick sheet cutting that looks like a small slice of pizza) and it turned black in a pattern resembling asphalt after 30 seconds after being pressed into the sponge.Just a warning, you appear to need a half decent setup for this procedure. Or the temperature actually matters. Not sure if you can heat it up on a hot plate to 70C and dunk it once in a while if you are trying to work without a bath. And you probably need a sponge thats uniform, like a nice soft one, not the 'lava rock' like thing I have. I heard sizzling.I don't want to work on this until I setup a regulated battery powered power supply (dislike using mains equipment near pools of water, it makes me nervous. I try to minimize the number of things that are plugged in near ultra conductive salt solution)And it might also need to be cleaned from oxides first, the stuff I tried was the grungiest piece of copper you will see. Perhaps it needs to be buffed a little first to bring it to a copper like state. Good quality copper is a rarity because I use it up quickly.oh i know, i will try a penny

author: coppercone2
author_rank: Super Contributor
timestamp: August 30, 2020, 04:31:25 am
content: On a penny in submersion it works well, it came out with new shine. The sponge needs a greatly improved apparatus.BTW its cathodic, the cleaning process shown on youtube is anodic with phosphoric acid in most casesIf you do this on a PCB it would need to be carefully jumpered so you can machine the jumpers out of the circuit, not trivial at high frequencies that require precise PCB lengths. Maybe a small diamond burr would work. I noticed things cut with diamond have much nicer surface finishes in the same grit (i.e. diamond lapping plate leaves it looking like its ready for a metalurgical inspection if you do it on something, say a driver bit side).Does anyone have an idea about how to link up a complex PCB for electropolishing on the signal layer? Unless you do the photoresist yourself, its going to be difficult. Especially with SMD stuff. A ground plane is much easier. Doing a bunch of cuts is very labor intensive and adds alot of work to layout.Granted, unless you are doing a full on portable miniature spectrum analyzer, individual cans are not that bad. Things like DC routing can be ignored. And it would only be really beneficial in the LNA i think. Active antenna amp? I am suspicious that sticking the PCB on a buffing wheel with fine (green) jewelers polish (chromimum oxide) might have better results too.

author: coppercone2
author_rank: Super Contributor
timestamp: August 31, 2020, 12:36:29 am
content: what the hell is this solution doing. I put a wave guide piece in there (brass) , in a tub, partially submerged, the part facing the stainless electrode turned carbon black. The part facing away from it got polished impressively.

author: coppercone2
author_rank: Super Contributor
timestamp: August 31, 2020, 02:01:30 am
content: you can see the submersion level, one is the copper pipe the other is a waveguide brass piece.The black line is the water level line. Some of brass I cleaned up on the wire wheel, it does not get nicely polished like that. I wonder if maybe its malfunctioning because the waveguide couplers are made of a different material then the waveguide body.Why is it turning my waveguide black but working on copper? not suitable for all metals? something with tank /bath parameters?

author: helius
author_rank: Super Contributor
timestamp: August 31, 2020, 03:34:00 am
content: zinc and chromium ions reacting to form a chromate conversion material?

author: coppercone2
author_rank: Super Contributor
timestamp: August 31, 2020, 04:03:13 am
content: hmm, do you think it has a useful engineering use as a coating? Black brass? Its not super durable though. But for minor handling it seems to be as good as paint in some parts. I can rub it on my forearm with high pressure and there are no streaks. Like pressure across 1cm on the flange lips has a resistance of 0.2 ohms, wheras hard pressure on the clean part obviously is a dead short. SO its not super conductive. A part with a much much thicker layer reads 5 ohms on 1cm.SO I guess you can say the coating is somewhat conductive.. not good for safety ground anyway.The conductivity does not seem to change that much compared to the brass that is 'clean' but not really clean (looks like brass), in regards to light pressure with standard DMM test probes. Good coat for a door knob?Any why was it at first polishing the brass that was on the other side of the piece (not near the electrode)? At least for a while, if you leave it there for 1/2 hour it turns all black with varying thickness.

author: IconicPCB
author_rank: Super Contributor
timestamp: August 31, 2020, 07:54:48 am
content: Some PCB shops produce a board with BLACK OXIDE finish... variety of copper oxide producing a roughened surface texture. Soldermask sticks to it like the proverbial to the blanket.

author: coppercone2
author_rank: Super Contributor
timestamp: August 31, 2020, 09:10:44 pm
content: yes, based on my feel for paint, this would be a good bond strength increase.

author: coppercone2
author_rank: Super Contributor
timestamp: September 03, 2020, 03:01:01 am
content: this cleaning solution when dirty is still good for cleaning braze flux/burn off of stuff prior to painting, if you have left overs

author: bitter_mike
author_rank: Contributor
timestamp: September 16, 2020, 12:57:25 am
content: Hi coppercone,I do electroplating bath formulation for a living, so I can probably help with whatever you're trying to do. I skimmed through the previous posts but I'm not immediately seeing what you're trying to do. What are you shooting for here?

author: coppercone2
author_rank: Super Contributor
timestamp: September 16, 2020, 03:14:01 am
content: wanted to know whats going on with home radio electronics and platingoddball tangent? design considerations for having a go at microwave PCBs and generally increasing Q of coils etc

author: bitter_mike
author_rank: Contributor
timestamp: September 16, 2020, 10:52:07 pm
content: Ah. Well silver plating improves high frequency performance marginally, as long as you can keep it free of tarnish and other stuff. I think that's been covered in past posts.What has been less well covered is the impact of putting other coatings over the copper. It looks like there is some talk of nickel plating here and that will make things considerably worse at high frequencies (depending on your particular definition of "high" and how thick the coating is).As far as electrocleaning/electropolishing goes (they're a bit different) I don't think that would have any significant effect on signal integrity.For your microwave PCBs, stay away from ENIG. The Ni causes a good amount of insertion loss, though this may be tolerable depending on what you're doing.Just my thoughts.

author: coppercone2
author_rank: Super Contributor
timestamp: September 17, 2020, 06:44:18 am
content: no it does have an effect on signal integrity, thats why I look to combine the kool amp and the polishing, by definition the kool amp cannot be applied polished, infact some people want to exonerate ENIG and such, it may not be responsible for the losses people seem to measurehttps://www.microwavejournal.com/blogs/2-judy-warner/post/17127-keepin----it-smooth--how-surface-roughness-impacts-high-performance-pcbsit makes sense if you do ceramic PCB because the drills and substrates alone are very expensive for good quality, as far as PCB goes, and it seems that it might not be possible to apply the kool amp and then polish it, if the problem is underlying roughness, giving scrub plating a upper operating frequency regimehttps://www.linkedin.com/pulse/yak-shaving-judy-warner?articleId=6638124396731080704#comments-6638124396731080704&trk=public_profile_article_view(author has possible bias against roughness)

author: coppercone2
author_rank: Super Contributor
timestamp: November 08, 2020, 08:49:51 am
content: I have been playing around with nickel plating, it looks like the same black crap forms if you run current too high on nickel plate solution. The bottle I bought claimed that 2V is a safe voltage, but when I was running that voltage on a small power supply, it blackened my parts. When I reduced the voltage it worked fine but the plating flaked off (I got lazy and decided that the ultrasonic was too much.... You just can't tell this stuff with intuition and judgment very well... my previous nickel plating while going by the book worked fine). Also, that power supply needs to be calibrated because its my oldest HP unit. I am looking at making a battery powered one for safeys sake to minimize cabling near the solution to the hot plate.I would guess that I need to reduce current density with the cleaning solution. I ordered some glassware and repaired some clamps and such to make proper fixtures for electropolish/clean/plate and bring temperature control into the mix. If you think about it, it makes sense, because in my previous effort the part facing the electrode turned black (high current density) and the part behind it got polished properly, this is in line with how I understand the current distribution to look like. My setup is also very bootleg.

author: coppercone2
author_rank: Super Contributor
timestamp: November 14, 2020, 12:53:04 pm
content: I also wonder if this black burned copper (over current clean) can be used to increase dissipation of the trace while protecting it more so then solder mask, i.e. similar to black anodization of a heat sink.

author: helius
author_rank: Super Contributor
timestamp: November 14, 2020, 05:36:53 pm
content: I'm curious if the black finish happens with a carbon electrode. One thought is that you can increase the distance between electrode and the work by placing a baffle between them.