We spoke with Jason Potts from Hubbard-Hall on the topic of electroless nickel and, specifically, five ways to extend the bath life of EN.
Tim Pennington: You're another new person to Hubbard-Hall. I know you've been in the industry for many years, many, many years. Where did you get your start?
Jason PottsJason Potts: I've been in the industry for 28 years. I started at a young age at a place called it's HM Quackenbush in upstate New York. I started there in production and moved my way up through into quality and waste treatment, and eventually, in the end, I was a general manager, and one day, we went out of business. It was just like that. It was unfortunate. While I was there, I was fortunate enough to develop a class at the local college, and a cool fact is actually, I'm on a handout from the local college sitting in front of an old X-ray 1010 machine, which is very old. So that's where I started. So, I spent 12 years there on the applicator side and 16 on the manufacturing side.
TP: With Hubbard-Hall, what's your specialty there? What are you an expert at?
JP: My position is product manager. I have experience in all metal finishing processes. I would say my most experience has been electroless nickel and I think that's why we're here to talk about.
TP: The topic is ways to extend bath life. Let's start with the very first premise: what are the reasons that shops need to dump their bath? What's wrong with it? What's happening with it? Why are they dumping the bath?
JP: Let's look at the difference between electroless nickel and electrolytic. So the easiest way to explain it is to take an electrolytic bath, whether that'd be nickel, copper, or chrome; those baths will last 20, 30, 40, or 50 years. Those baths don't really generate any type of byproduct. With electroless nickel, you make it up, it makes up six grams per liter of nickel, and you make up 30 grams per liter of hypo. For every metal turn, a metal turn is the add back, or let's just say a metal turn, you'll produce 30 grams per liter of ortho for every metal turn. So, on a new bath, you have six grams per liter of nickel, 30 grams per liter of hypo, and at one turn, you have 30 grams per liter of ortho. At a 10-turn bath, you still have the same six grams per liter of nickel, 30 grams per liter of hypo, and 300 grams per liter of this orthophosphate that forms. Plus, you have sulfate in there. So, what happens to the bath is that it becomes viscous, slows down, staining, cracking, pitting, and everything that can be detrimental to a finished part, especially in Salisbury.
So if you don't have the right amount of hypo, you don't have the right amount of electricity, and you're going to get a slow plating rate.
TP: What makes a bath slow down? And I guess my premise question is, can they catch that the bath is slowing down or just see some parts that are not looking right? Do they catch that, and then what's making it slow down?
JP: You could catch it. In a typical EN bath, if you're doing standard mid-phos, you're going to go eight metal turns; you can predict your eight metal turns based on the square footage you're running. You're going to know that throughout that time, it's going to slow down. So, what makes it slow down? There are four parameters that will keep the bath at the speed that you want it to keep. You have temperature, pH, your nickel, and your hypo concentration. You can keep those all within 90 to 100%, but as the bath ages, you're going to have contamination. That contamination slows the deposit down, and there's also, on top of that, you can have contaminants like nitrates, zinc, which we may talk about, chrome, which is detrimental to the bath, and other metals and some metal stabilizers that can slow it down.
Watch the video: Episode 13: Electroless Nickel: 5 ways to extend your bath life - Video Episodes, Season 1
Staying on Top of the Bath
TP: It sounds like if people aren't staying on top of the bath if they're not really documenting and doing some proper maintenance, they're going to have some of the bigger issues that you've talked about of just having to dump it more often.
JP: Absolutely. EN takes a lot more control of an electroless nickel bath because you have no electricity. Hence EN, electroless nickel. So, your electricity is your hypo. So if you don't have the right amount of hypo, you don't have the right amount of electricity, and you're going to get a slow plating rate, or you might change your parameters in a bath enough to where you can change the percent phos in the deposit and have failures 'cause you're going to certify whether you want to plate 9% phosphorus or 11% phosphorus and you need to be within that range. So, without controls, you're not going to have that. With a standard electrolytic bath, you're going to put the part in; you're going to look at the square footage; you're going to put your ASF where you need to be, and go for a target thickness. Pretty much all of your additions have brightener feeders. With electroless nickel, your add-backs have all your goodies in them, I would say.
TP: Let's add another conundrum: I know aluminum actually causes more problems than EN baths, right? So, what is different about processing aluminum, and why is that caused? What's the driver of people having to dump baths prematurely?
JP: Aluminum loves oxygen, and when it does, what happens is that it oxidizes, unlike steel. Steel, you could go through a standard elec, soak clean, electric clean, an acid activator, and right into the EN. With aluminum, you're going to go through a soak clean, an etch, and then you're going to diox and then you're going to zincate. What zincate does is protect aluminum from oxidizing. Oxidizing causes blisters. So, when the part goes into the bath, it has a very thin layer of zinc on it, and into the bath it goes, it strips that zinc off. It immediately starts to plate electroless nickel, which stops the oxidation from forming. As the bath ages, now you're putting zinc in there. So, zinc's, number one, that's a contaminant. Bathe ages, and the bath is going to slow down as it ages. So, your activation slows down, and as the bath ages, your total acidity also increases. It's not going to be because of low PH's total acidity. So, what happens is you take an aluminum part, you start going in, say you're at four metal turns, you put the part in, the zincate strips at such a fast rate, but the initiation slows down on a nickel, and it leaves that minute second for oxidation to form and you get blisters. Therefore, typically, on an aluminum bath, you go four metal turns. You can do an elklan strike ahead of it to where the zinc is mainly staying in the rinses beforehand after you strip, and you can get some more life out of the bath, but it has a finite life. It's only going to last between four to six metal turns with aluminum.
TP: It's funny that you were talking about contaminants earlier. What should platters look upstream for that could possibly be causing problems that they're bringing into the tanks? I guess any of those processes that are happening. You mentioned a lot of steps that are going on there, but what are some things that should be looking at that could cause problems?
JP: What most shops typically struggle with is water. All right? So, you want good rinse water, and if you don't have good rinse water, whatever you're pulling out in the salt clean is going to go into the rinses, or the electro clean, or the acid will go into the rinses. In those rinses, you could have organics, metals, and oils. Any of those can be contaminants, especially when you get into any of these stabilizing metals. You get a stabilizing metal that gets into a rinse, it gets into an EN bath, over stabilizes it, then you have edge pull back, you have blisters, an array of things that you just don't want. So, you really want to make sure your rinses beforehand are as clean as you could possibly get from what your waste treatment can allow you to handle. You obviously don't want to overflow or go after your waste treatment at that point and have issues there.
TP: It's something I think a lot of people maybe don't often look at. They're just looking at the bath sometimes and wondering what it is instead of really going through the process and seeing kind of a cause and effect of what's happening.
JP: It's always the bath.
TP: And it usually never is.
JP: It never is, usually.
Minimize the Chances of Plate Out
TP: And you mentioned particles in the tank that can become plating sites, I guess, plate out the tank. Explain that to us and what shops can do to minimize the chances of that happening.
JP: With electroless nickel particles, it's a common problem, especially when you get into the high-build areas. When I say high build, you're talking 2000s to 10,000s, and with particles, they can settle on a shelf area. So, at the top of a part are very minute particles. The particles could come from something as simple as a sandblasting operation being just 20 feet away, which is bad, or a Ford truck going by and dust coming up, and those particles go into the bath, and those particles actually co-deposit. A lot of times, the ceiling has hoist systems up, and it's bouncing, and it's a plating shop. Plating shops are rusty. It's hard to stop that. So, you get particles in there, and they'll rest on top of the part. It's typically on a shelf area. And you can cause blisters, roughness, and all kinds of what they call snowflakes or haze on top of parts. The bath is designed, it's chelated, and it's wet enough to handle those particles. There's another thing you can do, too, such as a work bar agitator. You can add a little more air, but you have to be careful with air because that's a stabilizer, too. You could do inductors and try to push the solution around. So even though there are particles that are definitely going to come into the bath, there are things you can do to fix that, and a lot of it would be just filtration. You probably need to filtrate 10 to 20 times per hour in one-micron filtration. Not many shops do one micron, and they use bag filters, too, as opposed to cartridge filters. That's the better filtration for particles.
You can do everything possible to make sure it's right, and you're still going to have issues. It's just the way it is.
TP: It definitely can cause a problem with that. One other issue let's talk about salt spray testing because I know it's called out in many specs, but I understand that EN has kind of a difficult time achieving their requirements consistently. What can be causing this and what do platters have to do to make sure that they're meeting the specification with that?
JP: If you have another hour, we could talk about salt spray a lot. That's near and dear to me. The salt spray has been an issue for years. The problem with salt spray is that when you talk about salt spray, you're typically taking a four-by-six queue panel. You're plating it in a perfect environment; whether it be a lab, perfect loading, or perfect cleaning, everything is right where it should be. You go in the salt spray chamber, and you pass, sometimes. You could do it 10 minutes later, thinking you're doing the same thing and it's going to fail. And then you throw this in there. You have customer parts that don't even look like a panel, and they want 1000 hours or 100 hours, whatever they might be. It doesn't even look like the panel that you're trying to pass. So, with salt spray, it comes out, again, we'll go back to everybody saying, "Well, it's the bath." It's probably not the bath. It's probably the way you're operating the bath and what you're doing beforehand. A lot of times, it's cleaning. Cleaning is critical. Cleaning of a panel or parts is very critical because you have to get the soil and oils off of it. You have to make sure it's not etched. You don't want to etch it. Your panels themselves you can buy different panels that have different surfaces on them that can cause failures. And then after that, you have the bath. You have the bath. If the bath is brand new, you don't want to run a panel on a brand-new bath. You have to break it in. You want to be at a quarter metal turn. You want to have the proper filtration. You don't want to have the particles. Your post-treatment has to have good, clean rinses. And then when I say all this has to be like this, a perfect ... or loading. Loading is another example. Under loading, you're going to have heavy metal or metals; I should say, metal stabilizers that will attach to edges of the part or places that would be a low current density area if there was electricity. And in that area, you're going to fail in a salt spray chamber. So, to pass salt spray, you really just have to think about, in my opinion, what you're doing upstream and control that bath. Do everything as best you can upstream, including the cleaning and the rinsing, and then make sure the bath is right where, typically, you want to run at about 90%. And there are different salt sprays, too. Obviously, you're going to want to; they're typically shooting for 100 hours. The high phos is 1000 hours. Like I said, you can do everything possible to make sure it's right, and you're still going to have issues. It's just the way it is.
TP: Just the way it is. Always going to be a battle with those.
JP: It's a battle.
TP: It's very technical, and you have to pay attention to it. Not just anybody can do it. It takes training, and it takes expertise, and it takes the right chemistry and the right setup and really the know-how, like you said, of looking upstream and making sure that you're not hurting the bath with things that you may be putting into it, correct? Those things could be happening if you're not paying attention.
JP: Yes.
5 Things Platers Cabn Do to Better Manage EN Baths
TP: I know we've talked about a lot of the problems that would cause platters to prematurely dump their baths. So, again, let's recap those five things that platters can do to really be able to manage their EN plating baths a little bit better.
JP: The five most important ways that I feel that you can extend the bath are as follows: The number one is control. You need to control the parameters, nickel, hypo, PH, and temperature. Those parameters need to be kept in control. If you don't keep those in control if you were charting it, you'd have a saw effect, and the bath is going all over the place. That can cause plate out. So, control is number one. Number two is your rinsing. Make sure you have good rinsing coming before the bath itself. You typically want to use DI water. Some shops have DI water and RO water. Some shops don't, but the cleaner the rinses are, the less contamination you're going to bring into your bath. Number one, I probably should back up to it because before you put the bath in, you actually passivate the tank itself and all of the plumbing. So, with passivation, you're dissolving the nickel with a nitric acid. On top of that, you're putting a passive film on a stainless tank, which stops it from plating out. If you don't have a good nitric, you will start plating out immediately. I've seen it happen many times. I'll get the call and say, "Hey, I put a brand-new bath in, and it's plating out immediately." So, make sure the nitric is good. Filtration, good filtration. You don't want to make up a bath and have an old filter on there or something where you get these little BBs in there, and you're getting plate out, and you're not capturing the particles. If you don't have good filtration, if you're not filtering 10 to 20 times an hour, then you're not really filtering that bath. That bath needs to be filtered.
TP: And you said not to use the bags but instead to use the cartridges. Is that what you were saying?
JP: Use bag filters. It's the easiest to change to look in there and see what you're catching. The surface area, and typically the bag filters you want to keep out of the tank. Some tank setups have bags inside of them. I don't like that because, number one, you're taking up real estate. Number two, you're putting something in there that could plate. Anything can plate an EN bath if it has an active spot. If you get a little bit of nickel or if you touch a piece of steel onto that bag, you're going to start plating out. And then one of the other things is idle time. And we see this a lot. When baths idle. If you say you start up a bath, it's got to be 190 degrees. All right. You've got your six grams per liter of nickel and 30 grams per liter of hypo. What happens is your hypo starts to break down, and you build ortho. And then your stabilizers might break down a little bit, and then there's an imbalance. So then you start to make your additions of one-to-one. So, if you had to add a gallon of nickel and a gallon of a hypo, as you go through the bath life, your hypo could drop, and your one-to-one ratio is no longer there. And if you don't check your hypo as a separate test, you could run that ratio off too long, and you could have premature plate out or other issues.
