Chrome vs. Electroless Nickel Plating Comparisons

A. I do not think that it is going to make any difference with a 2 to 5 tenths thickness. Neither coating will do much. Lubricity will be close, but it depends what it is running against.

Chrome will have a little greater tendency to chip with continuous impact loading. Neither will offer much corrosion resistance.

Chrome is slightly harder.

With a rockwell that low, hydrogen embrittlement is virtually no factor.

A. Hi Janice. Hard chromium is harder, more wear resistant, and offers lower friction than electroless nickel. Electroless nickel, though, is far more corrosion resistant than hard chrome.

If you can get the hard chromium plating at a savings sufficient to make it worthwhile, I'd consider it, depending on the real corrosion situation. But I would not make this change unless there is a substantial reason to do it, as opposed to an abstract reason like the theoretical superiority of hard chrome in wear situations.Good luck.

A. What Ted is suggesting is right. If chromium is found necessary (and worth the cost), I would suggest applying a thinner layer of it on top of the nickel to provide double protection.

A. I agree with Ted that chrome has poor corrosion properties. You may want to consider one of the "composite electroless coatings" such as EN/Silicon carbide if you want these slides to last indefinitely.

A. You can also specify sulfamate nickel, with hard chrome over the sulfamate nickel. A typical nickel thickness would be .0005" - .001" followed by .001" of hard chrome. This will give you the hardness along with much better corrosion protection than straight hard chrome.

A. Electroless nickel is nowadays replacing hard chromium.If you want lubricated coatings you can opt for electroless nickel-PTFE composites.En corrosion resistance and hardness is more or less same to that of hard chrome

Q. We have decided to test Electroless Nickel, instead of Hard Chrome, we are looking for advice on what to look for technically that we are getting high quality plating, how should we cheek hardness on the 15 MM diameter shaft.

With thanks,

A. Dear Arik,

Electroless nickel you will be used instead hard Cr , but with following thermal treatment up to 250 °C during 2-3. This procedure is allowed you to obtain microhardness of nickel similar to Cr. For check the quality of nickel coating you have to prepare cross-section and test microhardness, not hardness.

A. Sounds to me like you don't have details of the actual pre-process. But you should be able to grind your part to size without polishing. If you have capabilities for Precision Grinding, you can hold a mirror finish or a 32 rms or whatever you need on hard chrome or nickel.

A. Electroless nickel has a slightly different colour to electrolytic nickel, so its IR reflectivity may be affected. However, you could use electroless nickel to build up a layer and then plate it with a bright nickel. Are you currently using a chromium layer? If so, you may not need to thicken with electroless nickel as chromium is usually only very thin and you can use a direct electrolytic bright nickel

A. Hard chrome is essentially not corrosion resistant like electroless nickel because it is invariably cracked. The cracked areas can rust.

A. It depends! Gas could mean natural gas or methane or propane or it could mean gasoline or diesel fuel or even crude oil.
It is much harder to get a very uniform coating on a ball with chrome than it is with electroless nickel. Chrome should not be a problem for low corrosive applications, but could be a big problem for something like sour crude oil.
For optimum, you might want to specify a high "P" EN or a boron EN.
Finally, thickness has a great deal to do with wear and corrosion resistance.

A. Hi Craig. Hi Peter. Hard chrome plating is wear resistant and low coefficient of friction but not particularly corrosion resistant because it is always cracked and, even if the chrome doesn't corrode, the underlying iron is somewhat exposed.

Electroless nickel is a barrier layer coating which is not only corrosion resistant but impermeable (if it's thick enough and well enough done), so the underlying steel is not exposed to the corrosive agents.

Regards,

A. A good quality, thick, high phosphorous electroless nickel coating, though softer than chrome, will resist corrosion much better and harden with time giving a good life. Most frequent causes for premature wear are not the plastic resin itself but poor maintenance practices when cleaning the dies, foreign particles in the raw material or carbon debris from burnt resin in the barrel. Also, the complexity of the internal geometry of extruding dies and the consequent need for special fixturing to strike them properly, frequently lead to the plater omitting this important step and subsequent problems with the adhesion of the coating. Search for a professional mold and tool plater.

A. Hi, Jignesh. Electroless nickel is far more corrosion resistant than hard chrome. Plus it tends to go on in an even thickness, whereas chrome plating doesn't. But the thing is, we really can't compare finishes effectively without knowing the application.

It's a bit like asking whether you should travel by rail or by ship, cousin. The entertainment is better on a ship, but that's irrelevant if you're going from Los Angeles to Las Vegas. A train is faster and the rhythm of the rails is more soothing than the wallow of a ship, but no help to know if you're going from LA to Hawaii :-)
Please tell us some details of the application you have in mind. Thanks!

Regards,

Q. Thanks Ted. Being more specific on application, I would mention the ferrous base material (mild steel or EN series steel) being used for plastic extrusion die part working under temperature range of 160-250 °C is to be coated with suitable coating. Adding to it, surface finish does matter here.

A. Hi again, Jignesh. You will get a more conformal coating, easier, and less expensively with electroless nickel. It will also be corrosion resistant, which may be important according to Guillermo's response above.

You might review this suggestion with a plater who offers both processes. Best of luck.

Regards,

A. EN plating of tool steels requires an initial highly acidic strike to activate the surface and promote adhesion. This step is electrolytic, so it will not reach internal surfaces unless adequately fixtured. Indeed it could even do the opposite. G. Marrufo-Mexico

? Why not electrolytic nickel?

A. Good day David.

Have you considered another base material for your nozzles, as you require a couple of months of use? SS, Ti, etc?
I am having difficulty with the brass being plated with hard chrome. Is the chrome deposit within the nozzle of sufficient thickness to deal with corrosion and abrasion? The chrome/electroless is a very hard deposit, but the underlying substrate as brass is very soft.
"Build a better mousetrap, and the world will beat a path to your door."
Happy hunting.

Regards,

A. As the old saying goes: You can have it cheap, or you can have it good. Choose one.

Option 1: Make them from tungsten carbide and they'll last for an eternity.

Option 2: Make them from nickel plated brass and they will last a while and will be cheap.

Option 3: Make them from heat treated alloy steel and hard chrome plate them at least .0005" thick and they will last a long time and will cost less than option 1 and more than option 2.

A. Hi Jagdish. Electroless nickel is superior to chrome plating in a number of applications but unfortunately the rule is that nothing can replace anything else without an exact understanding of the particular situation. For example, to the best of my knowledge (I hope my knowledge on this is dated, but I don't think it is) it has not been successful in replacing chrome plated hydraulic rods despite decades of intensive and expensive efforts. But you can certainly try it for your applications. Good luck.

Regards,