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Titanium nitride
junior
Posted: Saturday, April 10, 2010 9:44 AM
Joined: 14/01/2009
Posts: 1026


Titanium nitride coating ......The piston rods on marine hydraulic cylinders all seem to be hard chrome-plated. The plating wears at the seal seat and the piston rod is ruined. I just watched an Italian fast motoryacht get hauled for inspection . After power wash her trim tab ram piston rods were perfectly bright " Gold " . Absolutely no marine growth adhered to the piston rods. The engineer told me its a Titanium nitride plating, similar to the hard lubricating gold color coating on a drill bit and lasts very long . The yacht went back into the water and disappeared over the horizon so fast that I didn't get a chance to identify the manufacture of these rams. Anyone with experience with titanium nitride hydraulic piston rods .?
Henning
Posted: Wednesday, April 14, 2010 2:57 AM
Joined: 01/06/2008
Posts: 1053


I've used Brycoat in Oldsmar Florida to spray it on before, I'm sure you can find someone in Europe who does it. It goes on in a plasma spray process. It's used a good bit in the aerospace industry so that's where I'd be looking. I think it's used on turbine blades in jet engines, so a major engine repair station, maybe GE or Rolls Royce has a facility in your area.

junior
Posted: Wednesday, April 14, 2010 11:32 AM
Joined: 14/01/2009
Posts: 1026


The big question is whether the Titanium coating is more durable in the marine environment. The present chrome plating on the stern door shafts has been lasting about 5 or 6 years. This will be the third piston replacement for one of the rams. How long does the titanium plating last ? 10 years ?
Chief
Posted: Wednesday, April 14, 2010 1:26 PM
Joined: 02/06/2008
Posts: 341


"The big question is whether the Titanium coating is more durable in the marine environment."

 

From what I have read, it may be, but the jury is still out. The coating is about 3 times harder than chrome but is much much thinner. Depending on the substrate, porosity of the coating may lead to corrosion beneath it.

It is being used on hydraulic rams more often because the chrome plating process is under fire from environmental regulators due to its toxicity and plating firms are struggling to find a replacement technology.


Henning
Posted: Thursday, April 15, 2010 12:43 PM
Joined: 01/06/2008
Posts: 1053


Well, I doubt it will last any considerable length longer. I haven't used it in an underwater application, I've used it in moderately high heat/pressure/wear applications (repairing expensive billet crankshafts). What the advantage to you would be (although this can be done with chrome as well) is that you don't "replace" the piston, you recoat it. In a submerged environment, I'd be inclined to try maybe a cerminil type coating  which is a ceramic and metal mix plasma sprayed on. It's giving pretty good service in aircraft cylinders especially on planes that sit around a lot between uses.

junior
Posted: Thursday, April 15, 2010 1:56 PM
Joined: 14/01/2009
Posts: 1026


Hmm....just talked to the Hydraulic ram guys in the Netherlands and both ceramic and titanium coating are available.. but.... special order ...12 weeks delivery time. Looks like replacement piston ,Chrome plated, with 3 weeks delivery time. I forgot to ask them. What is the purpose of chrome plating a ss shaft ? Higher working pressure ? I Have several ss shaft rams on the boat.
Chief
Posted: Thursday, April 15, 2010 6:18 PM
Joined: 02/06/2008
Posts: 341


"What is the purpose of chrome plating a ss shaft ?"

A 316 stainless shaft has a Vickers hardness measurement of around 200, chrome plating is around 900. So the chromed shaft is less likely to wear from abrasion and is less susceptible to corrosion.

 


junior
Posted: Thursday, April 15, 2010 8:46 PM
Joined: 14/01/2009
Posts: 1026


Cylinder pistons , funny question to be asking. The owner I work for operates a manufacturing business and is a prime supplier of precision steel products to the German Automobile industry. He manufacture millions of chrome plated Gas ram pistons for automobile hatchbacks and the internal components that make a diesel engine injector pump work. Perhaps I could just buzz the boss , ask for the technical department, find out whats going on and have it by Friday afternoon !!!!!!!!!!!!!!!!
Henning
Posted: Thursday, April 15, 2010 10:47 PM
Joined: 01/06/2008
Posts: 1053


Probably. Usually when I drop something off for plating or spraying I get it back within a week. 3 weeks is a bit long, but you're in Europe so you gotta expect it. 12 weeks is ridiculous.

junior
Posted: Friday, April 16, 2010 9:15 AM
Joined: 14/01/2009
Posts: 1026


Yup..things take longer. Same day DHL takes three days. Manana means next week, yesterdays Herald Tribune comes today, shops close between 1300 and 1600, 17 percent VAT on everything, paint even dries slower over here ..... . Gotta get used to it. Just called the life raft shop to check up on my raft re pack.......he replies..WHATS THE HURRY...its only been 4 weeks. Brought a Genoa to the sailmakers to have the leech sunsheild replaced and he looks at the Genoa , puts his hand on his forehead and says...Geez, that's a lot of work......Ordered a gasket kit from the MTU guys, two weeks pass so I stop by the shop to inquire on the status and he informs me that next time he speaks to the main office in he will ask..... Ordered two digital fluxgate compass repeaters, only had one in stock, 6 weeks delivery time for the second.... Yup......It the life.....
Anonymous
Posted: Thursday, July 21, 2011 4:14 PM
lewmar has started using titanium nitride coatings for their winches, http://www.myboatsgear.com/mbg/product.asp?prodID=1316 im thinking excellent replacement for bronze/brass cleats, fairleads, bells, fittings, etc.. would this be suitable for classic yachts? would it wear through with line chafe? is it expensive? cheers, A
 
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