Summary for black oxide on stainless steel Discussion
Black oxide on stainless steel is not presented as a durability upgrade in this thread; the focus keyphrase here is black oxide on stainless steel. Sean Begley asked whether a black oxide finish on stainless is more or less durable than plain stainless, using Leatherman multi-tools as the example. Ted Mooney replied that his Leatherman tools can rust if left wet and unattended for months, but in normal use they do not rust and last fine; he said the black color is mainly a matter of appearance, not corrosion resistance. A later answer, apparently to a different project question, also cautioned against black oxide coating and dark colors, suggesting alternative materials such as nylon, PEEK, Ultem, or a plastic cap screw, though noting nylon is weak. Overall, the thread suggests the black oxide finish should not be assumed to improve durability over stainless steel.
Q. Does black oxide on fasteners; bolts, nuts, etc. help improve their resistance to galling? Either in 18-8 or 316 stainless.
R BRAUN
– Allentown, Pennsylvania
February 9, 2023
A. Hi R.
I’m not personally aware of any studies on that matter, but black oxide coatings are so thin that I don’t think they can have any effect on galling. In fact, I think they’ll wear off just about immediately in a wear situation.
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
Need quick confidential answers? $25
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⇩ Similar, related, Q&As — oldest first ⇩
Q. Hello everyone,
I’m wondering if a Black Oxide Finish (on Stainless Steel) is more or less durable then simple Stainless Steel. I don’t, unfortunately, know what kinda of Stainless.
I am particularly talking about the new Leatherman Multi-tools with a Black Oxide Finish vs their normal Stainless Steel tools.
Thanks,
Sean
Sean Begley
Electrical Engineer / Gadgeteer – Atlanta, Georgia, USA
April 26, 2010
A. Hi, Sean. I’ve had several Leatherman tools. Yes, they can rust if left really wet and unattended for months. But in normal use they don’t rust, and last just fine. The black color is a matter of which look you like, not corrosion resistance.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
Need quick confidential answers? $25
Need project assistance? $100/hr.
Q. So, to sum up your answer, the Black Oxide finish on the Stainless Steel does not, appreciably, affect the corrosion or wear resistance of the part?
A subtle follow on question, how is the durability of the Black Oxide finish itself compared to un-blackened Stainless?
Thanks,
Sean
Sean Begley
– Atlanta, Georgia, USA
A. Hi, Sean. A black oxide finish on plain steel has virtually zero corrosion resistance. It is usually waxed or oiled, and sometimes lovingly maintained with light oil in some cases such as with hunting rifles. Strip the oil off and the part will often flash rust in hours.
Perhaps one significant reason Glock firearms became so respected is that their Tenifer salt bath nitrided finish was such a huge improvement over black oxide.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
Need quick confidential answers? $25
Need project assistance? $100/hr.
Thank you Ted. That is exactly the kind of information I was looking for.
In this case, it looks to me like adding the Black Oxide finish will (of course) make the part black, but that it causes the part to require more maintenance then with the simple Stainless Steel finish.
Thanks,
Sean
Sean Begley
– Atlanta, Georgia, USA
Q. I’d like to put Stainless Steel (18-8) screws with black oxide on the outside surface of a medical scanner device. In other words, they’ll be exposed frequently to cleaning agents and bodily fluids.
Is that a good idea, or should I use screws with more corrosion resistance? My requirements are that the screws need to be black (or at least gray) and that they don’t show signs of corrosion (for aesthetic reasons) is this environment over time (10 years).
Victor Dzon
Design Engineer – Cleveland, Ohio, USA
October 11, 2013
 | A. Victor,
A. The black oxide has no corrosion resistance. However if you apply black anodizing, then the surface will be protected against corrosion in body fluids. This coating is bio-acceptable, applied for surgical instruments, with multiple sterilizations.
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