Antimony Additives

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MolaKule

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Antimony Additives
By MolaKule


This white paper discusses the basis of Organic Antimony Compounds as additives in Motor oils, Gear Lubes, and Greases.

Many additives are defined as “Multifunctional Additives” because they perform more than one function in a lubricant. One of the most well known additives, Zinc Diakyl dithiophosphate or ZDDP, is one of those additives. ZDDP performs as an Anti-Wear (AW) additive, a mild Friction Modifier (FM), and as an antioxidant. Organic compounds of Moly dithiocarbamates (MoTDC), also function in the same manner as ZDDP, but at higher temperatures and pressures. Boron (to be discussed in another white paper), can be used as an anti-wear additive and as a detergent component as well.

Then there is a class of additives which are also multifunctional, but perform only as AW additives and as Extreme Pressure (EP) additives; these are generally found in Gear Lubes and greases. They impart surface protection under extreme contact pressures and shear by virtue of laying down a surface film that prevents galling and other types of wear. These are the Phosphors, Sulfurs, Borons, and Nitrogen additives found in gear lubes and greases. Chlorinated hydrocarbons perform the AW and EP functions as well, but the decomposition of these compounds to hydrochloric acids, and their environmental impact, has led to the much reduced use of these additives.

Organic antimony compounds such as Antimony diakyl dithiocarbamates (sometimes denoted as SbDTC or ADD), is another one of those multifunctional additives, but is lesser known. ADD’s have been both bench tested and field tested, and have been found to perform the following roles:
1. Anti-scuffing (EP) agents,
2. anti-wear (AW) agents,
3. oxidation inhibitors
4. copper-lead corrosion inhibitors,
5. rust inhibitors.


There five main alkyl groups of SbDTC’s, and they are the n-butyl, the Amyl, the Hexyl, the 2-Ethylhexyl, and the Decyl groups. Chemically, the structure is composed of three alkyl molecules consisting of one nitrogen atom, two sulfur atoms, and one carbon atom, bound to one antimony atom. Anywhere from 10% to 17% antimony is contained in the dithiocarbamate structure, which has been found to be the most stable of all the antimony additives. Of the five groups, the Amyl and Hexyl dialkyl dithiocarbamates show the greatest resistance to welding, galling, and scuffing when subjected to Timken Loads.

When the percentage of SbDTC’s are increased from 0.5% to 3% concentration in a SAE 90 weight gear oil, the Timken weld increased from 160 lbs. to 355 lbs.

In greases, the SbDTC’s perform the functions of an EP additive, an anti-rust agent, and as an anticorrosion additive. Marine greases usually add SbDTC’s, since salt water corrosion is inhibited. Marine vessels and boat trailer bearings thus benefit from this additive in greases.

While some EP and AW additives show poor thermal stability, SbDTC’s do not. This is why they have advantages in motor oils as well. SbDTC’s in motor oils prevent bearing loss, low top ring deposits, and low ring wear. Camshaft lifter scuffing is almost zero when 0.5% of SbDTC’s are added to motor oils.

As with MoTDC’s, these organic antimony compounds also act synergistically with ZDDP compounds in motor oil. It is believed that sharing of the sulfur and phosphorus atoms contribute to the creation of surface films composed of layers of ferrous sulfate and ferrous phosphate, with the organometallic components depositing a plastic layer of antimony and zinc sulfates and phosphates.

So SbDTC’s are indeed multifunctional additives that contribute to the reduction of wear by acting as AW and EP additives, while preventing oxidation and corrosion inside engines, gear boxes, and bearings.

[ May 17, 2003, 12:59 AM: Message edited by: MolaKule ]
 
Thanks Molakule for this and all of the other articles you have written and posted. The technical expertise you have shared with us all has been very helpful.
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[ May 17, 2003, 03:46 AM: Message edited by: Sin City ]
 
MolaKule, Thanks for the info. I have been using your recommendation of 1oz per quart of #132 with Mobil1 10W-30. Anyway to calculate or guess the percentage of ADO?

Thanks again.
 
There would be about 25 ppm of Antimony or ADD if you added the full pint of 132 to 4 quarts of oil, which I do not recommend. 8 0z. or less per 5 quarts of 10W30 is my recommendation. For light 10W30's, I prefer to mix 132 and Lube Control in a ratio of 3:1 and then add 4 oz of the final mix to 4-5 quarts of oil.

With the newer ADD's, it doesn't take much ADD to make a difference in motor oil, GL's, and greases. Less than 0.5% is usually required for MO's.

[ May 18, 2003, 11:14 PM: Message edited by: MolaKule ]
 
We all need to be paying Molekule for contributions like this to BITOG ! Thanks Mole !

"those that have ears to hear, listen " .

This is good stuff, dudes.
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From an unbiased source!

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[ May 18, 2003, 11:41 PM: Message edited by: Terry ]
 
Molakule, Thanks, I guess I will have to look up Lube Control. I have never really understood it purpose or use, but you and others seems to like it.
 
I have no knowledge of Synergen's oil or treatment having antimony in it.

If you could send me some Synergen additive, I'll see that it gets tested. Send me a note on a PM and I'll send you the particulars.

Coastal Marine Grease, Luboron Marine Grease, Amsoil Red Spray Grease, Amsoil Fifth Wheel Spray compound, and most of Schaeffer's lubes are the only ones I have knowledge of that contain antimony compounds.
 
What's a good level of antimony to look for on an oil analysis? Is it a readily available test?
 
After several requests we are going to start running Antimony as part of our standard analysis. Can someone tell me the expected value? I need to order the standards. MolaKule mentions 25 ppm back in 2003, is this what's being used today?

Stinky
 
quote:

Originally posted by Stinky Peterson:
After several requests we are going to start running Antimony as part of our standard analysis. Can someone tell me the expected value? I need to order the standards. MolaKule mentions 25 ppm back in 2003, is this what's being used today?

Stinky


I think the best way to see what's being used is to just test the virgin oil and see. Other than that, the only way to know for sure is to get the oil companies to tell you how much they are using, and the chances of that happening are very slim.
 
quote:

Can someone tell me the expected value?

It's going to vary between gear oils, greases, and engine oils.

For engine oils, < = 30 ppm.

For gear lubes and spray greases, expect up to 500 ppm, and usually less than 750 ppm.

Most Antimony will be in the form of Antimony dithiocarbamates or SbDTC.
 
Thanks Mola

G-man, We need to know the approximate range so I can get the correct standards to calibrate the instrument. We normally use 3 standards to establish a calibration curve. For example we will use a blank, a low standard that is slightly below the expected value, and then a high standard that is above the expected value. When we run samples that are between the standards we will get accurate results, but when we venture outside the curve the accuracy decreases.

Just thought you might like to know the reason I was asking.
 
Are there more lubricant known for their antimony content beside the Bio-SynXtra HD Plus SHP 5w40 (Low Ash) from RLI?

Christian
 
Originally Posted By: miami993
Are there more lubricant known for their antimony content beside the Bio-SynXtra HD Plus SHP 5w40 (Low Ash) from RLI?

Christian


I haven't uncovered any as yet.

Schaeffer's 132 (oil additive) has some Sb.


RLI found that with Bio-synthetic oils, their type of Sb is multi-functional and acts as an anti-oxidant, friction reducer, and anti-wear agent.
 
Last edited:
Originally Posted By: miami993
Are there more lubricant known for their antimony content beside the Bio-SynXtra HD Plus SHP 5w40 (Low Ash) from RLI?

Christian


All Schaeffer's oils have about 70ppm in them - think it may be part of their patented Micon Moly, but even if not it is in there. It does not show up on most VOA/UOA on here as most labs do not test for it.
 
Originally Posted By: Jax_RX8
Originally Posted By: miami993
Are there more lubricant known for their antimony content beside the Bio-SynXtra HD Plus SHP 5w40 (Low Ash) from RLI?

Christian


All Schaeffer's oils have about 70ppm in them - think it may be part of their patented Micon Moly, but even if not it is in there. It does not show up on most VOA/UOA on here as most labs do not test for it.


That's true and thanks for reminding us as I had forgotten about Schaeffer's oils.
 
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