Introduction to lubricant additives in short

1. Submitted By Submitted To
Shivanshu Trivedi Dr. R. K. Mondloi
Scholar No. 162116219 Coordinator
M. Tech. I Sem. Maintenance Engg.
Maintenance Engg.

2. Introduction
 Lubricants are not just oils they contains chemical compounds
as well.
 Lubricants comprises of base oil and additives.

3.  Additives are chemical compounds that improve
the lubricant performance of base oil (or oil “base stock")
 Additives are organic or inorganic compounds dissolved or
suspended as solids in oil.
 Additives typically range between 0.1 to 30 percent of the
oil volume, depending on the application of lubricant.
 The additives are used to enhance the performance
characteristics of the lubicating oil.
 Additives suppresses undesirable properties and impart
new required properties in base oil

4. Why we need additives in lubricants?
 In Gears at very high contact stresses lubricant will be
squeezed out, metal to metal contact occur so to avoid failure
and seizure of parts we require extreme pressure additives.
 In IC Engines there is a very high working temperature, at this
temp. lubricant may oxidize that effects in reducing efficiency
and damaging engine so to avoid oxidation additives are used.
 Refrigerating systems operate at very low temp lubricating oil
required a flow ability to get circulated from one place to
other place so that it can carry wear debby particle, requiring
low temperature lubricant, need to add additives to impart low
temperature properties .
 From above examples it is clear that additives are needed in
lubricating oils as they improve the characteristics of base
stock as required.

5. Role of Additives
Additives have three basic roles:
 1) Enhance existing base oil properties with antioxidants,
corrosion inhibitors, anti-foam agents and demulsifying
agents.
 2) Suppress undesirable base oil properties with pour-point
depressants and viscosity index (VI) improvers.
 3) Impart new properties to base oils with extreme pressure
(EP) additives, detergents, metal deactivators and tackiness
agents.

6. Types of lubricant additives
 Performance Enhancing Additives - Improves overall properties
of lubricants
 Viscosity Index improvers
 Anti foaming additives
 Detergent or Dispersant additive
 Pour point depressant
 Acid neutralizer additives
 Surface protecting additives – protects the interacting surfaces
in metal to metal contact from chemically active lubricants.
 Extreme pressure additives
 Anti rust additives
 Antiwear additives
 Lubricant protecting additives – protects the lubricity of base oil
 Anti oxidant additives
 Emulsifier additives

7.  Detergent additives, dating back to the early 1930s, are used
to clean and neutralize oil impurities which would normally
cause deposits (oil sludge) on vital engine parts. Typical
detergents are magnesium sulfonates.
 Corrosion or rust inhibiting additives retard the oxidation of
metal inside an engine.
 Antioxidant additives retard the degradation of the stock oil
by oxidation. Typical additives are
organic amines and phenols.
 Metal deactivators create a film on metal surfaces to prevent
the metal from causing the oil to be oxidized.
 Pour point depressants improve the oil's ability to flow at
lower temperatures

8.  Viscosity modifiers make an oil's viscosity higher at elevated
temperatures, improving its viscosity index (VI). This
combats the tendency of the oil to become thin at high
temperature. The advantage of using less viscous oil with a VI
improver is that it will have improved low temperature
fluidity as well as being viscous enough to lubricate
at operating temperature. Viscosity modifiers are often plastic
polymers.
 Friction reducers, like molybdenum disulfide, are used for
increasing fuel economy by reducing friction between moving
parts. Friction modifiers alter the lubricity of the base
oil. Whale oil was used historically.
 Extreme pressure agents bond to metal surfaces, keeping
them from touching even at high pressure.
 Antiwear additives or wear inhibiting additives cause a film
to surround metal parts, helping to keep them separated. Zinc
dialkyldithiophosphate or zinc dithiophosphates are typically
used.

9.  Dispersants keep contaminants (e.g. soot) suspended in
the oil to prevent them from coagulating.
 Anti-foam agents (defoamants) inhibit the production
of air bubbles and foam in the oil which can cause a
loss of lubrication, pitting, and corrosion where
entrained air and combustion gases contact metal
surfaces.
 Antimisting agents prevent the atomization of the oil.
Typical antimisting agents are silicones.
 Wax crystal modifiers are dewaxing aids that improve
the ability of oil filters to separate wax from oil. This
type of additive has applications in the refining and
transport of oil, but not for lubricant formulation.
 Rust inhibitor prevent rust formation by forming a
protective surface film

10. Usage of common additives

11. How Additives Work
 Additives are polar molecules or elements.
 Additive polarity is defined as the natural directional
attraction of additive molecules to other polar materials
in contact with oil.
 It’s important to note that additives are also sacrificial.
Once they are gone, they’re gone.
 Additives are attracted to, such as dirt, silica and water,
the additives will cling to the contaminants and settle to
the bottom or will be filtered out.
 There are a three polar mechanisms such as particle
enveloping, water emulsifying and metal wetting occurs
generally in additives.

12.  Particle enveloping means that the additive will cling to
the particle surface and envelop it. These additives are
metal deactivators, detergents and dispersants. They are
used to peptize (disperse) soot particles for the purpose
of preventing agglomeration, settling and deposits,
especially at low to moderate temperatures.
 Water emulsifying occurs when the additive polar head
clings to a micro-droplet of moisture. These types of
additives are emulsifying agents.
 Metal wetting is when additives anchor to metal
surfaces, which is what they are supposed to do. They
attach to the interior of the gear casing, gear teeth,
bearings, shafts, etc. Additives that perform this
function are rust inhibitors, anti-wear (AW) and EP
additives, oiliness agents and corrosion inhibitors.

13. Too much of a good thing
 When using oil additives, more is not always better. As more
additive is blended into the oil, sometimes there isn’t any
more benefit gained, and at times the performance actually
deteriorates. In other cases, the performance of the additive
doesn’t improve, but the duration of service does improve.
 In addition, increasing the percentage of a certain additive
may improve one property of an oil while at the same time
degrade another. When the specified concentrations of
additives become unbalanced, overall oil quality can also be
affected.
 Some additives compete with each other for the same space
on a metal surface. If a high concentration of an anti-wear
agent is added to the oil, the corrosion inhibitor may become
less effective. The result may be an increase in corrosion-
related problems.

14. Trends in Lubricant Additives
 Need for enhanced lubricant performance is overreaching
mega trend in automotive, marine, aviation, and industrial
segments. Base oils are complemented with additive
packages to enhance lubrication and reduce toxic
emissions.
 Reducing consumption of expensive and non renewable
petroleum based lubricants.
 Industries and Governments are in a continual search for
high performance lubricants that does not affect
environment and reduce carbon footprint.

15. References
 www.Wikipedia.org
 NPTEL Videos
 Hand book of Maintenance Engg. By McGraw Hill
 www.machinerylubrication.com
 www.elf.com
 Chevron Oronite's oil Additives

16. Thank You