Tribological Behavior of Ashless Antiwear Compounds

1
Tribological Behavior of Ashless Antiwear
Compounds

• BoHoon Kim
• Ph.D. Candidate, Materials Science and
  Engineering
• The University of Texas at Arlington
• nanbohoon_at_hotmail.com

2
Outline

• Introduction
• Materials Six Antiwear Additives
• Result
• - Wear Properties Tribological Test
• - Wear Surface SEM/EDX
• - Wear Debris (5000 cycles) TEM
• Conclusion

3
Objectives

• to understand Boundary Lubrication Mechanism of
  Ashless Additives
• to analyze Characteristics
• - Tribo-Film, Antiwear Chemistry
• to develop New Antiwear Agents
• - Low Phosphorous, Better Antiwear
  Performance, Metal-Free

4
Introduction

• Definition of Ash the solid residue left when
  combustible material is thoroughly burned or is
  oxidized by chemical means
• (Merriam-Webster
  Online Dictionary )
• Ashless NO METAL (Zn FREE)

5
Introduction

• Advantage of ZDDP
• - Outstanding Anti-Wear and Anti-Oxidant
  Properties
• - Economical Anti-Wear Additive
• Disadvantage of ZDDP
• - Toxicity, Waste Disposal, Filter Clogging,
  Pollution, and Deposition on Catalytic
  Converter
• - Hydrolysis Clogging and Depositing

6
Materials
Coded Name Trade Name Chemical Name Structure Density at 20C Flash Point P S Decomposition Temp. Range Temp. for 50 weight Loss
AD Irgalube 63 Ashless Dithiophosphate 1.1g/cm3 114C 9.7 21.5 80C- 250C 180C
MAP Irgalube 349 Mixture of Amine Phosphate 0.92g/cm3 135C 4.8 - 125C-260C 240C
DDD Irgalube 353 Dialkyl Dithiophophate Derivative 1.11g/cm3 162C 9.3 19.8 125C-240C 210C
TP 1 Irgalube 211 Alkylated Triphenyl Phosphorothionate 1.0g/cm3 108C 4.3 4.4 225C-400C 325C
TP 2 Irgalube 232 Butylated Triphenyl Phosphorothionate 1.18g/cm3 162C 7.9 8.1 180C-320C 290C
TP 3 Irgalube TPPT Triphenyl Phosphorothionate 1.19g/cm3 gt200C 8.9 9.3 125C-350C 250C
7
TRIBOLOGICAL TESTThe BallOnCylinder Lubricity
Evaluator (BOCLE)
(a) The ball on cylinder lubricity evaluator
(BOCLE) developed at UTA (b) Schematic three
dimensional PRO-E drawing of the homebuilt BOCLE

1. The loading setup in the BOCLE
2. Friction force measurement

8
Analysis of Wear Properties
All tests for the Ashless Dithiophosphate (AD)
failed.
9
Analysis of Wear Properties
10
Analysis of Wear Properties
measured at failed point
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Analysis of Wear Properties

• Dialkyl Dithiophosphate Derivative(DDD)
• - Excellent Antiwear Agent
• Primary Compound is more Stable than Secondary
  Compound.
• - Ashless Dithiophosphate(AD)
• Poor Perfomance
• - Dialkyl Dithiophosphate Derivative(DDD)
• Good Performance
• Thermal Stability is Important for Wear
  Protection.
• - Triphenyl Group Case

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Analysis of Wear Track
a) Ashless Dithiophosphate ( measured at
failed point)
c) Dialkyl Dithiophosphate Derivative
b) Mixture of Amine Phosphate
d) Alkylated Triphenyl Phosphorothionate
e) Butylated Triphenyl Phosphorothionate
f) Triphenyl Phosphorothionate
13
Analysis of Wear Track
14
Analysis of Wear Track
Phosphorous Mapping of Dialkyl DithioPhosphate
Derivative(DDD)
15
Analysis of Wear Track

• Width of Dialkyl Dithiophosphate Derivative(DDD)
  is the Narrowest.
• - Good Wear Protection
• Stable and Protective Tribofilm (Dialkyl
  Dithiophosphate Derivative(DDD))
• - Formation of Phosphates
• - Amorphous Films that contain Fe-O-P

16
Analysis of Wear Debris
Low Magnification
High Magnification
b) Mixture of Amine Phosphate
c) Dialkyl Dithiophosphate
Derivative
a) Ashless Dithiophosphate
17
Analysis of Wear Debris
Low Magnification
High Magnification
f) Triphenyl Phosphorothionate
d) Alkylated Triphenyl Phosphorothionate
e) Butylated Triphenyl Phosphorothionate
18
Analysis of Wear Debris

• Dialkyl Dithiophosphate Derivative(DDD) has the
  largest and well defined Amorphous Film. Low
  Magnification
• Chemistry with Many Small Fe2O3 Particles has
  poor wear performance.
• - High Magnification
• - Fe2O3 Abrasive Material

19
Conclusion

• Dialkyl Dithiophosphate Derivative(DDD) is an
  Excellent Antiwear alternative to ZDDP.
• Decomposition of the antiwear additive is a
  primary prerequisite for the formation of stable
  tribofilm.
• - Ashless Dithiophosphate(AD) is more stable
  than Dialkyl Dithiophosphate Derivative(DDD) .
• Three triphenyl compounds generally performed
  poorer than the Dialkyl Dithiophosphate
  Derivative (DDD).
• - Thermal Stability

20
QUESTION