Lubricant Additives

Ashless Antiwear and Extreme-Pressure Additives 235

PRO

OR′

O

H

R′′-CH=O

PRO

OR′

O

CHR′′ OH

P 2 O 5

Amines

PRO

OR′

O

CHR′′ O P(O)(O) 2 (H 3 N R′′′) 2

O

O

P(O)-O H 3 N R′′′

POR

OR′

O

CHR′′

PRO

OR′

O

CHR′′

+

(8.38)

The synergistic antiwear performance of the aforementioned complex phosphorus additives
are illustrated in Chart 8.1. Nine different analogues were synthesized and tested at 1 wt% in base
oils using three different conditions in the Four-Ball Wear test. As demonstrated, they all exhibit
exceptionally good antiwear properties.

8.2.8 HALOGEN ADDITIVES

Chlorine was one of the earliest antiwear and EP elements used in the lubricant industry.
Chlorine-containing additives are still used in cutting oils and related metalworking lubricants, in
combination with sulfur additives. Iodine was mentioned in aluminum-processing lubricants for
wea r control. Fluor ine, in perfl uor inated compounds, is well k nown to reduce wea r and especially
friction.

WSD

0

0.5

1

1.5

2

2.5

BS BS +

1% (A)

BS +

1% (B)

BS +

1% (C)

BS +

1% (D)

BS +

1% (E)

BS +

1% (F)

BS +

1% (G)

BS +

1% (H)

BS +

1% (I)

Four-Ball Wear Test (WSD in millimeters)

Test 1−93C, 40 kg, 1800 rpm, 30 min

Test 2−93C, 60 kg, 1500 rpm, 30 min

Test 3−135C, 60 kg, 100 rpm, 30 min

All tested additives (A−J) were derived from dibutyl phosphite, butyraldehyde, and a selected amine at various molar ratios.

A and B: using Primene JMT at different ratios, C and D: using Adogen 183 at different ratios, E,G, and I: using Duomeen

O at different ratios, F and H: using bis 2-EH amine at different ratios.

CHART 8.1 Complex phosphorus additives. (BS, base stock; WSD, wear scar diameter.)