Originally Posted By: MolaKule
I would like to see some data on those last two items on the Dichlorobenzenes. An Iron chloride is a salt. Why would it be beneficial if it "interferes" between an AW additive/anti-oxidant such as ZDDP and the surface it is supposed to protect?
Mola - here is the primary source I was able to find during my research on the effects of Dichlorobenzenes aiding lubricity and providing AW/EP properties.
As I understand it, dichlorobenzenes are one type of chlorinated hydrocarbons, and as such the research I found below on Extreme Pressure tribology of Chlorinated Hydrocarbons applies (although they use different chlorinated hydrocarbons for the research).
The first sentence is:
"Chlorinated hydrocarbons are commonly added to a base lubricating fluid when it is used for extreme-pressure (EP) lubrication of ferrous metals. It is demonstrated here that the interfacial temperature in the EP regime varies linearly with the applied load in a pin and v-block testing apparatus and that temperatures in excess of 11000 K can be attained. Thermally decomposing chlorinated hydrocarbon vapors on iron heated to these temperatures (1) shows that a film consisting of an iron chloride which incorporates small carbon particles (~50Angstrom) is formed. In this paper, tribological measurements at extreme pressures and the corresponding analyses of the rubbing surfaces and wear particles also indicate that this film, formed from the chlorinated lubricant reacting with these surfaces, is the critical antiseizure material at less severe EP loads and interfacial temperatures less than ~1000 K"
Following are two links of a research paper I found:
Part 1
Part 2
There is a significant amount of detail and analysis (with the pictures missing), but here are the conclusions from both Parts:
Part 1
"Type I" tribological behavior for relatively low concentrations of chlorinated hydrocarbons added to PAO apparently results from reactive film formation with iron. Surface analyses indicate that the film consists of FeC1^sub 2^ and carbon. This film prevents seizure between rubbing steel surfaces until its temperature approaches the melting point of ferrous chloride in the pin and v-block rubbing interface. At the melting temperature, its shear strength apparently drops quickly and the film is removed much more rapidly than it can be formed by further reaction. Part II examines the kinetics of film formation and the quantitative aspects of its removal, thereby allowing the modeling of this interface."
Part 2
"Ferrous chloride and apparently carbon from chlorinated hydrocarbon additives both play important and varied roles under EP lubricating conditions. It may be rationalized that carbon's availability and movement within the sliding surface reaction layer affects seizure load, (mu) and wear rates and the transition from Type I to Type II behavior."
