ABSTRACT
This review focuses on several theoretical and technological aspects of waterbased lubricants, primarily their appearance, aging, lubricity, and wetting on metal surfaces. Colloidal properties of major categories of lubricant emulsions are compared, describing the importance of micelles, lamellae, vesicles,
Abstract .................................................................................................................. 149 7.1 Introduction: Colloidal Categories of Water-Based Lubricants ................... 150 7.2 Water-Lubricant Oil-Surfactant (Emulsier) System ................................. 151
7.2.1 Emulsication Mechanism in Colloid Formation............................. 153 7.2.2 Self-Aggregation and Solubilization ................................................. 156 7.2.3 Thermodynamic Considerations of Water-Lubricant
Oil-Surfactant Systems .................................................................... 159 7.3 Importance of Colloidal Processes in Key Properties of Lubricant
Emulsions...................................................................................................... 161 7.3.1 Effects of Colloids on Lubrication at Molecular Level .................... 161 7.3.2 Inuence of Colloidal Transformations on Lubricant
Appearance and Storage ................................................................... 162 7.3.3 Colloidal Processes during Surface Wetting .................................... 165 7.3.4 Key Surfactants for Surface Wetting Control ................................... 167
7.4 Conclusions ................................................................................................... 169 Acknowledgments .................................................................................................. 169 References .............................................................................................................. 170
droplets, and other colloidal structures. Molecular mechanisms are suggested to explain the aging processes of lubricant concentrates and emulsions as well as lubricant lm formation both on the open surface, as in wetting, and between the moving surfaces. Attention is also given to the chemical structures of surfactants, used to control wetting of metal surfaces by water-based lubricants.
