Preface

Chapter 7 **Lubrication and Friction of Porous Oil Bearing Materials 113**

Yanguo Yin and Guotao Zhang

**VI** Contents

Lubrication is critical in any application where moving parts are involved. As problems faced by the world increase in complexity, lubrication increases in importance while the conditions while lubrication is required under more extreme conditions of speed, tempera‐ ture, and stress. In addition, the materials to be lubricated have become more exotic and potentially reactive due to the increased stress and temperature requirements. In the near future, lubricants with different compositions will be necessary for various applications, in‐ cluding refrigeration due to the development of more environment-friendly refrigerants and aerospace due to the use of higher-performance alloys for bearings and machining to reduce hazardous waste generation, among others. The extreme conditions make the properties of both the lubricant base stock and the additives more important and have required the devel‐ opment of more exotic bearing materials, including composition, surface treatments, and processing techniques.

This book is divided into two sections: first, the chemistry of some lubricants and lubricant additives are examined. Typical lubricant base stocks do not have ideal lubricating properties for use in many applications, so a series of additives are formulated to improve these proper‐ ties. The chapters include both experimental and theoretical approaches to the decomposition of the lubricants and additives. Second, the lubrication of a variety of different substances is investigated in order to optimize lubricant properties for certain applications. It has become more apparent that the environmental effects and human health effects of degraded lubri‐ cants and additives are also important. Some of these studies are directed toward the develop‐ ment of more environment-friendly materials and lubricants for important applications. This book covers some of the important research in the area of lubricants and lubrication.

> **David W. Johnson** University of Dayton Dayton, Ohio, USA

**Section 1**

**Lubricant and Additive Reactivity**

**Lubricant and Additive Reactivity**

**Chapter 1**

**Provisional chapter**

**Ab-Initio Modeling of Lubricant Reactions with a Metal**

In this chapter, to assist the design of aluminum processing, density functional theory is utilized to depict optimal adsorption geometries on an Al (111) surface for two commonly used boundary-layer lubricant additives: vinyl-phosphonic and acetic acids, i.e., tri-bridged, bi-bridged, and uni-dentate coordinations of these adsorbates are examined to determine the optimal binding sites on the surface. During these static analyses, charge density of states for molecular oxygen ions reacting with Al ions in the surface is applied to revealing the evolution essentials of molecular binding strength on surface. In addition, ab-initio molecular dynamics based upon density functional theory is employed to probe dynamic decomposition pathways on the Al (111) surface for two other important boundary-layer lubricant additives: butanoic acid and butanol alcohol. These decomposition pathways may occur upon molecular collisions with the surface, leading to formation of molecular pieces adhering on surface. Simulations are found to be in qualitative

**Keywords:** density functional theory, ab-initio molecular dynamics, vinyl-phosphonic

Lubricant formulations used to control friction and wear in metallic forming processes typically contain mixtures of molecular additives in the base oil. Common lubricant additives in the metal-rolling processes consist of one or more aliphatic alcohols, acids or esters such as vinyl-phosphonic acid, acetic acid, butanoic acid and butanol alcohol etc. which have hydroxyl (OH) or carboxyl (O═C─OH) functional group [named oxygen-rich base (O-base)] to behave like a cationic anchor with electron-rich charges [1–3]. Initially, these molecules are

**Ab-Initio Modeling of Lubricant Reactions with a Metal**

DOI: 10.5772/intechopen.72512

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution,

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is properly cited.

and reproduction in any medium, provided the original work is properly cited.

**Al (111) Surface**

**Abstract**

**1. Introduction**

**Al (111) Surface**

Additional information is available at the end of the chapter

accord with existing experimental observations.

acid, acetic acid, butanoic acid, butanol alcohol, Al (111) surface

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.72512

Jun Zhong

Jun Zhong

**Provisional chapter**
