International Conference on Engineering Education and Research "Progress Through Partnership" © 2004 VSB-TUO, Ostrava, ISSN 1562-3580 609 A Collaborative Program for Development of Frictional Materials Using Industrial Wastes Yoginder P. CHUGH, Peter FILIP, Samrat MOHANTY & Kok-Wai HEE Center for Advanced Friction Studies, College of Engineering, Southern Illinois University, Carbondale, Illinois 62901, USA ABSTRACT: Current frictional materials, for example automotive brakes, consist of ingredients (abrasive powders, steel or copper chips, binders etc.) with very diverse physical, engineering and thermal properties. The authors believe that several of the problems associated with such frictional materials (low contact area, noise, vibration, temperature development and dissipation) can be overcome if ingredients have smaller diversity in their properties. Furthermore, the production cost of such materials can also be reduced through large volume use of industrial wastes readily available in most countries in the world. Working in cooperation with industrial partners, the authors have made considerable progress toward development and characterization of such materials over the last 4-months. Additional studies are continuing to optimize composition of such frictional materials and develop commercially viable brake pads. Industrial partners will test these materials and modify them, in cooperation with authors, to implement their production and marketing. The collaborative program involves faculty and students with diverse backgrounds and student training is an integral part of the program. 1 INTRODUCTION 1.1 Background and need for research in friction materials Surface interactions between two touching solids are of universal importance since solids represent a substantial portion of our world. Here, we are concerned with the friction effects of surface interactions, which represent ability of touching solids to transfer tangential force at different applied normal loads. Associated effects of interest include wear and adhesion phenomena. Wear represents removal of material from the surfaces of one or both of the contacting bodies. Adhesion implies the ability of contacting solids to withstand tensile forces upon application of normal compressive forces. A well known topical area where friction, wear, and adhesion play major roles is in the use of friction materials for braking effort to control the speed of moving bodies; e.g. automobiles, trains, etc. The term “tribology” refers to the knowledge base concerned with the mechanical surface interaction phenomena in solids. The processes of friction, wear, and adhesion are complex and involve properties of both contacting solids. The ability of the current knowledge base to predict these behaviors from the more fundamental engineering properties is limited and more research is needed in the area. It is however well established that these properties involve volume or bulk properties of the solids as well as the more intuitive contacting interface of these bodies or surface properties. Examples of bulk engineering properties include plasticity and yield behavior and their temperature dependence, elastic properties including ability to store elastic strain energy, and the more obvious thermal properties, including conductivity and diffusivity properties. Surface properties of importance include ability to develop a surface film with properties different than those of the substrate, ability to absorb molecules from the environment, and surface energy of the bodies in contact. It is important to note that atomic bonds play a critical role in a solid and the friction and wear properties are related to these bonds in a rather complex manner not well defined by research to date. A few metals and alloys will form very thin film in (≈10 -5mm) air while developing very different films of nitrides, sulfides, and chlorides in other environments. These films and their characteristics play an important role in surface interactions. In addition to the surface film, metals and non-metals alike develop an adsorbed film, which primarily consists of molecules of water vapor and oxygen and has thickness of about 3x10-7 mm. This adsorbed film can reduce surface interaction properties. Surface energy of the solids also plays a role in friction and wear properties but its role is not fully understood.