Linear Gradient Ceramic/Metal Whisker-Toughened Ball Bearing

This project develops an innovative and efficient ceramic/metal whisker-toughened bearing with a linear gradient in density. It includes the development of a ceramic metal composite ball/roller bearing magnetic casting process to fabricate a material that will gradually change from pure ceramic at the center to a nearly pure metal on the surface while spreading the thermal/mechanical stresses through the bearing. The bearings interface with conventional materials, maintain a lubricated state and have the high compressive strength of the ceramic. The linear gradient ceramic/metal whisker-toughened ball bearing has compressive strengths in excess of ball bearing steels, is erosion resistant at high temperatures, is resistant to chemicals, can withstand mechanical and thermal cycling, is heat and friction-resistant, can support large axial and radial loads and requires little lubrication. Slip casting subjected to vibration and magnetic fields will produce a linear distribution of the ceramic matrix. The ceramic composite ball bearing will reduce life cycle costs by extending bearing life, eliminating spares and reducing inventories. Theoretical development, solid/fluid modeling and experiments will demonstrate the feasibility of the approach. This new design can be manufactured at equivalent costs to materials currently used by the military and can be retrofitted to existing systems.