Innovators at NASA's Glenn Research Center have developed a method for fabricating a fiber-reinforced diamond composite coating on the surfaces of sliding thrust bearings at low and cryogenic temperatures. The innovative composite coating is a mixture of diamond particles, organic chemicals, and fibers or fabrics. The diamond particles provide high hardness, and the fibers and binding matrix provide high-fracture toughness. Glenn's fabrication method can be tailored to meet a range of performance requirements for lightweight, low-temperature sliding thrust bearing applications. For example, the volume fraction of diamond particles can be increased to enhance the hardness of the composite coating, or the volume fraction of binding matrix can be increased to enhance its crack or fracture resistance. Glenn's method offers a diamond composite coating that is more cost-effective, wear-resistant, and fracture-tough than existing alternatives.
The technology utilizes existing materials and commercially available equipment, and reduces the time and cost needed for production. Diamond particles are mixed with components of epoxy glue or other polymeric (olygomeric) materials. Fibers and mixture are placed onto metallic, ceramic, polymeric, or composite substrate and compressed under a pressure of less than 100 MPa at room temperature. Heat treatment is then done at ambient pressure and a temperature of less than 200 °C to yield the composite coating or solid parts.
This technology can be used for protective coatings, sliding bearings wear parts, and high-strength tools.