SLIDING COMPOSITE MATERIAL INCLUDING GLASSY CARBONAS A SOLID LUBRICANT

The article presents the basics of producing a sliding composite based on a hypoeutectic aluminum alloyreinforced with glassy carbon foam designed for oil-free contacts of machines and devices. The foam with anopen porosity of 90% was infiltrated with liquid silumin. The tribological properties of the matrix material andthe produced composite were tested in cooperation with GJL-250 gray cast iron on a pin-on-disc tester. A castiron pin with a diameter of 5 mm slid on discs with a diameter of 45 mm at a velocity of 0.5 m/s and a pressureof 0.25 MPa. Tests were performed in technically dry friction conditions and with limited lubrication by asingle application of 2 mg of oil to the friction zone. As a result of the research, it was found that the presenceof 10% of glassy carbon enables the sliding of cast iron against AlSi9NiCuMg silumin under technically dryfriction conditions, reducing its wear by 15% and the friction coefficient by 20% at the beginning and by 18%at the end of sliding. With limited lubrication, composite disc wear is nine times lower than in the case of asilumin disc and pin wear is almost immeasurable. This confirms the effectiveness of glassy carbon as a solidlubricant.