Interface Micro-nano Carbon Materials Dependence On The Tribological Properties Of Polycrystalline Diamond

Polycrystalline diamond is a widely used super-hard drilling material,with its low friction coefficient,wear resistance,ultra-high hardness and other excellent performance.It has broad application prospects in the field of tools and other fields.In practical engineering applications,polycrystalline diamond tools are worked in a variety of harsh working conditions,which will inevitably produce severe friction and wear,reduce their working efficiency,and even lead to workpiece failure in severe cases.According to literature research,humidity,atmosphere and vacuum environment factors have a greater impact on the friction and wear of polycrystalline diamond.In this paper,by controlling the different interface conditions of polycrystalline diamond materials(micro/nano carbon materials,humidity,alternating atmosphere,vacuum),and the friction and wear mechanism of polycrystalline diamond and silicon nitride materials are explored.Research results show:(1)On different micro/nano carbon materials and relative humidity composite conditions,the polycrystalline diamond has little difference in friction coefficient between the micro/nano carbon material and the blank control group when the silicon nitride balls are in 5% and 40% relative humidity.The coefficients are stable at about 0.05 and 0.11 respectively;The friction coefficient after adding onion-like carbon between the interfaces in 10% to 30% relative humidity is about 0.043,0.058 and 0.085.After adding onion carbon between the interfaces,a large amount of carbon source is provided for the grinding pair,and a thick carbon transfer film is formed at the grinding interface,and the onion carbon particles also act as rolling nano-bearings between the interfaces,thus resulting in the lowest coefficient of friction.(2)On different micro/nano carbon materials and relative humidity composite conditions,the polycrystalline diamond has little difference in friction coefficient between the micro/nano carbon material and the blank control group when the silicon nitride balls are in 5% and 40% relative humidity.(3)Onion-like carbon has the advantage of reducing friction and wear rates in both air and vacuum.The addition of onion-like carbon between the friction interfaces in a vacuum atmosphere facilitates the formation of a carbonaceous transfer film during the rubbing process.The friction coefficient fluctuated from 0.2 to 0.5 when no onion-like carbon was added under a 2N load;the friction coefficient after the addition of onion-like carbon was reduced to about 0.03,and the wear was also greatly reduced.The carbonaceous transfer film formed by friction under vacuum can only withstand lower loads.The transfer film formed by the addition of onion-like carbon to the 2N load can maintain a friction coefficient as low as 30 minutes for up to 30 minutes,while the addition of onion-like carbon at a higher load of 10 N can only maintain a lower friction coefficient of about 0.05 for about 4 minutes,followed by friction.The coefficient has risen sharply.can be maintained at a higher load of 10 N,and then the friction coefficient rises sharply.