Nano-crystalline Diamond Coated Carbide Ball Description (2/2)

Generally, solid lubricant can be specifically divided into 3 types, solid powder lubricant, solid lubricant film and self lubricating composite material. Today has been successfully put into production solid lubricant film are tungsten diselenide (WSe2), boron nitride (BN), molybdenum disulfide (MoS2), gold (Au), silver (Ag), lead (Pb), etc. While nano-crystalline diamond films belong to one solid lubricant film, it has a high hardness, low friction coefficient, good chemical stability, high thermal conductivity and high modulus of elasticity so that it has a broad application prospect. Nano-crystalline diamond films are typical “cauliflower” structure with average grain size of 10-20 nm and homogeneous thickness around a sphere. The surface roughness increases with growing of film thickness. Mechanical properties of nano-crystalline diamond films were also tested by nano-indentation. The hardness and elastic modulus are about 40 GPa and 50 GPa, respectively.

In addition, Nano-crystalline diamond solid lubricant film can be applied to a number of pharmaceutical machinery, ball bearings, ball bearings present these are mostly silicon nitride (SiN) ceramic materials, etc., which would make the cost high the lack of elastic modulus and wear resistance and other properties. If we directly choose tungsten carbide ball with lower price, it can decrease the production cost, but the composition containing tungsten carbide ball of W, Co cobalt and other heavy metals, the event will wear the metals penetrate contaminated drugs, endangering patients and health. Therefore, solid nano-crystalline diamond films on the one hand to enhance the hardness of ball bearings, wear resistance and service life, a small part of the toner layer on the other hand nano-crystalline diamond worn infiltrated harmful to human health is extremely small, almost negligible.