Tribochemische Glättung mit Silizium‐Nanopartikeln

Additional silica (silicon dioxide) nanoparticles were added in the tribo‐gap to prevent the severe abrasive wear. The method was a flat surface‐contact reciprocating sliding test between the sintered silicon carbide surfaces with water lubrication. Before testing, the silica nanoparticles were added in the tribo‐gap. These silica nanoparticles acted as a buffer layer during the initial running‐in, thus the abrasion risk was decreased. After running‐in, the silicon carbide surface was tribo‐chemically smoothened without severe abrasion. Comparing to the same tests without silica nanoparticles, the same ultra‐low friction state (friction coefficient was approx. 0.01) was built, and the running‐in period was shortened by 80 %. As has been well reported, the tribo‐chemical smoothening process for silicon carbide needs abundant water, e. g., in the point‐contact tests. However, in the surface‐contact case, water is locally insufficient, which induces severe wear. The preset silica nanoparticles can solve this wear problem. Therefore, it is not necessary to polish the silicon carbide surfaces as the seal faces in mechanical seals. Instead, a pair of rough silicon carbide surfaces can be pressed onto each other and then proceed to a running‐in with preset silica nanoparticles. After running‐in, a pair of precisely mated tribo‐chemically smoothened surfaces can be naturally obtained.