Surface layer for the working surface of the cylinders of a combustion engine and process of applying the surface layer
US6701882B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Feb 14, 2003 |
| Grant date | Mar 9, 2004 |
| Priority date | — |
| Expiry date | Feb 14, 2023 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC23C4/16
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A surface coating of the working surface of a cylinder of a combustion engine is disclosed, having the combination of the following characteristics:The coating is applied by plasma spraying; the surface of the coating comprises a plurality of open pores; the degree of porosity of the surface of the coating amounst to between 0.5 and 10%; the statistic mean pore size amounts to between 1 and 50 &mgr;m, whereby at least nearly exclusively pores with a size of less than 100 &mgr;m are present; the pores are stochastically distributed in the surface of the coating, both as far as the area and the size is concerned; the coating comprises a content of bound oxygen of between 0.5 and 8% by weight; the coating comprises inclusions of FeO and Fe3O4 crystals, serving as solid lubricants; and the roughness of the surface of the coating is adjusted by mechanically finishing to an arithmetic mean roughness Ra of between 0.02 and 0.4 &mgr;m and to a mean peak-to-valley distance Rz of between 0.5 and 5 &mgr;m. The pores form a plurality of micro chambers, supporting the build-up of an oil film between piston rings and cylinder wall.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.