| 摘要 |
A protective hardcoating system is provided for a metallic substrate of a downhole tool. The metallic substrate is generally characterized by a thermal coefficient. The hardcoating system includes a hardface coating that is applied onto the substrate to protect it against wear. The hardface coating includes an interface section positioned adjacent to the substrate and defining an interface therewith, and a hard surface section positioned externally of the interface section. Further, the hard surface section includes an exposed surface. In this hardcoating system, the interface section and the surface section have a composition including a predetermined hardness component constituency and a thermal coefficient at least partially attributable to the hardness component constituency. The hardness component constituency of the interface section is distinct from the hardness component constituency of the hard surface section such that the difference between the thermal coefficient of the interface section and the thermal coefficient of the substrate is substantially less than the difference between the thermal coefficient of the substrate and the thermal coefficient of the surface section.
|
