New material concepts for thermally sprayed hydrodynamic bearings

Hydrodynamic bearings have to fulfill different requirements, depending on the operating conditions. Yet, conventional hydrodynamic bearings could not be used in critical operating conditions such as permanent start / stop operations. This is the reason why rolling bearings are currently used for frequent starting operations and low circumferential velocities. In order to operate hydrodynamic bearings in a fail-safe manner even under these increased requirements, new bearing materials are needed.

In this study two new bearing material concepts are developed and deposited by thermal spraying as coatings to interact in this tribological system. On the one hand, matrix materials containing friction-reducing solid lubricants and on the other hand, multilayer systems, which can be used in as-sprayed condition, are investigated. The aim of both concepts is to improve the operation properties under emergency conditions. The coating concepts are therefore tested on a modified highload ring-on-disc tribometer and are compared to a reference plain bearing material produced by conventional casting. Depending on the materials chosen to realize the above mentioned concepts, lower wear rates and friction coefficients can be achieved compared to conventionally used bearing materials.