Low-speed sliding tests with nodular cast iron in contact with steel wire and a diamond tip

Scratch testing has been well applied towards the adhesion and failure testing of thin, hard ceramic coatings upon numerous different types of substrate materials. It is common that the test sample is scratched with a contact tip that will not easily deform, such as a Rockwell C diamond tip. Such tips are often not relevant to real, industrial cases, in which the materials of the two counter surfaces are both subjected to some degree of wear. The present paper describes the use of a scratch tester with a newly developed steel wire sample geometry replacing the conventional diamond tip, and the results of the effect of increasing load, loading rate and lubrication may have upon an industrially relevant nodular cast iron versus steel wire contact scenario.

► Friction and wear is markedly different for diamond and steel wire slider tips.
► Critical failure loads for nodular cast iron found to be reliable when using a diamond tip.
► Use of steel wire slider gives realism to scratch and gives relevant friction and wear data.
► Lubrication greatly reduces sliding friction, however it should be optimised.