Nickel Wear Data

Adhesive Wear Performance

Adhesive Wear Tests - Results
Pin on Disc Test - ASTM G99
The results of this series of tests are expressed in terms of wear rate and wear coefficient. An assessment of the amount of surface oxidation is also given and directly related to the performance of each material. The results underline the positive effects of a stable oxidative wear condition. The chemistry of the resultant oxide film on the surface of the wear specimens is also given in order to underline the importance of oxide species in relation to oxide film stability.

The percentage surface oxidation is also give* - Assessment make from SEM normal and back scatter images

** Oxide elements are given in order of predominance
*An oxidative wear mechanism was observed throughout these tests.
++ This test resulted in the failure of the specimen during the test.

In addition to assessing the positive effects of an oxide film, the test results are also compiled to illustrate the lack of correlation between the matrix hardness of the materials and wear results. The coefficient of friction (µ) is also given for the stable running conditions of the test. This helps to illustrate that stable oxidative wear conditions generally result in a lowering of µ in the stable running conditions.

The results also illustrate a lack of relationship in wear performance related to the macro hardness of the test material. Whilst the macro hardness of the specimens was generally above 600Kg/mm2 the variations in hardness has not influenced the results. This underpins field experience where wear performance is influenced by the high temperature properties of the material within the wear couple.

Abrasive Wear
A series of abrasive wear tests have been conducted and, to some extent, are on going in order to rank the performance of Sagittite¨ in relation to other materials traditional used for similar applications. Clearly this information can only be used to rank performance of the relative materials due to the significant environmental differences between test methods and in field applications. The problems associated with predicting performance in new and potential applications is a longstanding difficulty. As a result the assessment/prediction of potential performance is therefore largely based upon a combination of ranking tests and historical field experience.

A set of results, based around the ASTM G65 abrasive wear test, are given here as a guide but the environment associated with individual application must be taken into account before material choices are made. It would be standard practice to assess each application to identify, as near as possible, the actual material degradation mechanism. This can be complex and may cover a number of mechanisms operating as a combined event; for example Ð corrosion erosion, erosion, adhesive and abrasive (two body and three body wear) and the potential effects of elevated temperature.