Wear Life with Sliding Speed

Sliding speed (m/s) Wear life (mins) Wear life (m) 

Test conditions burnished film, conformal contact,  

There are probably four important modes of failure of molybdenum disulphide films, namely loss of adhesion or film break-up), wear, oxidation, and possibly fatigue. 

One form of film break-up has been mentioned previously, in which the surface of a relatively thick film becomes consolidated over a soft unconsolidated layer. This can lead to shear in the soft layer, especially with high non-conformal loading, and the consolidated layer will break away. Loss of adhesion and film break-up can also occur, especially with a bonded film, if the surface pre-treatment has been badly performed, so that the coating simply fails to adhere and breaks away. These cases may be considered as premature failures caused by poor film preparation. 

Where a film has been well prepared and burnished to a high degree of consolidation and reflectivity, and is run against a similar film on the counterface, sliding will take place almost entirely between the smooth surfaces. Under those circumstances the wear rate will be extremely low, and may for a period even be nil, so that the mean film thickness remains unchanged for the remainder of the film 

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Table 7.1 Variation of Wear Life with Sliding Speed (Ref. 132)...

Several authors have reported a decrease in wear life with increasing sliding speed . Table 7.1 shows the results obtained by Kinner, and Figure 7.13 those of Bartz . Such results can be misleading because it would be normal for the life in minutes to be reduced in proportion to the increase in speed. Conversion of Kinner s figures to show life in sliding distance shows that in fact there was little... 

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