In tribology everything is possible,

However I think you should give more details about the conditions of  test you have perfomed.

Dear Mr. Kabir, 

The reproducibility of wear tests for thin films/coatings is generally very less. Moreover, the equipment parameters play an important role too. Therefore, it should not be expected that your results should match the results of others. In case you  see a different wear mechansim than others, then it is possible to discuss the differences. 

What type of wear test you have performed? A pin-on-disk test(wear track = circle) or a linear reciprocating test  (wear trac = line) or a ball crater test (wear track = spherical crater)? - Generally in all cases were you use a ball as a counterpart the longer the wear test take the deeper the ball will go into the samples. As a consequence the contact area between ball an sample increases, which means that the contact pressure decreases and this can result in a decrease in wear rate. Other processes like heating of the sample with time or chemical reaction at the surface may also has a time dependence, that the wear rate can change with the sliding distance.

Dear Dr. Schiffmann, thank you for the valuable insight. I would be really grateful if you could suggest few papers related to your info. Thank you very much. 

In some cases, roughness in between ball and sample surface could be one of the reason for test result behaving in abnormality. I suggest, you check on both surface roughness to see whether you can find any differences in between different test parameters. I hope it will be helpful.