Dear metallographic Experts,
It is said that the Pure Aluminium metal , a softest material , hence the diamond particles get stuck plastically after 1 micron diamond polishing. Experts are saying, this problem can be resolved by polishing using colloidal silica.Even i tried the previous step, eventually the diamond particles didn't go off.
I also have tried with alumina suspension polishing , in which another issue i have found , that is i am not able to obtain a mirror like finish even after a long time polishing.
What should be done,Please help me in this and give me suggestions.
Thank you for understanding.
You do not need to "eradicate" diamond particles. They should be removed by subsequent polishing steps if you do them correctly. Cleanness is a key to success. Wash specimens after each step. Do not contaminate your polishing cloth with abrasive particles from your previous step. Do not apply too much pressure. Do not overpolish.
You can find some details here:
https://www.buehler.com/aluminum-metallographic-specimen-preparation-and-testing.php
http://www.metallographic.com/Procedures/Aluminum%20Description.htm
The attached Application Note issued by Struers may possibly be found of some help:
If you use hard resilient cloths this may lodge the diamonds into the Al matrix by plastic deformation. In this case try to exchange with soft cloths of low resilience. Also adjust the force you apply to the sample.
Hi!
According to tribology fundaments, friction between two materials originates wear. This happens because of the asperities. Asperities are roughness differences in the roughness profile. In this particular case, diamond particles can very well fit into the work part, due to their small size. As told on this thread, plastic deformation can cause particles to logde into Al surface. Micro-deformation of the cristalline lattices create perfect places for diamond particles to get stuck in.
Ways to minimize the problem
-Polish using lubrication
-minimize normal force applied between the two bodies
-Reduce rotating speed of the tablet
-before using diamond impregnated cloth, perform more polishing steps using SiC impregnated paper sheets. If you use a higher mesh polishing before you get to the diamond polishing, you will be reducing the depth of the asperities, therefore, minimizing the problem you are experiencing.
I hope I have helped,
Cheers,
Hugo Silva,Ph.D.
You can ultrasonicate your sample in acetone, it will definitely remove diamond particles.
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