Ball Milling method for synthesis of nanomaterials
There are different methods for synthesis of nanomaterials. Today I will discuss the ball milling method.
Steps in ball milling method;
1. As the name suggests, the ball milling method consists of balls and a mill chamber. Therefore over all a ball mill contains a stainless steel container and many small iron, hardened steel, silicon carbide, or tungsten carbide balls are made to rotate inside a mill (drum).
2. The powder of a material is taken inside the steel container. This powder will be made into nanosize using the ball milling technique. A magnet is placed outside the container to provide the pulling force to the material and this magnetic force increases the milling energy when milling container or chamber rotates the metal balls.
3. The ball to material mass ratio is normally maintained at 2 ratio1.
3. These silicon carbide balls provide very large amount of energy to the material powder and the powder then get crushed. This process of ball milling is done approximately 100 to 150 hrs to get uniform fine powder.
4. Ball milling is a mechanical process and thus all the structural and chemical changes are produced by mechanical energy.
Advantages of ball milling process:
1. Nanopowders of 2 to 20 nm in size can be produced. The size of nanopowder also depends upon the speed of the rotation of the balls.
2. It is an inexpensive and easy process.
1. As the process is not so sophisticated, therefore the shape of the nanomaterial is irregular.
2. There may be contaminants inserted from ball and milling additives.
3. This method produces crystal defects.