Ball Milling (Top-Down) Method

Contents

Introduction

S/V ratio

Quantum Confinement

Synthesis of nano materials

Ball milling method

Chemical Vapor Depositon

Sol-Gel Method

X-ray diffraction

Scanning Electron Microscope

Transmission Electron Microscope

Applications of Nano materials

1M Previous Years' Questions

Ball milling, also called mechanical crushing is a popular method to synthesize nanopowders of various solid materials. This comes under Top-Down approach of nanomaterial synthesis. The following is the process flow to synthesize nanomaterial by ball milling method.

Ball-milling
  • It consist of a drum which can rotate coaxially. The materials in raw form (big particle size) which need to be grinded into the nanoform has to be taken inside the drum.
  • The grinding medium is usually iron balls or zirconia beads. They come with various diameter.
  • A mixing medium is also required in most of the cases. Usually Ethyl Alcohol, Acetone, Distilled water is used for this purpose.
  • The milling machine connected to a motor which will rotate the drum containing raw powder, beads at high RPM, which results formation of nanopowder.
  • Ball milling takes typically much time (8 hours - 24 hours) in order to obtain fine nanopowder.
  • By changing the RPM, duration of milling, size of zirconia bead, we can control the average particle size in nanopowder.

Advantages
  • Ease of synthesis
  • Low cost
  • Non-toxic
  • Low temperature processing
Disadvantages
  • Time consuming
  • Loss of materials
  • Chances of contamination is more
  • Non-uniform particle size distribution