Mg Polishing & Etching

Loss Prevention

1. Safety glasses should always be worn in the metallography labs
2. Gloves should always be worn when working with chemicals
3. Wear a respirator when working with powders

Procedure

1. Place the sample face down on a cotton round in a beaker of ethanol and leave the beaker in the ultrasonic cleaner for five minutes, then dry with compressed air
2. Secure 240 silicon carbide pad in the polisher and apply a load of 20 N to the sample, force adjustments are made by turning the wheel above the sample. The height of the bolt in the slot above the sample indicates the force applied (figure 1)

Figure 1: Automatic Polisher

1. Run polisher for 2 minutes with water constantly rinsing the pad, make sure the head is locked in place
2. Remove sample and rinse with water, fold and throw away the polishing pad
3. Repeat steps 2-4 with 320, 400, 600, and 800 polishing pads and 1 minute intervals
4. Repeat step 1
5. Polish the sample using a diamond pad with RedLube (Methanol Propylene Glycol) for 5 minutes, do not rinse the pad with water
6. Repeat step 1
7. Make a suspension of roughly ⅓ cup alumina powder in 20 fl oz water
8. Polish the sample with a flocked pad for 5 minutes, keep the pad wet with the suspension. Do not add water except to rinse the basin
9. Repeat step 1
10. In the fume hood, use a cotton swab to apply a small amount of nital for several seconds
11. Rinse the sample with water, then spray with ethanol and dry with a hair dryer