Pure Tin
Purpose：Observe the microstructure of pure
tin. Tin exhibits excellent ductility, low melting point, softness, and
corrosion resistance. Tin and its alloys are widely used in bearing
manufacturing, aerospace, electronics, and other fields. Pure tin samples undergo
cutting (TableCUT-200), mounting (TJ2228 cold-curing resin), grinding/polishing
(Alpha-610), and final vibratory polishing (VP430 vibratory polisher). The
sample surface is then examined under a microscope. The microstructure is
observed under polarized light mode.
Basic
Guide：
Cutting：Pure
tin is soft. Use an S20 silicon carbide abrasive cutting wheel. Refer to the
Trojan Cutting Guide for specific
model selection.
Mounting：To
observe internal structures, use low-reaction-temperature cold-curing resin
(tin and its alloys are temperature-sensitive).
Grinding：1.Start
with finer grits
(P800 sandpaper) and progress to P2500. Apply wax to the sandpaper to prevent
embedded abrasive particles.
2.Clean
the sample, sample holder, and hands after each grinding step.
Polishing：1.Before
polishing, clean the polishing cloth, sample holder, and hands. Repeat cleaning
after each polishing step.
2.Do
not mix polishing suspensions with different
abrasive particles.
3.Rinse
the sample surface with alcohol and dry with a blower to remove water residue
and prevent oxidation.
4.After
each polishing step, inspect under a metallographic microscope to ensure that
the scratch size matches the abrasive grit and direction is random.
5.If
surface blurring occurs after ET white synthetic velvet cloth for polishing,
the sample and working disc can be repeatedly polished in the same direction
for 3-5 minutes.
6.Clean
the polishing cloth with running water and a soft brush after use, then
air-dry.
