Powder Metallurgy Steel
Purpose：Test
porosity and observe the microstructure of powder metallurgy samples. Powder
metallurgy involves forming and sintering metal powders (or mixtures of metal
and non-metal powders) to produce metal components or materials. Key advantages
include the ability to form special materials (e.g., refractory metals,
pseudo-alloys, porous materials) and ensure uniform composition distribution.
Samples undergo cutting (CT-250V), mounting (TJ2228 cold-curing resin and
ThetaVAC-2 vacuum cold mounting machine), grinding/polishing (Alpha610), and
porosity measurement via metallographic microscope (MN80). Etching with 4%
nitric acid alcohol solution reveals the microstructure.
Basic
Guide：
Cutting：1.Use
a resin-bonded alumina cutting wheel for powder metallurgy steel. Refer to the
Trojan Cutting Guide for specific
models.
2.For
automated cutting, select pulse mode with a maximum cutting speed ≤0.25 mm/s.
Mounting：Use
high-edge-retention cold/hot mounting resin.
Grinding：1.Begin
with P400 silicon carbide sandpaper until the sample surface is flat and cutting damage is
fully removed.
2.Continue
fine grinding
with a POS disc + 9 µm diamond polishing suspension.
3.Clean
the sample, sample holder, and hands after each grinding step.
Polishing：1.Clean
the polishing cloth, sample holder, and hands before polishing. Repeat cleaning
after each step.
2.Do
not mix polishing disks with different
abrasive particle sizes.
3.Rinse
the sample surface with isopropyl alcohol and dry with a blower to remove
residue and prevent corrosion.
4.After
each polishing step, inspect under a metallographic microscope to ensure
scratch size matches the abrasive grit and direction is random.
5.Clean
polishing cloths with running water and a soft brush after use, then air-dry.
6.Dedicate
polishing cloths used for powder metallurgy steel exclusively to such samples.
