Thermal Spray Coating (Ceramic Coating)
Purpose：Observe the microstructure of
thermal spray coatings. Thermal spraying is a technique that uses high-energy
heat sources (e.g., flame, plasma, or electric arc) to heat spray materials (ultrafine powders, wires, or rods of
metals, non-metals, or ceramics) to a molten state. The atomized particles are
accelerated to high velocities and sprayed onto a substrate to form functional
surface coatings. Metallographic testing evaluates the coating-substrate
interface, coating microstructure, porosity, cracks, and particle melting.
Samples undergo cutting (TableCut200), mounting (TJ2568 cold-curing resin),
grinding/polishing (Alpha610), and microscopic examination (MN80 metallographic
microscope).
Basic
Guide：
Cutting：1.Use
resin-bonded alumina cutting wheels for metallic coatings or diamond cutting
wheels for ceramic coatings. Refer to the Trojan Cutting Guide for specific models.
2.Select
pulse mode for cutting, with a recommended maximum cutting speed ≤0.25 mm/s.
Mounting：Use
high-edge-retention cold-curing epoxy resin with the pressure cold-mounting
equipment.
Grinding：1.Begin
with P400 diamond grinding discs until the sample surface is flat and cutting damage is
fully removed.
2.Continue
fine grinding
with a POH 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 alcohol and dry with a blower to remove residue.
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 thermal spray coatings exclusively to such samples.
7.After
using silica polishing suspension, clean the bottle cap thoroughly before
sealing.
