Application framework for selection and method discussions; not a customer test report.
Purpose
Pore morphology, structure and brittle-material sections.
Preparation route
Define the section and evaluate cutting and support. Select preparation methods that retain pores and edges.
Checkpoints
Distinguish original pores from preparation pull-out. A two-dimensional image result is not automatically interchangeable with another porosity method.
Equipment stages
Cutting → Mounting → Grinding and polishing → appropriate microscopy and testing.
Record sampling position, consumables, actual settings and images. Evaluate using the agreed method.
Typical inspection scenarios
95% alumina structural ceramic and ceramic foam filter
- Challenge
- The material is extremely hard and brittle, so conventional cutting easily causes edge chipping and induced cracks; during grinding and polishing, grains pull out and pore edges collapse, which inflates and falsifies porosity and pore-size measurements.
- Preparation & method
- Cut on a precision saw with a diamond blade at low speed, low feed and ample coolant, using multiple shallow passes for brittle pieces. Vacuum-impregnate with low-viscosity epoxy cold mounting resin to infiltrate pores and consolidate the skeleton so grains do not pull out during preparation. Grind gently with SiC papers from P400 to P1200, polish with 6 μm then 1 μm diamond, and examine unetched: measure apparent porosity and pore-size distribution by image analysis and observe grains and grain-boundary phases.
- Reference standards
- GB/T 25995 Test methods for density and apparent porosity of fine ceramics; ISO 13383 Fine ceramics — Microstructural characterization; ASTM E3 Standard Guide for Preparation of Metallographic Specimens
Reaction-bonded silicon carbide (SiSiC) seal ring
- Challenge
- The SiC skeleton (extremely hard) coexists with free silicon (soft); the hardness mismatch causes silicon to spall and SiC grains to pull out during preparation, so the true interfacial bonding state is hard to preserve; free-silicon content and residual porosity require accurate quantification, and preparation relief or contamination directly corrupts image analysis.
- Preparation & method
- Cut on a precision saw with a diamond blade at low speed and low feed, with ample coolant and multiple shallow passes. Vacuum-impregnate with low-viscosity epoxy cold mounting resin to infiltrate micropores and consolidate the skeleton. Grind gently with SiC papers from P400 to P1200; polish stepwise with 6 μm, 3 μm and 1 μm diamond, finishing with 0.05 μm colloidal silica where needed to remove two-phase relief. Examine unetched under bright field: SiC grains appear angular and free silicon as a light continuous phase, with polarized/dark field aiding discrimination; quantify the free-silicon area fraction and residual porosity by image analysis; measure the hardness of the SiC and silicon phases separately by micro-Vickers (HV1) for comparison.
- Reference standards
- ISO 13383 Fine ceramics (advanced ceramics, advanced technical ceramics) — Microstructural characterization; GB/T 25995 Test methods for density and apparent porosity of fine ceramics; ASTM E3 Standard Guide for Preparation of Metallographic Specimens
Scenarios are method examples, not customer test reports; confirm the process per specimen.
MICROCRE learning notes · confirm the method for the specimen.