I am polishing with emery papers with different grit sizes followed by diamond polishing and colloidal sols after ultrasonication with no scratch
After that when I go to EBSD CI is not coming. Please tell me about this problem with a solution.
Do you see the Kikuchi pattern by eye? If not, try adding 10% H2O2 to the oxide polishing solution and repolish.
Also, CI is a lottery between the phases you put into the expected phases. If you put very similar phases, the CI will be low even if your preparation is good.
You can try vibropolishing your samples for 4-6 hours with 90% OPS and 10% H2O2 with 30% concentration.
Titanium do not like excessive grinding and polishing so use these steps:
- 220 grit grinding
- 9µm polishing
- OPS polishing with 1 part H2O2 and 5 parts OPS solution. (Last 30 seconds only with distilled water.)
- Clean the sample under warm water with piece of cotton & dishwasher soap.
- Vibropolishing 4-6 hours with some H2O2 & OPS.
- Clean the sample under warm water with piece of cotton & dishwasher soap.
Most of it will be trial and error. Chemical resistant polishing clothes will wear out fast with increasing H2O2. So find your optimum with trial and error.
Dear Md Alam please do recommend my answer if helpful
Polishing Ti-6Al-4V alloy, particularly for Electron Backscatter Diffraction (EBSD) analysis, requires meticulous preparation to achieve a smooth, deformation-free surface suitable for accurate crystallographic characterization. Here is a step-by-step guide for polishing 3D-printed Ti-6Al-4V alloy:
### Step-by-Step Polishing Process
**1. Sample Preparation:**
- **Sectioning:** Carefully section the 3D-printed Ti-6Al-4V sample to a manageable size. Use a low-speed precision saw with a diamond blade to minimize induced stress.
- **Mounting:** Mount the sample in a conductive mounting medium if you plan to use SEM. Conductive mounts help reduce charging effects during EBSD analysis.
**2. Grinding:**
- **Initial Grinding:** Begin with coarse grinding to remove surface irregularities and 3D printing artifacts.
- Use SiC papers starting with a grit size of 320 or 400.
- Progress through finer grit sizes (e.g., 600, 800, 1200).
- **Intermediate Grinding:** Use finer SiC papers (up to 2500 or 4000 grit) to smoothen the surface further.
**3. Polishing:**
- **Rough Polishing:** Use diamond suspensions on a polishing cloth.
- Start with a 6 µm diamond suspension and polish for 5-10 minutes.
- Rinse the sample with distilled water and clean it ultrasonically between steps.
- **Intermediate Polishing:** Proceed with a 3 µm diamond suspension for another 5-10 minutes.
- **Fine Polishing:** Use a 1 µm diamond suspension to achieve a mirror-like finish.
**4. Final Polishing (Colloidal Silica):**
- Use a colloidal silica suspension (0.05 µm) on a vibratory polisher for 15-30 minutes.
- This step is crucial for removing any residual deformation layer and achieving a deformation-free surface suitable for EBSD.
- Rinse thoroughly with distilled water and dry the sample gently.
### Cleaning and Drying:
- After polishing, clean the sample in an ultrasonic bath with distilled water or ethanol.
- Dry the sample with a gentle stream of compressed air or under a low-temperature heat lamp.
### Quality Check:
- Inspect the surface under an optical microscope to ensure no scratches or deformations are present.
- Perform a quick EBSD scan to verify the quality of the surface preparation.
### Tips for Successful Polishing:
1. **Consistent Pressure:** Apply consistent, moderate pressure during grinding and polishing to avoid introducing new deformation.
2. **Cleanliness:** Keep the workspace clean and avoid cross-contamination between different polishing steps.
3. **Patience:** Take your time with each step to ensure the highest quality surface finish.
4. **Optimize for 3D Printing Artifacts:** Pay special attention to removing any surface defects unique to 3D printing processes, such as layer lines or porosity.
### EBSD Analysis:
- Ensure the sample is properly mounted in the SEM and that the surface is conductive to prevent charging.
- Optimize the EBSD parameters, including accelerating voltage, working distance, and step size, to achieve high-quality diffraction patterns.
By following this meticulous polishing procedure, you can prepare Ti-6Al-4V alloy samples fabricated by 3D printing for high-quality EBSD analysis, ensuring accurate and reliable crystallographic information.
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