Removal of residual colloidal silica from metallography sample

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In summary, the speaker is experiencing issues with residual colloidal silica on a metallography sample that was mounted in Bakelite. They used a Vibromet for polishing, but are now having trouble with EDS and high-res SEM imaging due to leftover colloidal silica. They have tried using a fresh polishing cloth and water, but it has not fully cleaned the sample. They are asking for any tips or tricks to clean it up, and someone suggests using an ion mill followed by EDS.
  • #1
Dave_H
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Hey there,
I've been having some issues with residual colloidal silica on a metallography sample (mounted in Bakelite). I used a Vibromet for several hours as my final stage of polishing which gave me a really nice polish, but now I'm having trouble with EDS and high-res SEM as I'm trying to image primary/eutectic silicon phase and I have some residual colloidal messing things up.

I have tried just using a fresh polishing cloth and water, but that hasn't fully cleaned it up. Just wondering if anyone has any neat tricks to clean up a sample?

Thanks,
 
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  • #2
Ion mill followed by EDS.
 
  • #3


Hello,

Thank you for reaching out with your issue. Residual colloidal silica can indeed cause problems with EDS and SEM imaging, as it can interfere with the detection of elements in the sample.

One solution you can try is using an ultrasonic bath with a mild detergent solution. This can help to break down and remove the residual silica from the surface of the sample. You can also try using a surfactant solution to help disperse the silica particles.

Another option is to use a mild acid, such as dilute hydrochloric acid, to etch away the silica. However, this method should be used with caution as it can also etch away some of the sample surface.

It may also be helpful to ensure that all equipment and materials used in the polishing process are thoroughly cleaned and free of any residual silica before use.

I hope these suggestions are helpful in resolving your issue. Best of luck with your analysis.
 

FAQ: Removal of residual colloidal silica from metallography sample

1. How does colloidal silica get deposited on metallography samples?

Colloidal silica can be deposited on metallography samples through various means, such as rinsing with water containing silica particles or using polishing compounds that contain silica. It can also be introduced through contamination from the environment or handling.

2. What are the potential effects of residual colloidal silica on metallography samples?

Residual colloidal silica can negatively affect the accuracy and clarity of metallography samples. It can cause interference in microscopic analysis and affect the interpretation of results. In addition, it can also alter surface properties, such as roughness and reflectivity.

3. How can residual colloidal silica be removed from metallography samples?

There are several methods for removing residual colloidal silica from metallography samples, including chemical treatments, sonication, and mechanical brushing. The most common method involves rinsing the sample with a dilute acid solution, followed by thorough rinsing with deionized water.

4. Can the removal of residual colloidal silica affect the composition of the metallography sample?

In most cases, the removal of residual colloidal silica will not significantly alter the composition of the metallography sample. However, it is always important to use a mild and controlled approach when removing any contaminants to minimize potential effects on the sample.

5. How can one ensure complete removal of residual colloidal silica from metallography samples?

To ensure complete removal of residual colloidal silica, it is essential to thoroughly rinse the sample with deionized water after any chemical treatment or mechanical brushing. Additionally, microscopic analysis can be used to check for any remaining particles on the sample surface.

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