Tech Team · Kintek Solution

Preparing KBr (potassium bromide) pellets for observation, particularly for techniques like FTIR (Fourier Transform Infrared Spectroscopy), involves a precise and methodical process. The goal is to create a transparent pellet that allows for accurate spectroscopic analysis. Here's a summary of the process:

To prepare KBr pellets, you start by grinding the KBr powder to a fine consistency, ensuring it is dry and free of contaminants. The finely ground KBr is then mixed with the sample material in a specific ratio (typically 100:1 KBr to sample). This mixture is placed into a die set, often 7mm in diameter, and subjected to high pressure (15-35 tons) using a hydraulic press. The pressure compresses the mixture into a solid, transparent pellet. The die set, made of hardened nickel-based alloy with optically polished anvil faces, ensures the pellet is uniform and suitable for spectroscopic analysis. The resulting pellet is then ready for observation.

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Key Points Explained:

1. Grinding the KBr Powder:

   • The first step involves grinding the KBr powder to a fine consistency. This ensures that the KBr particles are small enough to form a uniform pellet when pressed.
   • The grinding process should be done carefully to avoid contamination, as impurities can affect the spectroscopic results.

2. Mixing the Sample with KBr:

   • After grinding, the KBr powder is mixed with the sample material. The typical ratio is 100 parts KBr to 1 part sample, ensuring the sample is evenly distributed within the KBr matrix.
   • This mixture is crucial for creating a pellet that is both transparent and contains a representative amount of the sample for analysis.

3. Using the Die Set:

   • The mixture is then placed into a die set, which is typically made of a hardened nickel-based alloy. The die set includes anvils with optically polished faces to ensure the pellet is smooth and uniform.
   • Die sets are available in various sizes, such as 7mm, 4mm, or 2mm, depending on the specific requirements of the analysis.

4. Applying Pressure:

   • The die set containing the KBr-sample mixture is placed in a hydraulic press. A pressure of 15 to 35 tons is applied to compress the mixture into a solid pellet.
   • The high pressure ensures that the pellet is dense and transparent, which is essential for accurate spectroscopic observation.

5. Finalizing the Pellet:

   • Once the pellet is formed, it is carefully removed from the die set. The resulting pellet should be uniform, transparent, and free of cracks or defects.
   • The pellet is now ready for spectroscopic analysis, such as FTIR, where it will provide clear and accurate data for observation.

By following these steps, you can prepare high-quality KBr pellets that are suitable for spectroscopic observation, ensuring accurate and reliable results.

Summary Table:

Step	Description
1. Grinding KBr Powder	Grind KBr to a fine consistency, ensuring it is dry and free of contaminants.
2. Mixing Sample	Mix KBr with the sample in a 100:1 ratio for even distribution.
3. Using Die Set	Place mixture in a die set (e.g., 7mm) with polished anvil faces.
4. Applying Pressure	Compress the mixture under 15-35 tons of pressure using a hydraulic press.
5. Finalizing Pellet	Remove the uniform, transparent pellet for FTIR analysis.

Need help preparing KBr pellets for your FTIR analysis? Contact us today for expert guidance!