Borosilicate Glass

Type 3.3 - 5 MOHS

This glass type is highly resistant to harsh chemicals and contains a significant amount of silica; it also has a substantial boron oxide component.. Due to its low thermal expansion rate and excellent resistance to thermal shock, it can operate at temperatures up to 450 °C for extended periods. This makes it ideal for stable temperature environments.

 STEP 1: CUTTING THE WORKPEACE 

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Wet abrasive cutting stands out as the most suitable method for materialographic cutting due to its minimal impact on the specimen in relation to the processing time. This technique involves the use of a cut-off wheel comprising abrasive particles and a binder.

DURING THE PROCEDURE

• The sample should accurately reflect the characteristics of the original piece or component from which it is derived

• The cut-off wheel should experience minimal wear and tear

• The cut-off wheel should not face obstruction during the cutting process

• There should be no occurrence of thermal damage or burning on the surface of the specimen

• The specimen should be cool to the touch upon extraction from the machine

• The presence of burrs should be minimized

• The resulting surface should exhibit a uniform and smooth appearance with consistent scratches

 STEP 2: MOUNTING 

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RECOMMENDED

We recommend you to mount your samples the most convenient way, giving attention to the heat resistance of the sample material, although, if a mounting press is unavailable, cold mounting becomes the sole viable option. Conversely, with access to a mounting press, the selection of mounting material can be refined based on specific attributes.

A crucial factor to consider is the abrasion rate, which denotes the speed at which material is ground or polished away. Ideally, the chosen mounting material should closely match the abrasion rate of the sample material. It is essential to recognize that the abrasion rate differs from the hardness of the sample.

As for the resin needs, we recommend the use of Epoxy resin as Epoxies offer a robust mounting solution with high resistance to chemicals and abrasion. Although they typically require a longer setup time compared to other castable materials, they exhibit superior flow and minimal shrinkage properties. For mounting challenging samples, long-cure epoxies are employed, and they can be introduced into a vacuum environment to eliminate trapped air and address voids.

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If necessary, calibrate the sample with a coarser grit to make sure flat surface is achieved. The workpiece should be perfectly flat.

 STEP 3: PLANAR GRINDING AND LAPPING 

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In the grinding steps for Borosilicate Glass, a 40 µm abrasive should be initially employed to achieve a flat surface. Following the 40-grit, the subsequent step involves the use of a 20 µm abrasive as a pre-polishing step.

It's important to note that the applied force during grinding depends on the diameter of the sample, and in this instance, the sample has a diameter of 30mm. Additionally, to prevent excessive damage to the sample, it is recommended to rotate the plate and the sample holder clockwise.

 STEP 4: PRE-POLISHING AND POLISHING 

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In the polishing steps for Borosilicate Glass, the process initiates with a 9 µm abrasive.

Subsequently, following the 9 µm, a 2 µm abrasive is employed. The applied force during polishing is contingent on the diameter of the sample, with the current sample having a diameter of 30mm.

It is crucial that all scratches align in the same direction, and if not, repeating the preceding step becomes necessary.

 STEP 5: FINAL POLISH 

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Finally, a suitable pad with a colloidal silica solution is utilized to clean and execute the last polishing step, providing a mirror-like finish to the stainless steel 316L sample.

Materialography

The term materialography used today is a factual extension of metallography, which include many other groups of materials, such as ceramics, plastics and composite materials that are examined in the same way.​ Materialography is the science of examining a material's microstructure, which is its internal composition at a microscopic level. By polishing and analyzing a material's surface, materialography helps engineers understand properties like strength, corrosion resistance, and potential failure points.