Zirconia

MS Grade - 82 HRA

Mg-PSZ, a Magnesia-Partially Stabilized Zirconia, contains 3.5 wt% MgO in ZrO2 and is known for its remarkable transformation toughening. It's ideal for high-strength applications due to its superior mechanical strength, outstanding wear, abrasion, and corrosion resistance, coupled with high impact toughness and low thermal conductivity. This makes it perfect for use in harsh chemical processing and refining environments, particularly in valves, pumps, and liners. Additionally, it's widely used in various tooling applications for metal forming and dry cell battery production.

 STEP 1: CUTTING THE WORKPIECE 

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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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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.

IN THE END

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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When starting with a flat sample in the Zirconia grinding process, the 40 µm abrasive is used. If the sample is not flat, you should start with a coarser grit in order to get a flat surface, for example, a 54µm abrasive.

It's crucial to remember that the diameter of the sample determines the amount of force that is used during grinding; in this case, the sample is 30 mm in diameter. It's also advised to turn the plate and sampler holder in a clockwise direction to avoid causing the sample undue harm.

Pre-polishing is not neccessairy in this step for this material.

 STEP 4: PRE-POLISHING AND POLISHING 

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In the polishing steps for Zirconia, 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. During the 9 µm phase, it is recommended to rotate the sample in a counter-clockwise direction to eliminate scratches from coarser grits. Conversely, for the 2 µm, a clockwise rotation is advised to prevent excessive damage to the sample. 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.

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.