Views: 2 Author: Site Editor Publish Time: 2022-01-04 Origin: Site
Metallographic preparation is the basis for the observation of the microstructure of materials, as well as an important method for studying material properties and detecting defects and failures. In order to further improve the safety of tungsten-zirconium alloy metallographic sample preparation and enable it to quickly and clearly display the microstructure, the researchers proposed a new preparation method. Specific steps are as follows:
1) Sampling: take a small sample, the cutting surface is the inspection surface;
2) Grinding: Grind the inspection surface with sandpaper to remove surface scratches. After grinding, put the sample in alcohol for ultrasonic cleaning and then take it out and dry it;
3) Rough polishing: rough polishing with diamond spray polishing agent, rotating speed 300～500r/min; after rough polishing, put the sample in alcohol for ultrasonic cleaning and then take it out and blow dry;
4) Fine polishing: Use chromium trioxide polishing agent for fine polishing at a speed of 100～150r/min; after finishing the fine polishing, put the sample in alcohol for ultrasonic cleaning and then take it out and dry it;
5) Final polishing: use silicon emulsion suspension for final polishing at a speed of 100～150r/min; after the final polishing, put the sample in alcohol for ultrasonic cleaning and then take it out and blow dry. Observe that the particle size is 1～3μm containing tungsten Mutually.
The precautions for this preparation technique are as follows:
(1) The grinding process includes:
Coarse grinding; use 180 mesh or 200 mesh silicon carbide water sandpaper to coarsely grind the inspection surface of the sample along the vertical scratch direction;
Fine grinding; rotate the sample 90 degrees, use one or more of 240 mesh, 400 mesh, 600 mesh, and 800 mesh silicon carbide water sandpaper to perform fine grinding on the inspection surface of the sample one time or more. In the second time, the mesh number of the next sandpaper is higher than that of the previous sandpaper. Water is used as a lubricant during the grinding process. After the previous time is completed, the sample is rotated 90 degrees in the same direction.
Fine grinding: Use 600 mesh, 800 mesh, 1000 mesh silicon carbide metallographic sandpaper or several kinds of soap as the lubricant for one or more passes to fine grind the inspection surface of the sample; when multiple passes are used, after The mesh number of one sandpaper is higher than that of the previous sandpaper.
(2) Step 4) Preparation steps of chromium trioxide polishing agent:
Mixed solution preparation: add chromium trioxide to water to form a mixed solution;
One-time filtration: Pour the mixed liquid into a 100-300 mesh single-layer copper mesh to filter, and save the filtered suspension;
Secondary filtration: Pour the suspension after the primary filtration into a double-layer copper mesh with the same mesh number as the single-layer copper mesh or higher than that of the single-layer copper mesh, and filter again; the suspension after the secondary filtration is allowed to stand for 20～ For 60 minutes, remove the viscous part of the lower layer and use it as a chromium trioxide polishing agent.