Tungsten-Nickel Cemented Carbide with Strong Acid and Alkali Resistance

The flow meter is used to measure the flow rate and speed of the liquid when it is flowing. Typically, the movement shaft of a flow meter is made of stainless steel. It is well known that stainless steel has good corrosion resistance. The corrosion resistance of stainless steel depends on the alloying elements contained in the steel. Chromium is the basic element for obtaining corrosion resistance of stainless steel. In addition to chromium, commonly used alloying elements include nickel, molybdenum, titanium, niobium, copper, and nitrogen to meet the requirements of stainless steel structure and properties for various applications.

However, the flow shafts, which are exposed to chemicals such as strong acids and alkalis for a long time, would be corroded. In addition, stainless steel is added with other alloying elements, which makes the steel material impure, so there will be deviations in the magnetic field, resulting in inaccurate measurement. In order to improve the acid-base resistance of the material without magnetic properties, some scholars have proposed a preparation method of tungsten-nickel cemented carbide by:

The raw materials are prepared by weight percentage: 90% tungsten alloy (WC) powder, 9.6% nickel (Ni) powder and 0.4% chromium carbide (Cr3C2) powder; after the raw materials are subjected to mixed ball milling for 36 hours, the material is precipitated for 24 hours and dried for 100 minutes. ± 5 minutes, the temperature is controlled at 85 ° C ± 5 ° C; and then mixed with 10 ml of glue per 1 Kg of mixed raw materials, add SBS-modified binder (0.1Kg of SBS-modified binder per 1Kg of mixed raw materials); finally sintered in a vacuum furnace, control from 300 ° C to 1450 ° C, and then cool down to normal temperature, the product is released.

The WC powder has a particle size of 2.3 to 2.8 μm, the Ni powder has a particle size of 1.5 to 2.0 μm, and the Cr3C2 has a particle size of 2.0 to 2.6 μm.

Because WC powder, Ni powder and Cr3C2 powder are used as alloying elements, the acid and alkali resistance of the material can be improved, the service life is greatly prolonged, and nickel is used instead of the conventional cobalt in the material, so that the material is not magnetic, so it is made. The tungsten-nickel cemented carbide can be used to make the movement shaft of the acid-base flow meter and the movement shaft of the instrument that needs to avoid magnetic interference.

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