Selection of Sliding Bearings for Submersible Pumps-- Silicon Carbide Ceramics

Bearing Material Selection

The choice of bearing material is essential for its reliable operation. For many years, materials such as rubber, bronze and ceramics have been used to make bearings. Different materials have different effects. Among them, ceramics and graphite are widely used in bearing manufacturing.

Silicon Carbide Bearing

There are many types of ceramic materials including oxides, borides, and nitrides. The typical ceramic material used for bearing manufacturing and achieving good performance is silicon carbide. Silicon carbide is sintered at high temperature in a resistance furnace using quartz sand, petroleum coke and other raw materials. It is a hexagonal crystal with a relative density of 3.20 to 3.25 g / cm3 and a micro hardness of 2 840 to 3320 kg / mm2. Silicon carbide has the advantages of high hardness, good wear resistance, corrosion resistance, oxidation resistance, and low temperature creep. It has been widely used as a wear part in many fields.

In general, although the submersible pump sliding bearing uses external water as the flushing fluid to lubricate the bearing and take away heat, the medium can still enter the gap of the sliding bearing. The solid particles contained in the medium usually cause serious abrasive wear of the bearing and shorten the bearing life.

Sand water abrasion experiments show that the friction coefficient of silicon carbide sintered at atmospheric pressure under sand water lubrication conditions is 0.05 to 0.13, which is incomparable for graphite, rubber, bronze and other materials. This experiment shows that silicon carbide bearings have better adaptability to abrasive wear of solid particles.

It is worth noting that the thermal expansion coefficient of silicon carbide is about 1/3 to 1/4 of the thermal expansion coefficient of steel. Under high temperature conditions, due to uneven expansion, the silicon carbide shaft sleeve and bushing will be severely loosened and tightened with the matching metal parts. In severe cases, the shaft sleeve will be expanded and cracked, and the bearing will lose its function.

Advanced Ceramic Materials (ACM) Corporation supplies high-quality and consistent silicon carbide ceramic products to meet our customers’ R&D and production needs. Please visit https://www.preciseceramic.com/ for more information.

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