The bearing materials used in centrifugal pumps are mainly divided into two categories: metallic materials and non-metallic materials.

Metallic Material

Metal materials commonly used metal materials for sliding bearings include bearing alloys (also known as Babbitt alloys or white alloys), wear-resistant cast iron, copper-based and aluminum-based alloys.

1. Bearing Alloy

The main alloy components of bearing alloys (also known as Babbitt alloys or white alloys) are tin, lead, antimony, copper, antimony, and copper, which are used to improve the strength and hardness of the alloy. Most of the bearing alloy elements have low melting points, so they are suitable for working conditions below 150 °C.

2. Copper-based Alloy

Copper-based alloys have higher thermal conductivity and better wear resistance than steel. And the copper-based alloy has good machinability and lubricity, and its inner wall can be finished, and it is in contact with the smooth surface of the shaft. 

Non-metallic Material

1. PTFE

Has good self-lubricating properties and high thermal stability. Its friction coefficient is small, it does not absorb water, is not sticky, is not flammable, and can be used under the condition of -180~250°C. But there are also disadvantages such as large linear expansion coefficient, poor dimensional stability, and poor thermal conductivity. In order to improve its performance, it can be filled and strengthened with metal particles, fibers, graphite and inorganic substances.

2. Graphite

It is a good self-lubricating material, and because it is easy to process, and the more it is ground, the smoother it is, so it is the material of choice for bearings. However, its mechanical properties are poor, and its impact resistance and load bearing capacity are poor, so it is only suitable for light load occasions. In order to improve its mechanical properties, some fusible metals with good wear resistance are often impregnated. The commonly used impregnation materials are Babbitt alloy, copper alloy and antimony alloy. 

3. Rubber

It is a polymer made of elastomer, which has good elasticity and shock absorption. However, its thermal conductivity is poor, processing is difficult, the allowable operating temperature is below 65°C, and it needs circulating water to lubricate and cool continuously, so it is rarely used.

4. Carbide

It has a series of excellent properties such as high hardness, wear resistance, good strength and toughness, heat resistance, and corrosion resistance. Therefore, the sliding bearings processed with it have high precision, stable operation, high hardness, good strength, and durability, but they are expensive.

5. SiC

It is a new type of artificially synthesized inorganic non-metallic material. The hardness is inferior to that of diamond. It has good chemical corrosion resistance, wear resistance, high temperature resistance, high mechanical strength, good self-lubricating performance, high temperature creep resistance, small friction factor, high thermal conductivity, and low thermal expansion coefficient. It can be widely used Used in petroleum, metallurgy, chemical industry, machinery, aerospace and nuclear energy and other fields, it is often used as the friction pair material of sliding bearings and mechanical seals.