1. Friction compatibility

The performance of preventing adhesion and forming boundary lubrication when bearing diameter is in direct contact with bearing bush.The material factors affecting the friction compatibility of the friction pair are as follows:

(1) The metallurgical difficulty of forming alloys. 

(2) Affinity of materials and lubricants. 

(3) The friction factor of the pair material under the condition of no lubrication. 

(4) Microstructure of the material. 

(5) Thermal conductivity of materials. 

(6) The size of the surface energy of the material and the characteristics of the oxide film. 

2. The embedding

The ability of a material to permit the clamping of foreign hard particles in the lubricant to prevent scratch or/and abrasive wear.For metal materials, low hardness and low elastic modulus are good for embedability, while non-metallic materials are not necessarily so. For example, carbon and graphite have low elastic modulus but poor embedability.The friction amplitude of sliding bearing is usually formed by soft material and hard material, and the bearing bush is usually made of soft material. 

3. The break-in

In the process of the grinding of axle diameter and axle bush, the machining error, coaxiality error and surface roughness parameter value are reduced to make the contact even, thus reducing the friction force and wear rate. 

4. Friction compliance

The elastoplastic deformation of the surface compensates for the poor initial fit of the sliding friction surface and the deflection of the shaft.Materials with low modulus of elasticity have better compliance. 

5. Wear resistance

The abrasion resistance of a composite material.Under specified wear conditions, wear rate or reciprocal of wear degree and wear amount is used to represent wear resistance. 

6. Fatigue resistance

The resistance of a material to fatigue failure under cyclic loading.Under the service temperature, the strength, hardness, impact strength and uniformity of the bearing bush material against fatigue are very important.Materials with good break-in and embeddability usually have poor fatigue resistance. 

7. The corrosion resistance

The resistance of a material to corrosion.When used in the atmosphere, lubricants gradually oxidize to produce acid, and most lubricants contain extreme pressure additives that corrode bearing materials, so bearing materials need to be resistant to corrosion. 

8. Cavitation resistance

When the bubbles in the liquid break near the solid surface, local impact pressure or local high temperature will result in cavitation wear.The ability of a material to resist cavitation wear is called cavitation resistance.In general, copper-lead alloys, bearing alloys and al-Zn-Si alloys exhibit better cavitation resistance. 

9. Compressive strength

Ability to withstand unidirectional loads without being crushed or dimensionally unchanged.