Materials commonly used in Journal Bearings need to balance abrasion resistance, fatigue resistance, thermal conductivity and compatibility with lubricating media. Different materials are suitable for different operating conditions. The main material classifications and typical application scenarios are as follows:
1.Metallic Materials
Babbitt Metal
Ingredients: Tin-based (e.g., Sn-Sb-Cu) or lead based alloys (e.g. Pb-Sn-Cu) containing soft substrates and hard particles (e.g. SnSb, Cu6Sn5).
Features: Low friction coefficient, high resistance to wear, but relatively low strength, requires to be installed in steel or copper backing.
Application: High-speed, lightweight applications (such as turbine and generator bearings), dependent on oil film lubrication.
Copper-based Alloys
Typical materials: Bronze (such as ZCuSn10Pb1), aluminum bronze (ZCuAl10Fe3).
Features: High strength, good thermal conductivity, but friction coefficient slightly higher than Babbitt metal, require good lubrication.
Application: Medium speed, medium load condition (e.g., machine tool spindles, ship propulsion shafts).
Aluminum-based alloys
Typical material: Aluminum-tin alloys (such as AlSn20Cu).
Features: Lightweight, corrosion resistance, but limited bearing capacity; surface treatment (e.g. plating) is required to improve abrasion resistance.
Applications: Aerospace field (e.g., aircraft engine bearings).

2. Powder metallurgy materials
Iron-based oil-soaked bearings
Ingredients: Iron powder mixed with copper powder and graphite sintering, porosity 10%-30%.
Features: Self-lubrication (pore absorption), low cost, but low strength, porosity distribution needs to be controlled.
Application: Low speed, light load scenario (e.g., household appliance motors, automobile water pump bearing).
Copper-based oil-soaked bearings
Ingredient: Copper powder mixed with graphite, sintering, porosity 5%-15%.
Features: Better thermal conductivity is higher than iron-bearing, but the cost is higher, suitable for medium and highspeed and medium load applications.
Purpose: Office equipment (e.g., printers, photocopiers). Non-metallic materials
Polymer Materials
Typical materials: PTFE, PI, Nylon (PA).
Features: Self-lubricating, corrosion resistant, low noise, limited bearing capacity, refitted (e.g., glass fiber filler, molybdenum disulfide filler).
Uses: Food machinery, chemical equipment (such as stirring shaft bearings).
Ceramic Materials
Typical materials: Alumina (Al2O3), Silicon nitride (Si3N4).
Features: High temperature resistance, wear resistance, good insulation, but brittle, require to be used with metal bushings.
Application: High-temperature, high-speed applications (such as gas turbine bearings).
Carbon Graphite Materials
Ingredients: Natural or artificial graphite, possibly impregnated with resin or metals (e.g. antimony, copper).
Features: Self-lubricating, chemical-resistant, but low in strength and requires to be combined with metal backings.
Uses: Water lubrication bearing (e.g., ship stern shafts), chemical pump bearings.

Journal Bearing

4. Composites
Metal-Polymer Composites
Typical structure: Steelback + PTFE/PI sliding layer (e.g., Duroglide®, Rulon).
Features: Combined with the strength of metal and self-lubricating properties of polymer, suitable for medium and high speed applications.
Purpose: Automotive engine, compressor bearings.
Metal-Ceramic Composites
Typical structure: Steel back + ceramic coating (e.g. Al2O3, WC).
Features: High abrasion resistance, high temperature resistance, suitable for extreme environments.
Applications: Aerospace, energy equipment (e.g., wind turbine spindles).