How Motors Achieve Low Outgassing in Vacuum Environments

Motors achieve low outgassing in vacuum environments primarily through material selection, manufacturing processes, and specialized designs aimed at reducing or capturing the release of internal gases. The following are key technologies and measures for implementing vacuum motors:

Material Selection: Low Outgassing Materials

Structural Materials: Use low-outgassing metals or inorganic materials such as stainless steel and ceramics, avoiding high-volatility materials like plastics and rubber.

Insulating Materials: Employ vacuum-grade insulating materials like polyimide and polytetrafluoroethylene (PTFE) to minimize the release of organic gases.

Lubricants: Use vacuum-compatible lubricants such as perfluoropolyether (PFPE) or molybdenum disulfide, avoiding the volatilization of traditional greases.

Adhesives and Sealants: Choose low-outgassing sealants like epoxy resins and silicones.

Manufacturing Processes: Reducing Contaminants

Cleaning Processes: Utilize ultrasonic cleaning and plasma cleaning to remove oils and particles.

Vacuum Baking: Perform high-temperature vacuum baking (e.g., 150–300°C) on components before assembly to pre-release gases.

Oxygen-Free Encapsulation: Assemble in an inert gas environment to reduce adsorbed gases.

Specialized Design: Isolating Gas Release

Sealed Design:

Fully Sealed Motors: Use metal welding or ceramic seals to completely isolate internal gases.

Vented Design: Utilize microporous structures for slow gas release, preventing sudden outgassing from affecting vacuum levels.

Internal Adsorption Design: Place getters (e.g., zirconium-aluminum alloy) inside the motor to actively adsorb residual gases.

Thermal Management Optimization: Heat dissipation is challenging in vacuum environments. Design effective thermal conduction paths (e.g., metal substrates) to prevent overheating and material outgassing.

Testing and Validation

Outgassing Rate Testing: Measure the motor's Total Mass Loss (TML) and Collected Volatile Condensable Materials (CVCM) using mass spectrometers.

Long-Term Vacuum Operation Testing: Simulate actual operating conditions to ensure motor stability in a vacuum.

Application Scenarios

Spacecraft: Attitude control motors, solar array drive motors.

Vacuum Equipment: Motors for semiconductor coating machines, particle accelerators, and vacuum pump drives.

Scientific Instruments: Precision adjustment motors for electron microscopes and space telescopes.

Challenges and Considerations

Lubrication Challenges: Lubricants can easily volatilize or solidify in a vacuum, necessitating space-grade lubrication solutions.

Heat Dissipation Limitations: The absence of convective cooling requires reliance on thermal conduction or radiation design.

High Costs: Low-outgassing materials and specialized processes increase manufacturing costs.

Through the comprehensive measures outlined above, motors can achieve low outgassing in vacuum environments, meeting the stringent requirements of high-vacuum systems for gas release and ensuring long-term, stable operation of equipment.