Sub-Nanometer Accuracy Combination Processing Technology for Nickel-Phosphorus Modified Surfaces Based on Aluminum...

Area of Science:

• Materials Science
• Optical Engineering
• Surface Metrology

Background:

• Metal mirrors often use Ni-P electroless coating after diamond turning.
• Polishing quality depends heavily on environment, medium, and force, with defects like scratches degrading surface roughness.

Purpose of the Study:

• To optimize magnetorheological figuring (MRF) fluid and process parameters for high-efficiency surface modification of Ni-P coated metal mirrors.
• To resolve scratch defects and improve surface roughness.
• To develop a high-performance metal mirror processing method.

Main Methods:

• Optimization of magnetorheological figuring (MRF) fluid and polishing parameters.
• Development of a small-head smoothing technique for high-efficiency, high-precision processing.
• Integration of ultrasonic cleaning for surface roughness improvement.

Main Results:

• Achieved surface roughness better than Ra = 0.39 nm.
• Ultrasonic cleaning effectively improved post-processing surface roughness.
• Processed a 370 mm parabolic mirror, reducing surface quality from RMS = 338.684 nm to RMS = 21.267 nm.

Conclusions:

• The developed MRF-based combined processing technology effectively resolves scratch defects and enhances surface quality of Ni-P coated metal mirrors.
• The method enables high-efficiency and high-precision surface modification for demanding optical applications.
• Significant improvements in mirror surface quality were demonstrated on a large-aperture parabolic mirror.