Understanding Complex Tribofilms by Means of H₃BO₃-B₂O₃ Model Glasses.

Area of Science:

• Tribology
• Materials Science
• Surface Chemistry

Background:

• Boric oxides react with atmospheric moisture to form boric acid films, sparking interest in boron compound tribology.
• The growth kinetics and tribological behavior of boric acid films on boric oxide substrates under controlled humidity remain understudied.

Purpose of the Study:

• To investigate the tribological properties of boric acid-boric oxide glass systems aged under controlled relative humidity.
• To determine the failure mechanisms of boric acid films under high-pressure and high-temperature tribological conditions.

Main Methods:

• Tribological testing at room temperature and 100°C with a 15 N load in YUBASE 4 oil.
• Characterization using confocal Raman spectroscopy, environmental scanning electron microscopy, atomic force microscopy, and focused-ion-beam scanning electron microscopy.
• Analysis of transfer film composition using small-area X-ray photoelectron spectroscopy.

Main Results:

• The study details the growth kinetics and tribological performance of boric acid films on boric oxide substrates.
• Film failure under stress and heat was analyzed, identifying key factors influencing lubricious film removal.

Conclusions:

• The research provides insights into the formation, properties, and failure mechanisms of boric acid films, crucial for understanding boron-based lubrication.
• This work addresses a gap in the literature regarding the tribology of boric acid-boric oxide systems under controlled environmental conditions.