Wear-resistant and electromagnetic absorbing behaviors of oleic acid post-modified ferrite-filled epoxy resin composite coating

• The post-modified Mn-Zn ferrite was prepared by grafting oleic acid on its surface to inhibit aggregation.
• The increasing in hydrophobicity and dispersion of modified coating improved compatibility between illers and polymer.
• The modified fillers can decrease the friction COF of the composite coatings resulting in the enhanced resistance to wear.
• The modified ferrite coatings are observed to exhibit better reflection loss compared with coatings with original ferrite.

The post-modified Mn–Zn ferrite was prepared by grafting oleic acid on the surface of Mn–Zn ferrite to inhibit magnetic nanoparticle aggregation. Fourier Transform Infrared (FT-IR) spectroscopy was used to characterize the particle surfaces. The friction and electromagnetic absorbing properties of a thin coating fabricated by dispersing ferrite into epoxy resin (EP) were investigated. The roughness of the coating and water contact angle were measured using the VEECO and water contact angle meter. Friction tests were conducted using a stainless-steel bearing ball and a Rockwell diamond tip, respectively. The complex permittivity and complex permeability of the composite coating were studied in the low frequency (10 MHz–1.5 GHz). Surface modified ferrites are found to improve magnetic particles dispersion in EP resulting in significant compatibility between inorganic and organic materials. Results also indicate that modified ferrite/EP coatings have a lower roughness average value and higher water contact angle than original ferrite/EP coatings. The enhanced tribological properties of the modified ferrite/EP coatings can be seen from the increased coefficient value. The composite coatings with modified ferrite are observed to exhibit better reflection loss compared with the coatings with original ferrite.