Improving resin-based composites by fabricating nanostructured Al2O3 -13wt% TiO2 coatings

Significance 

Recent technological advancement has seen increasing development of advanced materials. For instance, resin-based composites belonging to fiber-reinforced composites exhibit unique properties including high corrosion and high specific strength thus it is highly used in the automobile and aviation industries. This has attracted the attention of many researchers. Unfortunately, resin-based composites are highly affected by erosion and wear at elevated temperatures as compared to their metal counterparts due to lower softening hardness and temperature. To this note, mechanisms aimed at improving their wear properties are highly required.

Presently, ceramic coatings like aluminum oxide have been deposited onto metal surfaces to improve their tribological properties. Consequently, the same has been extended to polymer-based materials to improve their thermal and electrical owing to their low density as compared to metallic materials. However, metal layers have poor wear resistance as compared to ceramic coatings. Therefore, there is a great need to explored deeply the nanostructured oxide ceramic coatings for use on resin-based composites.

Recently, Harbin Institute of Technology scientists such as Zhiwei Zou and Feifei Zhou* led by professor You Wang successfully fabricated nanostructured Al2O3-13wt% TiO2 coatings onto the surface of the resin-based composite by atmospheric plasma spraying (APS). They systematically investigated the tribological and mechanical properties of the materials using various techniques like the scanning electron microscopy. Their research work is currently published in the research journal, Applied Surface Science.

In their study, the authors observed that the mechanical bonding strength and hardness increased at first before dropping as the temperature increased to reach the optimization point at a spraying current of 650A. In addition, the coatings produced a maximum wear resistance at a spraying current ranging from 600A to 650A. Furthermore, during the steady wear stage, the coefficient of friction of the coatings remained at 0.2.

The research team also found that the nanostructured oxide ceramic coatings were successfully fabricated on the resin-based composites surfaces. The bi-mode structure was derived from the nature of the melting during plasma spraying. For instance, fully melted powders resulted in fused structures while partially melted powders resulted in a three-dimensional net structure. As such, the net structures exhibited better nanomechanical properties including elastic modulus, hardness and elastic recoverability as compared to the fused structures.

On the other hand, among the various factors affecting the tribological properties of the coatings, the toughness was the most significant one. For instance, greater wear resistance was observed in coatings with greater toughness and fewer defects. Also, for partly melted bi-mode structures, an increase in the spraying current result in a corresponding decrease in the hardness of the coating. The Harbin Institute of Technology scientists are therefore optimistic that the study will help advance the design and fabrication of effective resin-based composites exhibiting unique properties to be used continuously in various industries.

Reference

Zou, Z., Wang, Y., Zhou, F.*, Wang, L., Liu, S., & Wang, Y. (2018). Tribological property of plasma-sprayed Al2O3-13wt%TiO2 coatings onto resin-based composites.  Applied Surface Science, 431, 75-80.

Go To Applied Surface Science

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