Novel bamboo-based metal composites prepared with a high-efficiency thermal spraying method: a preliminary study

Bamboo is one of the green building materials that have been used for centuries. Combining with metal materials will endow bamboo with new functions, such as weather resistance, anti-corrosion, conductivity, and electromagnetic shielding. However, there is a natural barrier between bamboo and metal materials. This paper proposes fabrication of novel bamboo-based metal composites (BMC) which are composed of bamboo substrate and metal coating, without any adhesive, using an efficient and sustainable arc thermal spraying technique. In this method, the metal wire is melted and deposited on the bamboo substrate through a high-temperature heat source. In the feasibility experiment, arc spraying using aluminum as the wire electrode was selected. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) were used to observe and test the fabricated specimens. It was demonstrated that when the spraying voltage was 40 V, the deposition rate was as high as 5.8 g/min with the average thickness of the metal coating exceeding 400 μm. The surface of the BMC aluminum coating was flat, continuous, and compact with an average roughness of about Ra 3.0 μm. Based on experimental results, the integrity of bamboo substrate in thermal spraying was discussed. Results from SEM–EDS test showed that there are crack areas and adhesion areas between bamboo and metal coatings, and the highest bonding strength exhibited over 1.0 MPa. This work provides a new practice of fabricating novel BMC through a green manufacturing method with high efficiency. The findings of this study may be useful in understanding the preparation of BMC and can help find their suitability for a wide range of applications.