Creating Stronger GCFRP /Alloy Steel Joints for Manufacturing High‐Performance Sucker Rod Through Effective NaOH Anodizing and Simple Resin Pre‐Coat

ABSTRACT

In the sucker rod systems of the petroleum industry, achieving a robust and durable connection between glass‐carbon fiber reinforced polymer (GCFRP) and alloy steel remains a key challenge in constructing lightweight, corrosion‐resistant, and long‐lasting composite sucker rod structures. Fabricating high‐performance bonded joints heavily depends on the quality of the interface. This study combined anodic oxidation of alloy steel with resin pre‐coating (RPC), systematically investigating the influence of sodium hydroxide electrolyte concentration on the surface characteristics of the alloy steel and the bonding interface performance with GCFRP. The results showed that anodic oxidation with 15 wt% NaOH produced uniformly distributed, dense micro‐channels on the alloy steel surface, leading to significant improvements in surface roughness and wettability. This porous architecture provided ideal anchoring points for epoxy resin infiltration. Coupled with the RPC process, pore defects at the root of the micro‐channels were effectively eliminated, forming a continuous, full‐thickness reinforced structure with high‐strength mechanical interlocking. The treated GCFRP/alloy steel joint exhibited a bonding strength of 19.43 MPa, which represents a 37% improvement over untreated specimens. Furthermore, failure mode shifted from interfacial debonding to cohesive failure within the GCFRP substrate, indicating that the interfacial strength now exceeded the cohesive strength of the adhesive itself.