Influence of Laser Micro-Texturing and Plasma Treatment on Adhesive Bonding Properties of WC-Co Carbides with Steel

This article presents research on advanced surface preparation methods for sintered carbides (WC-Co, grade B2) commonly used in the tool industry, particularly in the context of bonding these materials with C45 steel using adhesives. Sintered carbides are widely used due to their high hardness, wear resistance, and good ductility, making them ideal for manufacturing tools operating in harsh conditions. Traditional bonding methods, such as brazing and welding, often result in stresses and cracks. Adhesive bonding has therefore emerged as an effective alternative to mitigate these challenges. The research focuses on comparing the results obtained through modern surface treatment techniques, such as laser micro-texturing and plasma treatment, with traditional methods like grinding, abrasive blasting, and electrolytic etching. The influence of these methods on adhesion properties and the strength of adhesive bonds was evaluated through mechanical tests, including static shear and pull-off tests. An approximately 50% increase in the mechanical strength of adhesive joints was observed for surfaces treated with low-temperature plasma (operating voltage: 18 kV, flow of gasses: 20 l/min., treatment time: 60 s) and laser micro-texturing (infrared fiber laser, wavelength: 1064 nm (±5 nm), power: 20 W), as compared to mechanical grinding. The shear strength of the adhesive joints was equal to 32 MPa and 30 MPa on average in the case of treatment with low-temperature plasma made of helium and argon, respectively. The highest strength of an adhesive joint was equal to 34.5 MPa on average in the case of laser micro-texturing.