What are the common surface treatment methods for tungsten carbide cutting blades

Surface treatment methods for tungsten carbide cutting blades are crucial for enhancing tool performance and extending service life. Below is a detailed explanation of these surface treatment methods:

Coating
Coating involves covering the blade surface with one or more thin films to improve its performance. Common coating materials include titanium nitride (TiN), titanium carbonitride (TiCN), aluminum oxide (Al₂O₃), among others. These materials provide excellent wear resistance, corrosion resistance, and high-temperature performance. Coating can significantly increase the hardness and corrosion resistance of tungsten carbide blades, reduce friction and wear, and thus extend their service life. For instance, a titanium nitride coating can increase the tool's hardness to over 2000HV and enhance its wear resistance by 3-5 times.

Spraying
Spraying is a technique that involves applying a coating to the blade surface using a spray gun. Methods such as high-velocity oxygen fuel (HVOF) spraying and plasma spraying are commonly used. HVOF spraying is suitable for workpieces with complex surfaces and thicker materials, while plasma spraying is ideal for thinner materials. Spraying can create a uniform and dense coating, improving the blade's wear and corrosion resistance. Blades with sprayed coatings can maintain stable cutting performance for a longer duration during processing.

Nitriding
Nitriding is a method that enhances the blade’s performance by forming a nitrided layer on its surface. The process typically involves high temperatures, where controlling the nitriding time and temperature can create a dense nitrided layer on the blade surface. Nitriding significantly improves the blade's hardness and wear resistance, making it more suitable for machining high-hardness materials. Nitrided blades can withstand greater cutting forces and thermal loads during processing.

Chemical Methods
Chemical methods involve forming a protective film on the blade surface through chemical reactions. Common chemical methods include electrolytic polishing and immersion techniques. Electrolytic polishing can remove burrs and oxides from the blade surface, enhancing surface smoothness, while immersion methods create a chemically modified layer on the blade surface, improving corrosion and wear resistance. Chemical methods can form a uniform and dense protective film on the blade surface, enhancing its corrosion and wear resistance, effectively extending the blade's service life.

Physical Methods
Physical methods use physical means to form a hardened layer on the blade surface. Common physical methods include polarization treatment and vacuum deposition. Polarization treatment involves applying an external electric field to rearrange atoms on the blade surface to form a hardened layer, while vacuum deposition uses chemical reactions to deposit a thin film on the blade surface. Physical methods can create a hard, wear-resistant protective layer on the blade surface, improving its hardness and wear resistance. This protective layer can effectively resist wear and corrosion during the cutting process, thereby extending the blade's service life.

In practical applications, these surface treatment methods can be used individually or in combination to achieve optimal tool performance and longevity. The choice of surface treatment method depends on specific application requirements, processing conditions, and cost considerations.