Types of sintered metal binders in diamond tools

Introduction

Diamond tools have revolutionized modern industries, particularly manufacturing and construction industries, with their remarkable mechanical and thermal characteristics. However, the diamond crystals require bonding to a metallic substrate in order to create a functional tool. Sintering of various metals to create metallic bonds with diamond crystals is a commonly used technique in the production of diamond tools. This paper will present an overview of different types of sintering metallic binders used in diamond tools, including copper, cobalt, iron, tungsten, silicon carbide, and brazing alloys. The characteristics, advantages, and disadvantages of each type of metallic binder will also be presented.

Copper-Based Binders

The copper-based binders are widely used in the production of diamond tools because of their low price and excellent thermal conductivity. The common copper-based binders used in the industry are copper-tin, copper-silver, and copper-phosphorus. Copper-tin binders are ideal for wet cutting applications where copper-silver and copper-phosphorus binders are suitable for dry cutting applications. Copper-based binders have good bonding strength with diamond crystals and are relatively easy to process. However, they have a relatively low melting point, which limits their usage in high-temperature applications.

Cobalt-Based Binders

Cobalt-based binders are commonly used in diamond tools because of their excellent wear resistance, high-temperature strength, and chemical stability. Cobalt is typically used as the base metal in the binders, with the addition of other elements, such as nickel, tungsten, and titanium, to improve the binder's properties. The resulting binder has a high bonding strength with diamond crystals, which makes it ideal for heavy-duty cutting and grinding applications. Cobalt-based binders' high melting point makes them ideal for applications where high temperatures are expected.

Iron-Based Binders

Iron-based binders are relatively inexpensive and have good bonding strength with diamond crystals, but their usage in diamond tools is limited because of their low wear resistance and poor high-temperature strength. They are commonly used in low-impact applications, such as drilling tools and saw blades. Iron-based binders typically contain other elements, such as nickel, cobalt, and copper, to improve their properties.

Tungsten-Based Binders

Tungsten-based binders have excellent high-temperature strength, wear resistance, and chemical stability, making them suitable for heavy-duty cutting and grinding applications. Tungsten carbide is typically used as the base metal, with the addition of cobalt or nickel to improve the binder's properties. Tungsten-based binders have high bonding strength with diamond crystals, but they are relatively brittle and can crack under high-impact loads.

Silicon Carbide Binders

Silicon carbide binders are commonly used in diamond tools because of their excellent thermal conductivity, wear resistance, and chemical stability. The silicon carbide binder is typically mixed with a metal binder, such as cobalt or nickel, to improve its bonding strength with diamond crystals. Silicon carbide binders have high resistance to thermal shock, making them ideal for high-temperature applications. They are also resistant to chemicals, such as acids and alkalis.

Brazing Alloy Binders

Brazing alloy binders are used in diamond tools to create a metallic bond between diamond crystals and a metallic substrate. The brazing alloys are typically made of copper, silver, nickel, or gold, mixed with various other elements to improve their properties. Brazing alloys have a high melting point, making them ideal for high-temperature applications. They also have good wear resistance, chemical stability, and bonding strength with diamond crystals. Brazing alloys are relatively easy to process, but they are generally more expensive than other binders, limiting their usage in the industry.

Conclusion

In conclusion, the choice of metallic binder in diamond tools is critical, as it can significantly impact the tool's performance and lifespan. Copper-based binders are relatively inexpensive, but their low melting point limits their usage in high-temperature applications. Cobalt-based binders are ideal for heavy-duty cutting and grinding applications because of their wear resistance and high-temperature strength. Iron-based binders are suitable for low-impact applications, such as drilling tools and saw blades. Tungsten-based binders have excellent high-temperature strength and wear resistance but can be brittle under high-impact loads. Silicon carbide binders have excellent thermal conductivity and chemical stability, making them ideal for high-temperature applications. Brazing alloy binders have good wear resistance, bonding strength, and high-temperature strength, but they are generally more expensive. Therefore, it is essential to consider the required performance criteria of a diamond tool when selecting a metallic binder.