Applications and advantages of silicon nitride ceramic cutting tools

Basic properties of silicon nitride ceramics

Physical Properties:

High Strength: Hot-pressed silicon nitride is one of the hardest materials in the world, with a hardness of 90-93 HRA.Low Density: With a theoretical density of only 3.19 g/cm³, it is significantly lighter than steel and engineering superheat-resistant alloys.

High Temperature Resistance: The decomposition temperature is 1800°C in air and reaches 1850°C in 110 MPa nitrogen.

Thermal Stability: It has a low coefficient of thermal expansion, high thermal conductivity, and excellent thermal shock resistance. It will not crack even after being immersed in cold water at 1000°C.

Chemical Properties:

Oxidation-resistant at high temperatures and resistant to thermal shock.

Intrinsically lubricated and with excellent wear resistance.

Strength may decrease with prolonged use above 1200°C; generally, operating temperatures should not exceed 1200°C.

Oxidation-resistant at high temperatures and resistant to thermal shock.

Intrinsically lubricated and with excellent wear resistance.

Strength may decrease with prolonged use above 1200°C; generally, operating temperatures should not exceed 1200°C.

As a representative of the third generation of ceramic cutting tools, silicon nitride ceramic cutting tools have demonstrated outstanding performance in a variety of industrial fields:

High-hardness material processing: Particularly suitable for machining hardened steel and cast iron up to HRC65.

Aerospace: Suitable for cutting difficult-to-machine materials such as titanium alloys and high-temperature alloys.

CNC machine tools: Meet high-speed cutting requirements and improve machining efficiency.

Special machining scenarios: Suitable for high-impact operations such as milling, planing, and interrupted cutting.

Notably, research on silicon nitride cutting tools began in my country in the 1970s. In recent years, through the addition of rare earth oxides, optimized sintering processes, and surface coating technologies, tool performance has continued to improve, gradually replacing traditional cutting tools in special material machining.

Compared with traditional carbide tools, silicon nitride ceramic tools have significant advantages, as shown in the table below:

It is particularly worth mentioning that silicon nitride ceramic cutting tools can achieve “turning and milling instead of grinding”, simplify the processing technology, save labor time, electricity and machine tool resources, and significantly improve production efficiency.

Performance Enhancement: Further enhance tool performance through optimized preparation processes and the introduction of new doping elements.

Expanded Applications: Demand in new energy vehicles, semiconductors, 5G communications, and other fields is expected to grow rapidly.

Process Innovation: Develop a diverse range of products (such as specialized tools for interrupted cutting and milling cutters) and new preparation technologies.

Cost Reduction: Improve cost-effectiveness through large-scale production and technological improvements.

With advances in science and technology and the development of new materials technologies, the application scope of silicon nitride ceramics will continue to expand. In the future, as material properties continue to improve and processing techniques advance, silicon nitride ceramics will demonstrate their superior performance in even more fields, becoming an indispensable and important material in the industrial sector.