TiAlN: The titanium-aluminium-nitride coating
What advantages does the TiAlN coating offer compared to uncoated or TiN coated tools? In this article we describe the properties and advantages of the TiAlN coating.
General information about TiAlN coating
The titanium-aluminium-nitride coating (TiAlN), is an all-round coating and universally applicable. TiAlN is a chemical compound of the three elements titanium, aluminum, and nitrogen. The coating thickness is between 1-4 micrometers (μm).
The coating offers high resistance to heat and oxidation. This enables working with a higher cutting speed and thus accelerating working processes. Compared to uncoated tools, TiAlN coating, depending on the application, increase an up to ten times longer service life.
For which applications is TiAlN coating suitable?
The TiAlN coating is very well suitable for cutting hard materials like e.g. steel (N/mm²) <1,100 and stainless steel, as well as titanium alloys. As an all-round coating, it is also used for cutting aluminum, brass, bronze, and plastic.
In general, it should be noted that both the coating and the tool steel must be suitable for the application in hard materials. For example, an HSS twist drill with TiAlN coating can only be used to a limited extent in stainless steel, although the coating itself is intended for cutting hard materials of this type. In this case the coating is resistant to the high temperature of application, but the tool steel is not.
First signs of oxidation occur at a maximum application temperature of 800° Celcius (approx. 1,450° Fahrenheit).
Cooling is not mandatory. In general, however, cooling additionally increases the service life of the tool.
Comparison of TiN and TiAlN
| TiN | TiAlN | |
|---|---|---|
| Increase of service life (compared to uncoated tools) | three to four times longer | depending on application, up to ten times longer |
| Cutting speed | normal | high |
| Application | less hard materials (steel (N/mm²) <900) | hard materials (steel (N/mm²) <1,100, stainless steel) |
| Cooling | recommended | not mandatory |
| Nano hardness | 24 Gigapascal (GPa) | 35 Gigapascal (GPa) |
| Coat thickness | 1-7 μm | 1-4 μm |
| Coefficient of friction | 0,55 μ | 0,5 μ |
| Max. temperature | 600 °C | 800 °C |
As seen in the table, compared to TiN the TiAlN coating has better properties in all characteristics. The advantages of the TiAlN coating are reflected in the price: the same tool with the TiN coating is in general cheaper.
Summary
- All-round coating
- Depending on application, up to ten times longer service life
- High resistance to heat and oxidation
- High cutting speed
- Chemical compound of titanium, aluminum and nitrogen
- Nano hardness: up to 35 GPa
- Coat thickness: 1-4 μm
- Coefficient of friction: 0,5 μ
- Temperature: 800°C
- Application: steel (N/mm²) <1,100, stainless steel, titanium alloys, cast iron, aluminum, brass, bronze, and plastic
- Cooling not mandatory