Ion nitriding (or glow discharge nitriding) was invented by the German B. Berghaus in 1932. The method is in a nitrogen-containing atmosphere of 0.1 to 10 Torr (Torr = 133.3 Pa), the furnace body is used as an anode, the workpiece to be treated is a cathode, and a direct current voltage of several hundred volts is added between the anode and the cathode, and ion permeation is performed. The nitrogen method (or glow discharge nitriding) was invented by the German B. Berghaus in 1932. The method is in a nitrogen-containing atmosphere of 0.1 to 10 Torr (Torr = 133.3 Pa), the furnace body is used as an anode, the workpiece to be treated is a cathode, and a direct current voltage of several hundred volts is added between the anode and the cathode due to a glow discharge phenomenon. A soft light like a neon light is applied to the surface of the workpiece being processed. At this time, the ionized gas component is accelerated by the electric field, and hits the surface of the workpiece to be heated. At the same time, nitriding treatment is performed by sputtering, ionization or the like.
The ion nitridation method is completely different from the conventional method of decomposing ammonia or using nitriding materials. As a new nitriding method, it has been widely used in automobiles, machinery, precision instruments, and extrusion molding. Machines, molds and many other fields, and its application range is still expanding.
The ion nitridation method has the following advantages:
1 Since the ion nitriding method does not rely on a chemical reaction, but uses an ionized nitrogen-containing gas to perform nitriding treatment, the working environment is very clean and there is no need for special equipment for preventing pollution. Thus, the ion nitridation method is also referred to as the "green" nitridation method of the 21st century.
2 Since the ion nitriding method utilizes the sputtering action of the ionized gas, the processing time can be remarkably shortened compared with the conventional nitriding treatment (the time of ion nitriding is only 1/1 of the ordinary gas nitriding time) 3 to 1/5).
3 Because the ion nitriding method directly heats the workpiece by glow discharge, no special heating and heat preservation equipment is needed, and a uniform temperature distribution can be obtained, and the heating efficiency can be improved by more than 2 times compared with the indirect heating method, thereby achieving energy saving effect. (Energy consumption is only 40 to 70% of gas nitriding).
4 Since ion nitriding is carried out in a vacuum, a non-oxidized processed surface can be obtained without impairing the surface finish of the workpiece to be processed. Moreover, since the processing is performed at a low temperature, the amount of deformation of the workpiece to be processed is extremely small, and it is not necessary to process it after the treatment, which is extremely suitable for the processing of the finished product.
5 By adjusting the ratio of nitrogen, hydrogen and other (such as carbon, oxygen, sulfur, etc.) atmosphere, the phase composition of the compound layer can be freely adjusted to obtain the desired mechanical properties.
6 ion nitriding can be nitrided from 380 ° C. In addition, special materials such as titanium can be nitrided at a high temperature of 850 ° C, so the range of adaptation is very wide.
7 Since ion nitriding is carried out by ion implantation at a low pressure, the gas consumption is extremely small (only a few percent of gas nitriding), and the processing cost can be greatly reduced.
Ion nitridation is carried out in dilute ammonia or a mixture of hydrogen and nitrogen. As with conventional gas nitriding, it is also possible to introduce a hydrocarbon gas into the gas mixture, which is the formation of ε-carbide in the white bright layer. These processes can also be controlled by decarburization of the surface layer to reduce the brittleness of the surface layer.
Http://news.chinawj.com.cn Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn
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