The PVD method starts late, develops fast, and has a low temperature (about 300~500 °C). The advantages are many, but the coating uniformity is not as good as the CVD method. The coating and the substrate are not firmly bonded, the coating hardness is relatively low, and the coating superiority is not. Fully reflected. The PVD process requires higher process than the CVD process, the equipment is more complex, and the coating cycle is long. At present, the commonly used PVD methods include low pressure electron beam evaporation (LVEE), cathode electron arc deposition (CAD), triode high voltage electron beam evaporation (THVEE), unbalanced magnetron sputtering (UMS), and ion beam assisted deposition ( IAD) Dynamics ion beam mixing (DIM), which differs mainly from the deposition material vaporization method and the plasma generation method, so that the film formation speed film quality is different.

2 coating tool development direction

1) New coating materials

There are many new types of tool coating materials: TiCN-based new coatings and TiCTiN coatings have good toughness and hardness, which is 2 to 4 times more durable than conventional TiN tools. In addition, new coating materials such as (Ti, Zr)CN, (Ti, Al)CN, (Ti, Si)CN, etc., which are based on TiCN, have appeared. AlON coated tools produce minimal crater wear. TiAlN has high temperature hardness and excellent oxidation resistance. It has high hardness and good oxidation resistance. Its cutting performance is better than TiN coating. The tool life can be increased by 1~4 times when it is used to process aerospace alloy materials. The CrCCrN coating has no titanium coating and can effectively cut titanium, titanium and other soft materials such as aluminum alloy. In addition, Hf, Zr, Ta carbide and nitride, Hf, Zr, Ti, N, Ta boride, Hf, Zr, Ti, Be oxide and other coating materials have been successfully used.

It is worth mentioning the diamond-like carbon coating of Multi-ScientificCoating in the United States. After depositing carbon onto the tool surface by hot cathode evaporation technology, the diamond-like carbon coating matrix is ​​well combined, with many diamond similar properties, high wear resistance and low friction coefficient. . Other ZrN, TiZrN diamond-like film coatings (DLC) applications are also expanding, mainly for the processing of non-ferrous alloys.

The titanium aluminum nitride coating is also converted from Ti0.75Al0.25N to Ti0.5Al0.5N. The oxidation temperature of Ti0.5Al0.5N coating is 700 °C, and an amorphous layer is formed on the surface by air heating. The Al2O3 film protects the coating.

Japan's Fujitsu has developed a new coating called SG, which consists of three layers of TiN, TiCN and Ti film. Its wear resistance is better than that of TiN coating, and the coating has high bonding strength with the substrate. The surface layer is Ti-based. The film layer has excellent heat resistance.

Switzerland has also developed a new process called “MOVIC” soft coating, which is coated with a solid lubricating film molybdenum disulfide on the surface of the tool. The cutting life of the tool is increased several times and an excellent machined surface can be obtained. Other chalcogen elements such as soft coatings such as WS2 have also made some progress. These soft coatings have good application prospects in processing high-strength aluminum alloy precious metals.

In recent years, high hardness coatings have begun to appear. Including cubic boron nitride (CBN) coating, carbon nitride (CNX), polycrystalline nitride superlattice coating, and the like. CBN coating hardness of 5200kgf / mm2, second only to diamond, can effectively cut other hard-to-machined alloys of hardened steel. If a carbon nitride (CNX) coating is capable of forming b-C3N4, it is theoretically possible to calculate that the hardness will exceed that of diamond. There have been reports of carbon nitride synthesis. Polycrystalline Nitride Superlattice Coating is a promising new tool coating. The hardness of polycrystalline TiN/NbNTiN/VN superlattice coating is 5200kgf/mm25600kgf/mm2, respectively. The superlattice coating is due to layer or layer. Difficulty in dislocations leads to high hardness.

2) Coating process

With the development of coating technology, a comprehensive PVDCVDPACVD method has emerged. In addition, there is an ion beam sputtering method. The ion beam assisted deposition technique (IBAD) can also be used for coating. The ion beam assisted deposition combines the advantages of vapor deposition and ion implantation. . Plasma-assisted chemical vapor deposition (PCVD) uses plasma to promote chemical reactions, which can reduce the deposition temperature to 200-500 °C. The Sol-Gel method has received more and more attention because of its own advantages.

MT-CVD (Warm Chemical Vapor Deposition) overcomes the shortcomings of general HD-CVD (high temperature chemical vapor deposition) to a certain extent, its deposition temperature is low (700 ~ 900 ° C), deposition speed is fast, coating thickness is thick, process ring plating Well, for the complex workpiece with uniform coating, and the coating adhesion is high, the residual stress inside the coating is small, which is better than the HT-CVD coating process.

The range of substrates used for coatings has also expanded, including high speed steels and hard alloy ceramics. In recent years, ceramic coated cemented carbide tools have developed rapidly. In particular, Al2O3 ceramics are particularly suitable for high-speed cutting due to their high chemical stability and oxidation resistance. Ceramic coatings account for a large proportion.

Although the tool coating process has achieved considerable development and special gradient coating processes, overall coating technology needs to be further improved.

3 conclusions

The coated tool better solves the contradiction between the strength and toughness of the tool and greatly improves the cutting speed of the tool durability. However, the coating is easy to peel off, and the process is complicated and expensive. Tool coating materials use up to TiC, TiN, Al2O3, diamond and composite coatings. Common coating method CVD method PVD method.

New coating materials and new coating methods continue to emerge. Special new high-hard coatings and soft-coating materials will make coating tools more and more widely used.

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Hydraulic Tool

A hydraulic tool is a type of tool that uses hydraulic power to perform various tasks. It operates by using fluid pressure to generate force and perform work. The hydraulic power is typically generated by a Hydraulic Pump, which pushes hydraulic fluid through a series of hoses and into the tool.
Hydraulic tools are commonly used in industries such as construction, automotive, and manufacturing. They are known for their ability to provide high levels of force and precision. Some common types of hydraulic tools include hydraulic jacks, hydraulic presses, hydraulic cutters, hydraulic crimpers, and hydraulic torque wrenches.
One of the advantages of hydraulic tools is their ability to generate a large amount of force with relatively small input effort. They can also be operated remotely, allowing for increased safety and convenience. Additionally, hydraulic tools are known for their durability and long lifespan.
However, hydraulic tools require regular maintenance, including checking and replacing hydraulic fluid, as well as inspecting hoses and fittings for any signs of wear or damage. It is also important to follow proper safety procedures when operating hydraulic tools, as they can be powerful and potentially dangerous if used incorrectly.

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