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The preparation process of titanium carbide-based cermet

wallpapers Industry 2020-11-05
There are many synthetic preparation processes for titanium carbide-based cermets, each with its advantages and disadvantages. In actual production, suitable methods can be selected according to different application requirements and price factors.

Here are a few brief introductions:
①Chemical vapor deposition (CVD)

This method is a process technology that deposits a concrete thin film coating on a substrate's surface using a space gas-phase chemical reaction. Because the entire responsibility of this method is based on thermodynamics, the CVD film has the advantages of good adhesion and coating ability, dense film layer, and high film base bonding strength, which can satisfy the realization of not limited to TiC such as TiN, TiCN, ISBN, And other single-layer and multi-layer composite coatings.

The disadvantage of this method is that the processing temperature is relatively high (generally 900~1200℃). The high temperature causes the steel matrix to soften. After processing, it needs to be vacuum quenched again. The process is more complicated, and the workpiece is also easy to deform, resulting in the matrix material's bending strength. Decrease; and harmful waste gas and waste liquid will be produced during the preparation process, which is easy to cause industrial pollution, which contradicts the country's green industry today, which also limits the comprehensive promotion and use of this law.

②Physical vapor deposition (PVD)

This method uses physical processes such as thermal evaporation, sputtering, glow discharge, and arc discharge to deposit the required coating on the substrate's surface, including evaporation coating, sputtering coating ion coating technology. The latter two are currently more commonly used PVD technologies for preparing ceramic coatings.

Compared with CVD, this method is a green thin film preparation technology, there is no environmental pollution problem, the processing temperature can also be lowered to 600 ℃, reducing the thermal impact on the workpiece, but as the temperature decreases, the bond strength of the deposited film will also be Lower than CVD film.

The PVD film usually has residual compressive stress, which is easy to crack and peel off due to brittleness. Also, it belongs to linear processing, which has low adhesion and coating properties. The workpiece needs to rotate or swing during processing, which increases the design difficulty and difficulty of the vacuum chamber—problems such as ineffective coating.

③Liquid deposition

This method is a wet chemical film forming method. The basic principle is to drive the metal compound's hydrolysis equilibrium movement through the ligand replacement between the ions in the solution. The metal oxide or hydroxide is deposited on the substrate to form a thin film coating. Since this method can be used for film deposition under low temperature/room temperature conditions, no heat treatment or expensive processing equipment is required during the preparation process. The operation is simple.

This method's disadvantage is that because it is essentially a reaction in an aqueous solution, the solution's concentration is inconsistent before and after the response during the deposition process. There are many influencing factors for the liquid phase reaction, and industrial stability is not high.

④ Thermal spraying

This method refers to heating a particular linear or powdered material to a molten or semi-melted state through a heat source such as flame, arc, or plasma. It accelerates the formation of high-speed droplets, which are sprayed to the substrate to form a coating on it. Strengthen or regenerate the material's surface performance, play a protective role, and restore the size of the parts caused by wear, corrosion, or processing tolerances. The method includes plasma spraying, arc spraying, and flame spraying techniques.

⑤In-situ synthesis method

The in-situ synthesis method is that the second phase in the material or the reinforcing phase in the composite material is generated during the formation of the material; that is, it is not present before the material is prepared but is generated in situ during the material preparation process; The two-phase reinforced particles are synthesized in situ, without pollution at the interface, and the second phase is evenly distributed, which can avoid the problems encountered in traditional powder metallurgy processes and smelting processes. With the development of in-situ composite technology, its application has been extended to metal-based and ceramic-based materials.

⑥Other synthetic methods

In addition to the above preparation processes, there are in-situ synthesis methods, fusion casting methods, powder metallurgy methods, mechanical alloying methods, thermal spraying, self-propagating high-temperature synthesis, high-density energy beam coating, sol-gel method, liquid EDM surface strengthening, and other synthetic methods of medium discharge. In actual industrial production applications, selecting the carbonized-based cermet composite material's preparation method can be determined according to its conditions and needs.

Trunnano is one of the world's largest producers of titanium carbide powder. If you have any questions or needs, please contact Dr. Leo by email: brad@ihpa.net.

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