The preparation process of titanium carbide-based cermet
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Author : TRUNNANO
Update time : 2020-12-08 08:42:52
Titanium carbide-based cermet is a heterogeneous composite material composed of metal or alloy TiC ceramic phase. It combines the high strength, high hardness, wear resistance, high-temperature resistance, oxidation resistance and chemical stability of ceramics. There are many synthetic preparation processes for titanium carbide-based cermets, each with its advantages and disadvantages. In actual production, suitable processes can be selected according to different application requirements and price factors.
1. Chemical Vapor Deposition (CVD)
This method is a process technology that deposits a solid thin film coating on the surface of a substrate by means of a space gas-phase chemical reaction. Because the entire reaction of this method is based on thermodynamics, the CVD film has the advantages of good adhesion and coatingability, dense film layer, and high film-base bonding strength, which can satisfy the realization of not limited to TiC such as TiN, TiCN, TiBN 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 bending strength of the matrix material. 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 green industry advocated by the country today, which also limits the comprehensive promotion and use of this law.
2. Physical vapor deposition (PVD)
This method uses physical processes such as thermal evaporation, sputtering, glow discharge, and arc discharge to deposit the desired coating on the surface of the substrate. Including evaporation coating, sputtering coating and ion coating technology. The latter two are currently more commonly used PVD technologies for preparing ceramic coatings.
The PVD film usually has residual compressive stress, which is easy to crack and peel off due to brittleness. In addition, it belongs to linear processing, which has poor 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.
3. Liquid deposition
This method is a wet chemical film forming method. The basic principle is to drive the hydrolysis equilibrium movement of the metal compound through the ligand replacement between the ions in the solution so that 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, and the operation is simple.
The disadvantage of this method is that because it is essentially a reaction in an aqueous solution, the concentration of the solution is inconsistent before and after the reaction during the deposition process, and there are many influencing factors for the liquid phase reaction, and the industrial stability is not high.
4. Thermal spraying
This method refers to heating a certain linear or powdered material to a molten or semi-melted state through a heat source such as flame, arc or plasma, and accelerates the formation of high-speed droplets, which are sprayed to the substrate to form a coating on it. Strengthen or regenerate the surface performance of the material, play a protective role, and can restore the size reduction of parts caused by wear, corrosion or processing tolerances. The method includes plasma spraying, arc spraying, and flame spraying techniques.
5. In-situ synthesis
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 reinforcement 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 and smelting processes. With the development of in-situ composite technology, its application has been extended to metal-based and ceramic-based materials.
6. Other synthetic methods
In addition to the above preparation processes, there are in-situ synthesis methods, melting and 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, the selection of the preparation method of the carbonized-based cermet composite material can be determined according to its own conditions and needs.
TRUNNANO (aka. Luoyang Tongrun Nano Technology Co. Ltd.) is a trusted global chemical material supplier & manufacturer with over 12 years’experience in providing super high-quality chemicals and Nanomaterials. The Titanium Carbide TiC Powder produced by our company has high purity, fine particle size. Please contact us if necessary.
