Surface Ceramics-Plasma Spraying and Self-propagating High Temperature Synthesis

plasma spraying is to generate a DC arc between the cathode and the anode. The arc ionizes the working gas into a high-temperature plasma. The formed plasma flame melts the powder to form droplets. After the high-speed airflow atomizes the droplets, it is sprayed to the substrate. Surface to form a coating. The advantage of plasma spraying is that its spraying temperature is very high, the center temperature can reach more than 10 000 K, can prepare any high melting point ceramic coating, and the coating density is good, the bonding strength is also very high; the disadvantage is that the spraying efficiency is low, and the equipment is expensive, the one-time investment cost is high.

self-propagating high-temperature synthesis (SHS) is a technology that uses the self-conduction of high chemical reaction heat between reactants to synthesize new materials. It has the advantages of simple equipment, simple process, high production efficiency, low energy consumption and no pollution. It is a surface engineering technology that is very suitable for the protection of the inner wall of pipelines. BySHShas the characteristics of high bonding strength, high hardness, corrosion resistance, etc., which can effectively prolong the life of the pipeline. The main components of ceramic linings commonly used in oil pipelines areFe Al₂O₃, the process is to evenly mix iron oxide powder and aluminum powder in the steel pipe in proportion, then rotate at a high speed on the centrifuge, and then ignite by electric spark. The powder will undergo a replacement reaction during combustion to formFe Al₂O₃ molten layer, the molten layer is delaminated under centrifugal force,Feis close to the inner wall of the steel pipe,Al₂O₃away from the pipe wall to form a ceramic lining.