The alloying of
titanium tube surface can also be called a kind of coating. Compared with the coating of palladium on
titanium, it has the advantages of strong binding force, wear resistance, corrosion resistance and so on. Compared with titanium palladium alloy, the surface content of palladium is high, the precious metal palladium is saved, the cost is reduced, and the performance is excellent.
Aluminizing on the surface of titanium tube can reduce the hydrogen absorption tendency of titanium. The best aluminizing condition is coating the titanium workpiece with 88% alumina, 4% aluminum fluoride and 8% aluminum powder. The temperature is 810℃. The thickness and structure of aluminized layer depend on the holding time. The coating with a thickness of about 2 mm can be obtained by using the encapsulation method for aluminizing in a short time, which has good bonding strength and does not affect the mechanical properties of the matrix. The coating consists mainly of titanium oxide phase, which forms a very effective barrier against hydrogen penetration.
After PD plating on titanium tube, Pd plating can be heated by different methods to spread the layer to the surface area of titanium tube, forming a titanium Pd alloying layer on the surface, so as to improve the corrosion resistance. Heating diffusion or laser surface remelting are both feasible in principle. The 150 micron palladium-plated film deposited in vacuum can be melted rapidly to form effective palladium alloy by irradiating the titanium surface with a laser.
