A sand erosion test system was set up. The relationship between gas pressure and sand particle velocity was obtained by using particle image velocimetry method

and the erosion performance of TC4 titanium alloy and TiN/Ti multilayer coating was tested at the condition of sand concentration 28.91g/m3

sand particle velocity 80m/s

and impact angle 30°. The results show that

the anti-erosion performance of TC4 titanium alloy is poor with average mass loss rate about 0.7mg/min. TiN/Ti multilayer coatings can withstand sand erosion more than 200 minutes. TiN/Ti multilayer coating with modulation ratio of 1:3 is superior to that with the modulation ratio of 1:1 on the anti-erosion performance. Micro-spalling caused by the vertical impact component of sand particle velocity is the main reason for erosion damage of coating. Therefore

the key to improve anti-erosion performance of multilayer coating is enhancing the toughness.