Study On Corrosion Resistance Of Non-hydrogen Carburizing On Titanium Surface Layer

Titanium is widely used in the field of aerospace, petrochemical, biomedical science, Ocean Engineering, and other fields due to its small weight and high strength ratio, excellent corrosion resistance. However, Titanium has poor hardness and wear resistance, meanwhile it poor corrosion resistance in non-oxidizing acids such as HCl and H2SO4will Prone to general corrosion. What we expect results are increasing the strength of titanium and titanium alloys surface at the same time improving the corrosion resistance of titanium and titanium alloys. Timet invention a titanium matrix material for carbon alloying technology, the alloy showed excellent corrosion resistance in HC1solution. But the TiC layer Brittleness by this technical preparation and not conducive to actual use. In this paper, by the double glow plasma metallurgy technology to penetrate C on the surface of titanium and formationed TiC alloy. Achieved to improve the Corrosion resistance of titanium at the same time improve the surface hardness.This paper by SEM, EDS, XRD, electrochemical curves, comprehensive corrosion at room temperature and so on, to detection hardness, structure, phase composition and corrosion performance of specimens non-hydrogen carburized. Come to the conclusions:1. Samples surface hardness significantly increases after non-hydrogen carburizing process. And the surface hardness of the sample gradually increase as the carbonization temperature increases, compared to pure titanium substrate hardness is about3-5times.2. Non-hydrogen carburizing layer has a clear interface with titanium substrate, the thickness of the layer as the carbonization temperature rises gradually increased, from a dozen microns to tens of microns. TiC layer also increases as the carburizing temperature increases.3. Electrochemical corrosion experiment showed that after non-hydrogen carburizing process of pure titanium sample’s corrosion performance has been significantly improved in the3.5%NaCl solution,5%HCl solution and10%H2SO4solution. Corrosion potential increases400-800mv, Victoria blunt current density is reduced from0.1～0.01mA/cm2to0.01mA/cm2, Indicates that the corrosion resistance of the carburized specimens is improved.4. The corrosion solution immersion test data at room temperature conditions in different concentrations of HCl and H2SO4showed that a substantial increase of corrosion resistance in reducing acid of titanium after hydrogen-free carburizing. When the HC1corrosion solution concentration is Less than20%. the corrosion rate of titanium specimens after carburizing is less than0.0062mm/a, Compared to titanium corrosion rate of the sample (3.6957mm/a) reduced590times; When the concentration of H2SO4solution is Less than60%, the corrosion rate of titanium specimens after carburizing is less than0.0020mm/a, Compared to titanium corrosion rate of the sample (3.6957mm/a) reduced340times.5. Hydrogen-free carburizing treatment to improve the corrosion resistance of titanium in HCl and H2SO4solution, while the surface hardness also improved.