The Preparation Of High Temperature Oxidation-resistant Coating On TB2Alloys

When titanium is used at temperature above600℃, the applicationperformance will be greatly reduced by the surface oxidation and oxygen crispconstrains and other reasons. In this paper, Al deposition using metal source plasmaassisted magnetron sputtering deposition on the TB2substrate surface preparationTiAl coating, and then an F ion implantation experiments to further improve thehigh temperature oxidation resistance coating, the TB2substrate can be carried outon effective protection.In this experiment we use the DC magnetron method to prepare the coating.The high-temperature oxidation experiment results show that the TB2substrateoxidation weight gain is9.7mg/cm²after isothermal oxidation for60h, with thesevere instability happens. The oxide film is divided into two sections, the outerstructure is loose and uneven thickness with the oxide film flaks, while the innerlayer is dense. The oxidation weight gain of Ti-45Al coating is7.8mg/cm²andwithout the spalling of the oxide film. The surface of the oxide film is covered bythe TiO₂and Al₂O₃, while the TiO₂is majority and its structure is relatively loose.There are some holes and voids. The thickness of oxide film is about27um and itscross-section is divided into three layers: the outermost layer is TiO₂, mixed with asmall amount of Al₂O₃, the middle layer is Al₂O₃, while the innermost layer is mixedwith TiO₂and Al₂O₃. The oxidation weight gain of the coating samples with F ionimplantation1.5h is5.8mg/cm², the entire surface of the oxide film is relativelydense. The oxide film composition is still a mixture of TiO₂and Al₂O₃by the Alcontent and the phase component of the coating itself, but the relative content ofTiO₂and Al₂O₃is different. The thickness of oxide film is approximately21um, thesectional structure and composition of the coating is nearly the same with thecoating sample without F ion implanting. The oxidation weight gain of the coatingsamples with F ion implantation3h is5.1mg/cm². The surface structure of oxidefilm is more compact, while the voids and porosity reduces. The composition ofAl₂O₃content in the oxide film increases, while the TiO₂has decreased. The oxidefilm thickness is18um, the sectional structure and composition of the coating isnearly the same with the coating sample with F ion implantation for3h. Thediffusion exists between the substrate and these three coating samples.The metal source Al deposition is assisted to prepare the TiAl coating. Weselect the magnetron sputtering TiAl for15min and Al deposition for15min as acycle. The coating making by this method will neither appearances the stratification nor exists the surface cracks because of the high Al content. Alter twelve groups ofcycles we get the TiAl coating. The main components phase of the coating is TiAland TiAl₃with a small amount of Ti₃Al phase. The coating surface is relative roughwith a granular material of varying sizes. The surface spectroscopy analysis showedthat the composition phase of the coating is Ti-55Al. The oxidation weight gain ofthe coating is3.9mg/cm², after the isothermal oxidation for60h at800℃. While theoxidation weight gain of the coating with F ion implantation for3h is3.1mg/cm²,which improves the oxidation resistance of the coating to some extent. There aresome holes and pores on the surface of the oxidized coating samples, which mainlycontain the gray block Al₂O₃and the strip block mixed Al₂O₃and TiO₂. The crosssection of the oxide film is divided into two layers. The outer layer is Al₂O₃with theuneven thickness, while the inner layer is TiO₂. There is a layer of Al₂O₃formed onthe surface of the coating with F ion implantation, which is more compact anduniform. Therefore improves the oxidation resistance of the coating.