The interfacial microstructure of an Al-based coating on a Ti alloy surface has been designed by using phase diagrams and advanced first-principles calculations. Samples were characterized by x-ray diffractometry, scanning electron microscopy, optical microscopy, high resolution transmission electron microscopy and energy-dispersive spectrometry. The results show that the stability sequence of the Ti–Al intermetallics was Ti3Al > TiAl > TiAl2 > TiAl3. The TiAl3 transition layer with a strong self-healing property was obtained easily by metallurgical reaction of Al and Ti. The Al atoms in TiAl3 combined rapidly with the O atoms to form a new Al2O3 protective layer in air. This work provides theoretical support for the thermal processing of Ti alloys.
Gengzhe Shen,Liuyan Zhang,Huishu Wu,Zhiwei Gu,Shixuan Wang,Yuwen Liu,Qiongbin Zheng,Guibin Tan,Xiaohua Jie
Cold spraying aluminum-based coatings are widely used for corrosion protection of metals such as steel and magnesium alloy . However, poor pitting resistance and short protection life are the shackles of aluminum-based coating. In order to solve this problem, this paper innovatively utilized the synergistic effect of reduced graphene oxide (rGO) and layered double hydroxide (LDH) to modify the coating efficiently. Al-GLG coatings were prepared by cold spraying rGO and LDH-modified aluminum powders. The structure, composition and corrosion resistance of the Al-GLG coating were analyzed and compared with that of unmodified Al-based coating and graphene-modified Al-based (Al-G) coating. As a result, the Al-GLG coating presents a continuous network GLG surrounding the deformed aluminum powder, and this special coating exhibits pitting resistance and long life. The corrosion current density of the Al-GLG coating is only 0.01287 μA·cm −2 , which is three orders of magnitude lower than that of the Al-based coating, and its pitting potential is about −0.24 V SCE , which is over 540 mV higher than that of the Al-based coating. During the full immersion text, the Al-GLG coating keeps the largest Rc (7.21×10 4 Ω·cm 2 ) and low-frequency impedance modulus|Z| 0.01Hz (3.66×10 4 Ω·cm 2 ). The corrosion resistance mechanism of the Al-GLG coating was investigated via field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), Raman and X-ray photoelectron spectroscopy (XPS), respectively. The excellent pitting corrosion resistance of the Al-GLG coating is attributed to the synergistic effect of the shielding effect of reduced graphene oxide and the ion exchange inhibition effect of LDH.
危险品化学品经营许可证（带存储）