Temporary enamel coatings for oxidation protection of Ti–6Al–4V at its hot working temperature of 1200 °C

• Published in: Journal of alloys and compounds Vol. 815; p. 152295
• Main Authors: Yu, Zheng, Feng, Min, Chen, Minghui, Shen, Changbin, Zhu, Shenglong, Wang, Fuhui
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 30.01.2020; Elsevier BV
• Subjects: Aluminum oxide; Coating materials; Diffusion coating; Enamel; Hardening; Hot working; Interface stability; Kaolin; Microstructure; Oxidation; Oxidation resistance; Oxygen; Particulate composites; Protective coatings; Quartz; Scanning electron microscopy; SEM; Titanium base alloys; Scanning electron microscopy; Oxidation; SEM; Coating materials; Microstructure
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2019.152295

Oxidation protection of temporary enamel coatings with or without additions of quartz and kaolin on Ti–6Al–4V alloy at its hot working temperature of 1200 °C was studied. After exposure for 5 h, the bare alloy has suffered from oxidation and sever oxygen ingression that gives rise to a deep hardening layer of 2250 μm. Enamel coating improves largely its oxidation resistance. An alloy/Ti5Si3/Al2O3/enamel layered structure forms at interface, which accompanies with the enamel coating retarding oxygen ingression. With addition of quartz and kaolin particles, the enamel composite coating is more effective in prohibiting the inward diffusion of oxygen than the pure enamel one. The incorporated ceramic particles are able to enhance viscosity of enamel, thus reducing diffusivity of oxygen through it while increasing the stability of the interfacial layered structure. [Display omitted] •Temporary enamel coatings are prepared on Ti6Al4V alloy for oxidation protection.•Oxygen ingress gives rise to a deep hardening layer of the titanium alloy.•Enamel coating prohibits oxygen invasion and reduces thickness of hardening layer.•An alloy/Ti5Si3/Al2O3/enamel layered structure forms at interface.•Adding kaolin and quartz particles enhances protectiveness of the enamel coating.