Plasma electrolytic oxidation of Titanium AluminidesShow others and affiliations
2016 (English)In: IOP Conference Series: Materials Science and Engineering, Institute of Physics Publishing (IOPP), 2016, Vol. 118, no 1, article id 012025Conference paper, Published paper (Refereed)
Abstract [en]
Due to their outstanding specific mechanical and high-temperature properties, titanium aluminides exhibit a high potential for lightweight components exposed to high temperatures. However, their application is limited through their low wear resistance and the increasing high-temperature oxidation starting from about 750 °C. By the use of oxide ceramic coatings, these constraints can be set aside and the possible applications of titanium aluminides can be extended. The plasma electrolytic oxidation (PEO) represents a process for the generation of oxide ceramic conversion coatings with high thickness. The current work aims at the clarification of different electrolyte components' influences on the oxide layer evolution on alloy TNM-B1 (Ti43.5Al4Nb1Mo0.1B) and the creation of compact and wear resistant coatings. Model experiments were applied using a ramp-wise increase of the anodic potential in order to show the influence of electrolyte components on the discharge initiation and the early stage of the oxide layer growth. The production of PEO layers with technically relevant thicknesses close to 100 μm was conducted in alkaline electrolytes with varying amounts of Na2SiO3•5H2O and K4P2O7 under symmetrically pulsed current conditions. Coating properties were evaluated with regard to morphology, chemical composition, hardness and wear resistance. The addition of phosphates and silicates leads to an increasing substrate passivation and the growth of compact oxide layers with higher thicknesses. Optimal electrolyte compositions for maximum coating hardness and thickness were identified by statistical analysis. Under these conditions, a homogeneous inner layer with low porosity can be achieved. The frictional wear behavior of the compact coating layer is superior to a hard anodized layer on aluminum.
Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2016. Vol. 118, no 1, article id 012025
Series
IOP Conference Series: Materials Science and Engineering, ISSN 1757-8981 ; Volume 118, Issue 1
Keywords [en]
Alkalinity, Aluminum coatings, Anodic oxidation, Ceramic coatings, Ceramic materials, Electric discharges, Electrolysis, Electrolytes, Hardness, High temperature effects, Oxides, Silicates, Thermooxidation, Titanium, Titanium oxides, Wear of materials, Wear resistance, Chemical compositions, Compact coating layers, Electrolyte compositions, Lightweight components, Oxide ceramic coating, Plasma electrolytic oxidation, Substrate passivation, Wear-resistant coating, Oxidation
National Category
Materials Engineering
Identifiers
URN: urn:nbn:se:hj:diva-51170DOI: 10.1088/1757-899X/118/1/012025ISI: 000376260700065Scopus ID: 2-s2.0-84971623101OAI: oai:DiVA.org:hj-51170DiVA, id: diva2:1507531
Conference
18th Chemnitz Seminar on Materials Engineering, 10 March 2016 through 11 March 2016
2020-12-082020-12-082020-12-08Bibliographically approved