2015-Sustainable Industrial Processing Summit
SIPS 2015 Volume 7: Ionic Liquids & Energy Production
| Editors: | Kongoli F, Gaune-Escard M, Mauntz M, Rubinstein J, Dodds H.L. |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2015 |
| Pages: | 310 pages |
| ISBN: | 978-1-987820-30-0 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
< CD shopping page
Formation of Hard Metal Borides via Novel Molten Salt Electrolysis
Guldem Kartal Sireli1; Servet Timur2;1ISTANBUL TECHNICAL UNIVERSITY (ITU), istanbul, Turkey; 2ISTANBUL TECHNICAL UNIVERSITY, Istanbul, Turkey;
Type of Paper: Regular
Id Paper: 391
Topic: 13
Abstract:
The necessity of hard and corrosion-resistant surfaces on engineering components becomes progressively more vital to provide longer service life with better performance. Transition metal borides, an important subgroup of advanced ceramics, are the perfect candidate for various applications due to their extraordinary properties; i.e., high melting points and extreme hardness along with good wear resistance and fair corrosion resistance as well as excellent thermal and electrical properties. <br />Boriding, a thermal boron diffusion process, is one of the common surface modification technique to form metal borides MeB, MeB2, etc. (Me= metal) on the surface of metallic workpieces. Among several boriding processes, pack and paste boriding are found conventional applications due to their simplicity. However, these processes have many disadvantages, such as expensive powder usage, long process durations and solid waste generations. All these negative sides of currently used boriding techniques make boriding economically and environmentally very costly and hence hinder its widespread application. As an alternative, in this study, a new boriding method called CRTD-Bor (Cathodic Reduction and Thermal Diffusion based boriding) was applied to different metals and their alloys, namely Inconel 600, titanium, Ti6Al4V, TiNi and steels (AISI 1018 low alloyed, 440 martensitic stainless steel, and AISI 4140 alloy steel). The main benefit of this novel boriding technique is its ability to provide the high growth rate of boride layers in a short time. Besides, the environmental issues as experienced in the conventional boriding processes are also eliminated with the usage of a uniquely formulated electrolyte composition. Cross-sectional examinations along with thin film X-ray diffraction analyses confirmed the homogenously thick boride layer formations on different substrates. The grown boride layers improved the surface hardness of the alloys at least eight times; i.e., 2000HV, 3500HV, 1600 HV to 1900HV on Inconel, titanium, steels, respectively.