Si-O-C amorphous coatings for high temperature protection of In0.4Co4Sb12 skutterudite for thermoelectric applications

Abstract

High temperature corrosion of thermoelectric materials is one of the most important issues linked with their application for power generation, especially in terrestrial conditions. The high chemical affinity of elements composing thermoelectric material to oxygen results in continuous degradation at high temperatures of most state-of-the-art materials. This issue is also well recognized in the case of antimonide skutterudites. The simplest way to protect against this process is the use of coatings. Complicated geometry of thermoelectric module favors coatings that can be deposited in a simple way on an assembled module. Such an opportunity, besides good thermal stability and appropriate thermal and electrical properties, is provided by amorphous silicon oxycarbide Si-O-C coatings. In this work, the results on Si-O-C coatings deposited on In0.4Co4Sb12 skutterudite are presented. The influence of heat treatment temperature and substrate roughness on the deposited layer is shown. Protective properties of the Si-O-C layer are presented by comparison of electrical conductivity and Seebeck coefficient of coated and uncoated samples, before and after isothermal oxidation in air at 430 °C for 24 h. In such conditions, the uncoated samples are distinctly oxidized (weight gain of 2.4%) with strongly affected electrical properties, while the coated samples show a slight weight gain of 0.1% and almost unchanged electrical properties.

Macromonomers as a Novel Way to Investigate and Tailor Silicon-Oxycarbide-Based Materials Obtained from Polymeric Preceramic Precursors

“…As both the free-carbon content and its type can vary, silicon-oxycarbide-based black glass can be a semiconductor or insulator, and the addition of carbon forms, for example, can make the material conductive [6]. Such properties make silicon oxycarbide a promising material for protective coatings [7,8], electrodes in batteries [9], fuel cells [10], catalysis [11,12], or in medicine [13,14].…”

“…Materials 2021, 14, x FOR PEER REVIEW 2 of 17 protective coatings [7,8], electrodes in batteries [9], fuel cells [10], catalysis [11,12], or in medicine [13,14]. The synthesis of silicon-oxycarbide-based black glass is impossible with standard powder methods.…”

PbO-SiO2 Based Glass Coating of PbI2 Doped PbTe

“…Airtight coating allow work to be carried out in the air atmosphere and use without heavy and expensive atmosphere tight encasing. Coating of thermoelectric materials have been suggested several times before using organic coating [9,10], ceramic coating [11], and aerogel casings [12]. However, such coatings tend to degrade at high temperature, crack, and are very expensive.…”

Current Research Status of Skutterudite-based Thermoelectric Materials and Modularization Techniques for Mid-high Temperature Applications

“…Electrical conductivity and Seebeck coefficient of uncoated and Si-O-C coated In0.4Co4Sb12 samples before and after 12 h oxidation at 430°C. [17] Fig . 11.…”