The effects of diffusion barrier layers on the microstructural and electrical properties in CoSb3 thermoelectric modules

Ni/Ti/SKD/Ni (SKD: skutterudite) thermoelements were fabricated by spark plasma sintering and electroplating procedures. The interfacial stability was evaluated by long-term isothermal aging and multi-round thermal shock tests. The interfacial diffusion at Ni/SKD and Ni/Ti in the thermoelements during high temperature aging up to 15 days was systematically studied by scanning electron microscopy with elemental distribution. The growth kinetics of the intermetallic compounds was analyzed, and the coefficients of the intermetallic compound growth rate were calculated. For the Ni/SKD interface, there was no inter-diffusion at temperatures below 200 °C. However, three intermetallic compound layers for the Ti/Ni interface were confirmed to be TiNi3, TiNi and Ti2Ni sequentially from the Ni side to the Ti side at temperatures above 500 °C, leading to an interfacial structure of Ti/Ti2Ni/TiNi/TiNi3/Ni. All interfaces maintained good bonding strength after long-term isothermal aging and multi-round thermal shock tests. The experimental data demonstrated that Ni is an ideal candidate as the electrode of skutterudite thermoelements at both the hot and cold sides.

Interfacial structure and stability in Ni/SKD/Ti/Ni skutterudite thermoelements

Thermal durability of novel thermoelectric materials for waste heat recovery

The invention discloses an SPS connection method for tungsten and molybdenum dissimilar refractory metals. The SPS connection method is characterized in that blocky tungsten is taken as a base body, the base body and molybdenum powder are sintered and connected through an SPS technology, so that a connecting piece of the tungsten and molybdenum dissimilar refractory metal is obtained. According tothe SPS connection method, the molybdenum powder can be sintered and compacted on the tungsten base body, meanwhile, sintering connection of the tungsten and molybdenum metals is realized, so that the connecting piece with high strength and good forming effect is obtained, and the room temperature shearing strength of a joint can reach 152.9 MPa.

SPS connection method for tungsten and molybdenum dissimilar refractory metals

The invention relates to a middle-high temperature thermoelectric module. The middle-high temperature thermoelectric module comprises at least one group of thermoelectric pair, wherein the thermoelectric pair comprises two thermoelectric blocks connected through an insulating supporting plate; an electrode formed on a high temperature end surface of the thermoelectric pair; a diffusion blocking protection layer formed at least on the surface of the thermoelectric pair and/or the surfaces of the two thermoelectric blocks; an anti-oxidation layer formed at least on the surface of the thermoelectric pair and/or the surfaces of the two thermoelectric blocks; and an aerogel thermal insulation layer filling a gap of the at least one group of thermoelectric pair. The thermoelectric module provided by the invention simultaneously has the performance of sublimation prevention, anti-oxidation, heat insulation and the like, and the thermoelectric performance and the efficiency of the thermoelectric module are improved; in addition, the thermoelectric module has a self-protection function when working under conditions relating to corrosive gas, moist, chemical medium corrosion, temperature cold-hot alternation and the like.

Middle-high temperature thermoelectric module

The material of the electrode applies the molybdenum with the thickness of 0.5-1.5 mm. The electrode of cobalt antimonide base thermoelectric material achieves the combination, by introducing the titanium through the two-step procedure, the discharging and the sinter. The sinter of the cobalt antimonide thermoelectric material and the combination between the powder and the electrode material are processed simultaneously. The high intensity of combination, excellent stability and convenient combination technology are supplied.

Electrode material of cobalt base antimonide pyroelectric material and preparing process thereof

CoSb3 based materials are promising for power generation in the intermediate temperature range. In the present work, we have developed a novel technology for the fabrication of CoSb3 thermoelectric (TE) couple by spark plasma sintering (SPS). Molybdenum (Mo) was selected as the electrode material and a titanium (Ti) layer was inserted between Mo and CoSb3 to realize the joining of Mo to CoSb3 at a lower temperature. Shear tests showed that the joint possesses a shear strength ranging from 55 MPa to 70 MPa. The potential voltage measurement showed that the joint exhibits good electrical properties. All the results indicate that the Mo/Ti/CoSb3 joining technology is suitable for fabricating TE couples using the CoSb3 based materials.

Chen Lidong

Papers

Electrode material of cobalt base antimonide pyroelectric material and preparing process thereof

Mo / Ti / CoSb3 joining technology for CoSb3 based materials