METHOD OF PRODUCING COMPOSITE BRANCH OF THERMOELEMENT OPERATING IN RANGE OF TEMPERATURES FROM ROOM TO 900 °C

摘要

FIELD: power engineering.;SUBSTANCE: invention relates to thermoelectric energy conversion and can be used during manufacturing of thermoelectric composite thermoelement branches, meant for making electric power generators with high coefficient of conversion. Proposed method of making composite thermoelement branches connection sections of low-, medium- and high-temperature thermoelectric materials includes preliminary application of metal coatings on ends of joined sections, selected from: nickel, indium, iron, molybdenum, tungsten, forming binding layer between sections, installation of all sections in series at increasing operating temperature of butt joint so, that between low and medium temperature sections, as well as between medium- and high-temperature sections binding layers are formed of layer stack Ni/In/N. Assembled mold is placed in plant of spark plasma sintering and heated to temperature of 450–460 °C. It is kept at this temperature for 5–8 minutes at pressure of 3–5 Mpa, in vacuum, until dissolution of boundary part of nickel in molten indium. Then it is cooled to room temperature and isothermal annealing is made in electric furnace with controlled temperature in atmosphere containing 97 % of argon and 3 % of hydrogen, at temperature of 420±2 °C at pressure of 0.5–1.0 MPa for 6–10 hours to produce high-temperature intermetallic compound Ni₂In₃. After diffusion welding process mold is gradually cooled to room temperature.;EFFECT: technical result is reliable and strong connection of sections of composite thermoelement branches.;6 cl, 2 dwg, 1 tbl