NOVELTY - A thermoplastic material contains half-Heusler compound. The half-Heusler compound has silver-arsenic-magnesium type crystal structure and shift amount with respect to theoretical value of diffraction angle 2( theta ) of strongest line of plus minus 0.1 degrees . Valence electron number per atom of half-Heusler compound is 6. The half-Heusler compound contains nickel, palladium and/or platinum at 4c (1/4, 1/4, 1/4) site, bismuth at 4b (1/2, 1/2, 1/2) or 4a (0, 0, 0) site and rare earth element at 4b (1/2, 1/2, 1/2) or 4a (0, 0, 0) site.    USE - Thermoplastic material is used for thermoelectric generator such as seawater temperature thermoelectric generator and fossil fuel thermoelectric generator for solar power generation device, regeneration electric power generation device of factory exhaust heat and motor vehicle exhaust heat, optical detection device, field effect transistor and photomultiplier tube and for power supply for accurate temperature control apparatus such as cell of spectrophotometer, column of chromatography, constant temperature apparatus, cooling and heating apparatus, refrigerator and timepieces.    ADVANTAGE - The thermoplastic material has excellent oxidation resistance, stability and thermoelectric material and is economical and free from toxic elements.    DETAILED DESCRIPTION - A thermoplastic material contains half-Heusler compound. The half-Heusler compound has silver-arsenic-magnesium type crystal structure, valence electron number per atom of 6 and shift amount with respect to theoretical value of diffraction angle 2( theta ) of strongest line of plus minus 0.1 degrees . The half-Heusler compound contains nickel, palladium and/or platinum at 4c (1/4, 1/4, 1/4) site, bismuth at 4b (1/2, 1/2, 1/2) or 4a (0, 0, 0) site and rare earth element at 4b (1/2, 1/2, 1/2) or 4a (0, 0, 0) site. The half-Heusler compound has compositional formulae: RE(Ni1-x-yPdxPty)Bi (1), where RE is rare earth elements, x and y is 0-1, x+y is 1 or less and (1-x-y)x+xy+y(1-x-y) is more than zero, RE(Ni1-xPdx)Bi (2), where x is 0.4-1, RE(Ni0.5Pd0.5)Bi (3) or (RE1-uMu)((Ni1-x-yPdxPty)1-vMv)(Bi1-wM"w) (4), where M is zirconium having different valences, M is nickel, palladium, platinum or copper having different valences, M"is bismuth having different valences, u, v and w is 0-0.3 and u+v+w is more than zero. An INDEPENDENT CLAIM is included for manufacture of thermoplastic material. The nozzle used in manufacture of thermoplastic material is made from boron nitride.