Technical ceramics from samarium monosulfide for the thermal explosion and magnetron methods of production of SmS films

Abstract

Physicotechnical foundations of producing technical ceramics from samarium monosulfide were developed. The stable daltonide-type compound SmS forms a solid solution primarily within the range of anion structural vacancies Sm_{1 + x}S_1–x[ ]_2x (x = 0–0.035) (1500°С). In the Sm–S–O system, the compound SmS is in equilibrium with the Sm3S4 and Sm2O2S phases. The surface layer of bulk samples and films of SmS contains the phases Sm3S, Sm2O2S, and xSm₂SO₄ · (1–x)Sm₂O₃. Samarium sulfide is thermally hydrolyzed (>300°C) and oxidized (>220°C) to form the Sm₃S₄ and Sm₂O₂S phases. In synthesizing samarium monosulfide from elements by an ampule method, addition of a 15–20% excess of metallic samarium to the initial mixture affords SmS in more than 95 mol % yield. The contents of the equilibrium impurities Sm₃S₄ and Sm₂O₂S are minimized. Technical ceramics based on SmS was obtained as sintered pellets 50 and 75 mm in diameter with a compressive strength of 45 MPa, a flexural strength of 1.6 MPa, and a density of 4.89 g/cm³. The rate of SmS film sputtering from a ceramic target on a NanoFab-100 platform under the optimal sputtering conditions (390 V, 150 W) was 1 Å/s. A SmS powder containing particles of 90–120 μm in size was used for thermal explosion spraying of semiconductor thermal sensors shaped as cubes with a side length of 5 and 10 mm.