The electrical pulse heating method makes it possi ble to measure the volume properties of a material (the resistivity, the enthalpy, and the specific heat). For the investigation, the impulse current heating facility described in [1] was applied. The specimen tempera ture was measured by the fast response pyrometer described in [2] and calibrated against the SI 10 300 temperature lamp. The zirconium nitride deposited, as the specular reflecting layer (2.5 µm), on the polished surfaces of the K 8 glass, 14 × 8 mm, 3.5 mm thick insulating substrates was investigated. The coating was produced at the All Russia Scientific Research Insti tute of Aviation Materials, by the magnetron sputter ing technique. The coating density estimated accord ing to the specimen mass growth was taken equal to 6.7 g/cm 3 . The composition of the deposited speci mens is presented in the table.To determine the composition, the EDAX energy dispersive spectrometer was applied; the measure ments were performed in the Quanta 600 FEG (FEI, the Netherlands) electronic microscope chamber. The X ray phase analysis (Bruker D8 Discover A25 DaVinsi Design diffractometer) showed that the coat ing consisted of zirconium nitride. The coating surface microstructure and thickness were determined by the scanning electronic microscopy technique. Figure 1a shows that the coating surface is composed of angular aggregates, ~200-500 nm in diameter. The linear dimensions of the aggregate particles are mainly ~15-60 nm. The slitlike interaggregate boundaries are dis tinctly pronounced. Figure 1b shows the results of measurements of the coating thickness in several points. The thickness instability in Fig. 1b might result from the preliminary diamond grinding of the side sur face that might cause a "spreading" of the actual size. The average coating thickness was equal to 2.6 µm.The investigation was carried out (1) on the flat speci mens immersed into water; (2) in the air, the flat spec imens pressed from above by an additional glass plate (the substrate); (3) on the specimens in the form of the blackbody model immersed into water.For more reliable measurements of the specimen temperature, the wedge shaped blackbody model was applied. It consisted of two substrates glued along the 14 mm edge in the form of a ≈14° dihedral angle with the deposited layers facing inside the wedge. The blackbody model was clamped in the current feeding electrodes and tightened with screws through the insu lation plates.When calculating the temperature scale for the investigated specimen as the individual plane (both in water and with the glass pressed from above), we need to know the normal spectral emissivity of the speci men surface, ε n, λ , at the wavelength of 856 nm. The handbook [3] gives the value of 0.78 at 2287 K taken from [4]. Note that,in [4], this value was obtained for Abstract-The zirconium nitride specimens were obtained as a thin (2.5 μm) layer deposited on the insulat ing K 8 glass substrates by the magnetron sputtering technique. The impulse current heating perm...
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