Papers by Keyword: Zirconium Nitride

Abstract: Two equations with discrepancies of solid-state displacement reactions between AlN and ZrO₂ were analysed by thermodynamic calculation, and its results were substantiated by experiment. Results of thermodynamic calculation showed that the reaction equation of Bayer and Mocellin proposing could occured at 1411.26K, and it accord with TG-DTA and SEM analysis results, i.e. the reaction equation of Bayer and Mocellin proposing was true.

Abstract: The various nitrogen gas (N₂) flows for depositing zirconium-nitride (ZrN) films on the substrate of a p-type (100) silicon wafer are investigated through reactive magnetron sputtering by a pulsed-DC power. The results, based on the design of experimental (DOE) method, indicate that the deposition effect of the ZrN_x film is obviously affected by various flow rates of nitrogen gas at the specific pulsing duty cycles. The crystal orientation of the zirconium-nitride film has a less order microstructure which is similar to an amorphous microstructure. Although the composition ratio of chemical elements is not identical in Zr and N, the surface roughness, grain size, and resistivity are the better feature. The deposition rate is inversely proportional to the nitrogen flow rate and the chamber pressure is also an important factor. The basic effect of N₂ flow rate on the surface roughness is rougher when more nitrogen gas is supplied. The resistivity of ZrN_x thin film has a positive relationship to N₂ flow rates at the reactive vacuum chamber.

Abstract: Zirconium nitrides (ZrN) coatings have shown better quality in comparison to titanium nitrides (TiN) ones regarding the application in the mechanical processing of aluminum and titanium alloys. This work presents the results from investigation on properties of ZrN-based coatings intended for industrial application. The ZrN and ZrTiN hard coatings in a thickness of (3 5) m were obtained on stainless steel substrates by cathodic arc evaporation method. The coating hardness in the range of 25-32 GPa was evaluated using the Vickers measurement technique. The coating properties were studied in relation to the surface morphology by Atomic force microscopy (AFM) and Scanning electron microscopy (SEM). The analyses showed that the number and size of the macroparticles decrease when N2 pressure increases in the deposition chamber. X-ray diffraction analysis (XRD) was performed to identify the crystallographic structure, preferred orientation and stress of the ZrN coatings.

Abstract: The high-temperature oxidation behavior of WC-ZrN superhard nanocomposite film was studied in air between 500 and 700oC. The WC-ZrN film displayed poor high-temperature oxidation resistance, because of the formation of the nonprotective W-oxide scale and the less-protective, nonstoichiometric ZrO2-x oxide scale. The scale was prone to cracking and spallation. During oxidation, C and N escaped from the film into the air, while oxygen from the air diffused into the film.

Abstract: We investigated grain boundary crystallization of gas-pressure-sintered silicon nitride with zirconia and magnesia as sintering aids. Cation compositions were mostly uniform throughout the specimen however, ZrO2 was crystallized in the surface region, while ZrN in the inside. When the specimen was heat-treated at 1 atm nitrogen atmosphere, ZrO2 in the surface region transformed to ZrN. The transformation, however, was suppressed when alumina was incorporated as an additional sintering aid. Based on these results, we propose a model describing the reaction among Si3N4, SiO2, ZrO2, ZrN and N2. Observed microstructures and measured mechanical properties were consistent with the model.