No abstract available

[en] A series of interstitial ternary nitrides R₂Fe₁₇N_3-δ has been prepared via a gas-solid reaction for R=Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Y. These nitrides have structures related to the Th₂Zn₁₇ or Th₂Ni₁₇ structures of the R₂Fe₁₇ parent compounds, but the unit cell volumes are 6%--7% greater, and the Curie temperatures are approximately 400 K higher. The Fe-Fe exchange interactions are increased by a factor of 2.8 by nitrogenation, whereas the R-Fe exchange interactions are little changed. All compounds exhibit easy-plane anisotropy at room temperature, except for Sm₂Fe₁₇N_3-δ, which shows strong uniaxial anisotropy and may be used to make permanent magnets. The Er and Tm compounds exhibit spin reorientations below room temperature. The anisotropy due to the iron sublattices is easy plane (K₁ = -1.3 MJ/m³ at 4.2 K for Y₂Fe₁₇N₃), but it changes sign to easy axis with cobalt substitution (K₁ ∼ 1.0 MJ/m³ at 4.2 K for Y₂(Fe_1-xCo_x)₁₇N_3-δ when x≥0.2)

[en] This publication constitutes completion of the first phase in a program to update and upgrade the 1966 Databook, ''Engineering Properties of Ceramics'', (AFML-TR-66-52). The data are presented in the International System (SI) of units as well as in the engineering units used in the 1966 edition. Most data are referenced to the original source. Also, material and testing factors influencing each reported property are specified insofar as possible. The nitrides covered include these of alkaline earth metals, Al, B, Si, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, rare earths, U, Pu, and Th. 1373 references

[en] Electronic emission spectra of several diatomic metal nitrides were obtained using a microwave discharge source. A survey of metals applicable to the experimental method produced nitrides of zirconium, vanadium, niobium, tantalum, molybdenum, aluminum, and boron. The nature of the carriers has been confirmed by isotopic substitution. Results of the rotational analysis are listed for ZrN, TaN, NbN, VN, MoN, BN, AlN, and TiN. (DLC)

[en] The present work deals with the development of the model of interatomic interactions in nitrides, to the calculation of the parameters of the Mie-Grueneisen (MG) and the modified Morse (MM) potentials, to the calculation of p-V diagrams, and to comparing them with quantum mechanical calculations. A model of the interatomic interactions in cubic mononitrides is considered. The parameters of the Mie-Grueneisen potential and the modified, four-parameter Morse potential are determined. Calculated U-V and p-V dependence for ThN, UN, PuN, TiN, ZrN, HfN, VN, and CrN are given and compared to quantum mechanical calculations. Critical values of the pressure in the bulk that determine the ultimate strength under all-around tension and, correspondingly, the critical elastic deformation are established

[en] Single phase alloys of composition RFe₁₁Ti with R=Y, Sm, and Dy were prepared by induction melting. The samples were nitrided by thermal cycling to 770 K, at a heating rate of 10 K/min, under an atmosphere of nitrogen in a thermopiezic analyzer (TPA). For YFe₁₁TiN the x-ray diffraction (XRD) patterns give a=0.8611 nm and c=0.4802 nm for the tetragonal structure, space group I4/mmm. This represents a 3% volume expansion of the nitrogen-free unit cell. The amount of absorbed nitrogen corresponds to one nitrogen atom per formula unit indicating that RFe₁₁TiN is a true nitrogen compound with the nitrogen atoms occupying the 2b site in the structure. The expansion of the unit cell is accompanied by a dramatic increase in the Curie temperature for all compounds

[en] The cold cap floating on top of the molten glass pool in liquid fed joule-heated ceramic melter plays an important role for operation in the vitrification process. A series of such phenomena as evaporation, melting and thermal decomposition of HLLW (high-level liquid waste) takes place within the cold-cap. An understanding of the varied thermal decomposition behavior of many nitrates constituting of HLLW is necessary to elucidate a series of phenomena occurring through the cold-cap. In this study, the reaction rates of the thermal decomposition reaction of 13 kinds of nitrates including Na, Nd, Zr, Gd,Ce,Cs, Fe, La, Mn, Ba, Pr, Pd and Sr, which are main constituents of simulated HLLW, were investigated using thermogravimetric instrument in a range of room temperature to 1000 Celsius degrees. The reaction rates of the thermal decompositions of 13 kinds of nitrates were depicted according to composition ratio (wt%) of each nitrate in simulated HLLW (sHLLW). It was found that the thermal decomposition of sHLLW was able to be predicted by the reaction rates and reaction temperatures for the individual nitrates. The thermal decomposition of sHLLW with borosilicate glass system was also investigated. It was observed that the thermal decomposition of alkali metal and alkaline-earth metal nitrates were affected by the borosilicate glass. For other nitrates such as lanthanides, zirconium nitrate, iron nitrate and so on, the effects of their thermal decomposition in the presence of borosilicate glass were not observed. The above results will be able to provide a useful knowledge for understanding the phenomena occurring through the cold-cap

[en] It is proposed to use the multiperiod binanolayer composites (TiAlSi)N/MeN (Me-Zr, Nb, Cr, Mo) for controlling the structure, stress state and mechanical properties of a multi-element nitride (TiAlSi)N. The deposition of the layers was carried out by the method of vacuum-arc evaporation at different bias potentials on the substrate U_b = -110 and -200 V. It has been determined that mononitrides with a high Me-N binding energy in the binanolayer composite determine the crystallite growth in thin (nanometer) layers. The growth texture is formed in composites containing mononitrides based on transition metals with a relatively small atomic mass (Cr, Mo) at U_b = -110 V. The growth texture is formed at a larger U_b = -200 V when dealing with mononitride based on heavy metal (Zr). The greatest hardness is achieved in textured materials deposited at U_b = -200 V. This is typical both for a monolayer multi-element nitride (TiAlSi)N (hardness is 42.5 GPa) and for multiperiod nanolayer composites based on it (the highest hardness is 47.9 GPa for a composite (TiAlSi)N/ZrN).

No abstract available

[en] It has been shown that Fe-N/Si-N multilayer films has excellent soft magnetic properties, but their properties are deteriorated easily by increasing the temperature above 400 degree C.¹ In this study, we added a small amount of Zr and Ta to the Fe-N layer to improve their thermal stability of the soft magnetic properties. Multilayer films about 3000 A thick were deposited by an opposed target sputtering apparatus on glass slide substrates. Thickness of the Si-N layer was fixed at 50 A, while those of the Fe-Zr-N (or Fe-Ta-N) layer T_Fe-N was changed in the range from 200 to 1000 A. For control of the film composition, a composite target was used. The area ratio of the Zr (or Ta) plate to total target area was changed in the range 0∼4.8%. Figure 1 shows the changes in coercivity H_c and saturation magnetization M_s of the Fe-Zr-N/Si-N film with annealing temperature. The changes in x-ray diffraction patterns of these films are shown in Fig. 2. It is evident from these figures that the crystal growth in the films obtained by the sputtering of 4.8%: Zr-Fe target is significantly suppressed, though the film obtained by the sputtering of 3.2%: Zr is crystallized at a temperature below 400 degree C. Soft magnetic properties of the 4.8%: Zr film are not deteriorated by the annealing at the temperature up to 550 degree C. Saturation magnetization has a tendency to increase as the annealing temperature increases. Similar results are obtained in the addition of Ta