超硬薄膜涂层材料研究进展及应用

采用CVD和PVD法制备TiN．TiC．TiCN．TiAlN等硬质薄膜涂层材料已经在工具、模具、装饰等行业得到日益广泛的应用．但仍然不能满足许多难加工材料．如高硅铝合金，各种有色金属及其合金，工程塑料，非金属材料．陶瓷，复合材料（特别是金属基和陶瓷基复合材料）等加工的要求。正是这种客观需求导致了诸如金刚石膜、立方氮化硼（C-BN）和碳氮膜（CNx）以及纳米复合膜等新型超硬薄膜材料的研究进展。笔者对这些超硬材料薄膜的研究现状及工业化应用前景进行了简要的介绍和评述。     

Elastic Moduli and Hardness of Cubic Silicon Nitride

The bulk modulus B ₀= 290(5) GPa and its first pressure derivative B '₀= 4.9(6) were obtained for c -Si₃N₄ from volume versus pressure dependence. Measurements were performed under quasi-hydrostatic conditions in a diamond anvil cell to 53 GPa using synchrotron radiation and energy dispersive X-ray powder diffraction. This combined with nanoindentation measurements determined the shear modulus G ₀ of c -Si₃N₄ to be 148(16) GPa. The Vickers microhardness H _V(0.5) for dense, oxygen-free c -Si₃N₄ was estimated to be between 30 and 43 GPa. Both the elastic moduli and microhardness of c -Si₃N₄ exceed those of the hexagonal counterparts, α- and β-phases.     

纳米材料在钢结构防火涂料中的应用及前景

针对近年来钢结构防火涂料的研究现状,提出了利用纳米材料优越的性质将其应用于钢结构防火涂料中这一新的研究思路。介绍了火灾条件下对钢结构构件的破坏机理,评述了防火涂料的基本原理,综述了利用纳米材料优越的性质在钢结构防火涂料中取得的科研成果。同时预期了钢结构防火涂料的发展方向,为防火涂料的进一步发展提供了理论和方法上的参考。     

Structure,mechanical, and thermal properties of Ti1‐xAlxN/CrAlN (x = 0.48, 0.58, and 0.66) multilayered coatings

Nano‐multilayered TiAlN/CrAlN coatings combining advantages of Ti‐Al‐N and Cr‐Al‐N are considered to be promising candidates for advanced machining processes. Here, the structure and thermal properties of Ti_1‐xAl_xN/CrAlN (x = 0.48, 0.58, and 0.66) multilayered coatings as well as referential Ti_1‐xAl_xN and Cr_0.32Al_0.68N monolithic coatings were investigated. Ti_1‐xAl_xN coatings show a structural transformation from cubic structure for x = 0.48 to mixed cubic and wurtzite structure for x = 0.58 and 0.66, and Cr_0.32Al_0.68N coating exhibits a single cubic structure. Through a multilayer arrangement with Cr_0.32Al_0.68N layers, the Ti_0.52Al_0.48N and Ti_0.42Al_0.58N layers can be stabilized in their metastable cubic structure, but the Ti_0.34Al_0.66N layer still tends to crystallize in the mixed cubic and wurtzite structure. The hardness of Ti_0.52Al_0.48N/CrAlN and Ti_0.42Al_0.58N/CrAlN coatings is higher than that of corresponding monolithic coatings regardless of as‐deposited and annealed states. Especially, after annealing at 800°C, the Ti_0.52Al_0.48N/CrAlN and Ti_0.42Al_0.58N/CrAlN coatings reach their peak hardness of ~34.2 and 32.8 GPa due to the spinodal decomposition of Ti_1‐xAl_xN layers. However, the oxidation resistance of Ti_1‐xAl_xN/CrAlN coatings is mainly up to the Al content of Ti_1‐xAl_xN layers, where only the Ti_0.34Al_0.66N/CrAlN coating can survive the 10 h exposure to air at 1000°C.     

高硬度耐黄变PU-RIM材料的研究

介绍了用反应注射成型（RIM）方法制备高硬度耐黄变聚氨酯材料的配方及工艺条件,通过选择合适的聚醚多元醇、扩链剂、助剂和NCO含量,制备了综合性能良好的高硬度耐黄变聚氨酯材料。     

Theoretical Prediction of the Structure and Properties of Cubic Spinel Nitrides

The structure and properties of cubic spinel nitrides were investigated based on first-principles theoretical calculations. The lattice constants, bulk moduli, band structures, electronic bonding, and lattice stability of thirty-nine single and double nitrides were studied. The single spinel nitrides of the form c -A₃N₄ (where A is a Group IVA element), except c -Hf₃N₄, are all semiconductors with band gaps ranging from an indirect gap of 0.07 eV in c -Ti₃N₄ to a direct gap of 3.45 eV in c -Si₃N₄. For double nitrides of the form c -AB₂N₄ (where A and B are Group IVA (Ti, Zr, Hf) or IVB (C, Si, Ge, Sn) elements), both metallic and insulating band structures are possible. The stability of the double spinel nitrides, relative to single nitrides, is dependent on the optimal cation radii and polyhedral volumes at the tetrahedral A sites and the octahedral B sites. Of the thirty-two double nitrides, only nine are predicted to be energetically favorable. Among the potentially stable phases, the most interesting ones are c -CSi₂N₄ (which has an exceptionally strong covalent bonding and large bulk modulus), c -SiGe₂N₄ (which has an energetically favorable direct band gap of 1.85 eV), and c -SiTi₂N₄ (which is metallic).     

先进复合材料在飞机结构中的应用

科学技术的进步让先进复合材料的运用范畴更为广泛,随着我国对飞机结构研发的重视,复合材料以其高强度、密度小的优势被运用到飞机结构当中,研发人员不断发掘先进复合材料的潜力,提升复合材料的耐高温性能和耐疲劳性能,以强化飞机材料结构。阐述了先进复合材料在飞机结构中的具体应用以及效益情况,期望能够阐明先进复合材料的发展新趋势。     

Effects of experimental parameters on the physical properties of non-stoichiometric sputtered vanadium nitrides films

Polycrystalline vanadium nitrides thin films were deposited onto (1 0 0)-oriented silicon wafers by reactive dc planar magnetron sputtering. The influence of the nitrogen gas flow (from 0 to 15 sccm) was studied. Several substrate temperatures were investigated: 150, 400 and 650 °C. Analytical techniques including X-ray diffraction and reflectivity, atomic force microscopy and optical photospectrometry were used to characterize the structure, the morphology and the optical properties of the films. The measured thickness indicates that the deposition rate is decreased (from 3.5 Å for 0 sccm to 1.5 Å for 15 sccm) with increasing nitrogen gas flow. Obtained structures depend on the substrate temperature. The structure of pure vanadium (0 sccm) varies from amorphous phase at 150 and 400 °C to -V phase at 650 °C. The films crystallize dominantly in β-V₂N_1−x phase at low nitrogen gas flows and in δ-VN_1−x phase at high nitrogen gas flows. The as-deposited VN films were highly textured. The texture seems to depend on the nitrogen gas flow. The root mean square (rms) derived from atomic force microscopy (AFM) varies with the nitrogen gas flow. The optical reflectivity of VN films shows high values in the infrared region.     

含芴功能材料的研究与应用

从芴的结构特点出发,讨论了芴的基本性质,包括化学结构特征、酸性与反应活性、热稳定性、光谱特征;综述了含芴结构的重要有机中间体,如芴酮、芴甲醇的化学特性与应用;综述了含芴结构的高分子材料改性单体,如双酚芴、9,9-双(3-氨基-4-羟苯基)芴等,以及它们在各种材料改性中的应用;介绍了含芴结构化合物在感光与光导材料领域的应用,如9,9-二烷基芴、芴-三苯胺结构化合物、芴-偶氮结构化合物;介绍了含芴结构的电致发光材料,如聚烷基芴、芴-噻吩共聚物、芴-噁二唑共聚物等;还介绍了含芴结构的医药与农药,如苯芴醇和含芴结构的植物生长激素;另外还介绍了用于催化剂领域的含芴功能化合物。     

Organoclay-Filled Vinyl Ester Monomer Toughened Epoxy-Intercrosslinked Matrix Materials

A vinyl ester monomer (VEM), namely cyclohexyl-1,1′-bis[4-(γ-2-methylphenoxy)-α-hydroxypropylacrylate], was synthesized from 1, 1-bis (3-methyl-4-glycidyloxyphenyl) cyclohexane, and acrylic acid via nucleophilic addition. The structure of VEM was confirmed by FTIR, ¹H, ¹³C NMR, and electron impact-mass spectroscopy. Diglycidyl ethers of bisphenol-A (DGEBA) epoxy resin were toughened with varying percentages of 5, 10, and 15% (by wt) VEM using 4, 4′-diaminodiphenylmethane (DDM). VEM-modified epoxy systems were further modified with organophilic montmorillonite (OMMT) clay. OMMT clay-filled hybrid VEM-epoxy resin systems, developed in the form of casting, were characterized for their mechanical, thermomechanical, dielectric, and morphological properties.     

树脂基复合材料在混凝土结构中的应用

本文详细介绍了树脂基复合材料（FRP）的组成材料，探讨了用于混凝土结构增强和加固的树脂基复合材料的成型工艺。在此基础上，讨论了树脂基复合材料，诸如纤维聚合物筋，纤维聚合物板和纤维聚合物锚 的性能和在混凝土结构的应用现状和前景。     

合金组分对金属陶瓷覆层材料性能影响的研究

以Mo粉、FeB合金粉和Fe粉为基本原料,分别加入C,Cr,Ni或同时加入C,Cr,Ni合金元素成分,采用原位反应真空液相烧结工艺,在Q235钢基体上,制备三元硼化物基金属陶瓷覆层材料。研究了合金组分对覆层材料抗弯强度的影响以及对覆层硬度和耐磨性的影响。研究结果表明：在三元硼化物基金属陶瓷覆层中同时加入5％Cr,2％Ni,0．8％C作为合金组分是覆层的最佳组成,此时覆层材料具有高的抗弯强度,覆层的硬度和耐磨性指标优异。     

Systematic study on mechanical and electronic properties of ternary VAlN,TiAlN and WAlN systems by first-principles calculations

Transition-metal aluminium nitrides widely used as protective tool coatings are a class of materials with a combination of high hardness, outstanding wear resistance as well as good chemical stability. In this work, through a well developed structure searching method, the ground-state phase of V_0.5Al_0.5N is verified and systematically studied on its mechanical and electronic properties by comparing with Ti_0.5Al_0.5N and W_0.5Al_0.5N via first-principles calculations. Our results show that the ground-state phase of V_0.5Al_0.5N adopts a hexagonal structure of P6₃/mmc symmetry. Mechanical property studies demonstrate the hexagonal phase has a surprisingly improved hardness of about 38 GPa and enhanced ideal strengths relative to its well-known metastable cubic B1 phase whose hardness is only about 20 GPa. This mechanical enhancement greatly expands the upper limit of the strength and hardness for this type of Al-containing ternary systems. Meanwhile, detailed analysis on strength and elastic anisotropy indicates it also exhibits much better mechanical isotropy. Underlying mechanism of the mechanical enhancement is explored by the electronic analysis in-depth. The position of the E_F is tuned by the introduction of the Al element and this electronic tuning leads to a metallic-to-semiconductor transformation from B1 to the hexagonal phase and the strengthening of the bonds between the metal elements and the N atoms.     

Hydrothermal Crystal Growth,Structures and Thermal Properties of Co(II)-4,4′-bipyridine-Based Coordination Polymeric Materials

Hydrothermal synthetic parameters were studied and optimized for the preparation of new coordination polymeric materials based on Co(II) and 4,4′-bipy. A new polymeric compound, [Co₂(H₂O)₂(OH)₂(4,4′-bipy)₈](NO₃)₂·2(4,4′-bipy) 10(H₂O) (1), was prepared and structurally characterized by single crystal experiment. The framework of (1) is made up of two different one-dimensional substructures, i.e., the neutral chain A and positively charged chain B, both of which share the same nodes and node linkers. This is rarely found, especially from a one-pot crystal growth technique. Two other crystals were also identified, i.e., [Co(SO₄)(H₂O)₃(4,4′-bipy)]·2(H₂O), and K₂Co(H₂O)₆(SO₄)₂. The optimization of synthetic parameters apparently favors the formation of different polymeric structures, and this can be experimentally fine tuned. The influences of these parameters on phase formation, purity and crystal growth are discussed. The complicated thermogravimetric property of the new compound is also reported.     

On some alkali- and alkaline-earth-metal boron nitrides, unsaturated with boron

Three new lithium, magnesium and calcium boron nitrides, namely Ca₆BN₅(L), Mg₆BN₅(H) and Li₃Mg₃B₂N₅(L), were synthesized using a metal nitride–boron nitride sintering technique at low (L) or high (H) pressures. All these new compounds are typical metal boron nitride powders and, like previously known Mg₃BN₃, seem to have the N³⁻ anion in their structures.     

Reaction Synthesis of Magnesium Silicon Nitride Powder

The synthesis of magnesium silicon nitride (MgSiN₂) by direct nitridation of a Si/Mg₂Si/Mg/Si₃N₄ powder mixture is described. A nucleation period at 550°C and stepwise heat-treatment schedule up to 1350°C was adopted for the synthesis of MgSiN₂ powder, based on TG-DTA measurements. The influence of the ratio of constituents on the final phase composition also has been studied. The content of magnesium and silicon in the starting powder should fulfill the conditions Mg₂Si/Mg ≥ 3 and Si₃N₄/Si_tot≥ 0.5 to obtain single-phase MgSiN₂. The silicon particle size of <0.5 μm is preferable to decrease the time of nitridation. The oxygen content of as-synthesized powders is in the range 0.9–1.2 wt%. However, the oxygen content of MgSiN₂ powder decreases further by the addition of 2 wt% CaF₂ or 0.75 wt% carbon and reaching the lowest value of 0.45 wt% oxygen after carbothermal reduction in an alumina-tube furnace.     

新型复合防弹装甲结构材料的研究

通过分析陶瓷与复合材料的防弹机理,借助数值模拟分析技术对复合装甲的结构进行设计,并制备靶板,研究了复合装甲的材料与结构形式对防弹性能的影响,通过打靶实验,验证了结构设计的科学性及合理性.本文还在防弹装甲结构中尝试橡胶材料的应用,靶试结果表明,橡胶在防弹性能上具有明显作用.     

Using Rheology to Achieve Co-Extrusion of Cement-Based Materials with Graded Cellular Structures

Co-extrusion involves simultaneous extrusion of multiple layers and can be used to produce functionally graded materials whose layers have different properties. Rheological control is vital for successful co-extrusion. During extrusion, flow in the barrel and die land in a ram extruder should be plug-like, while the paste should be sheared and uniformly elongated in the die entry region. In the barrel of the extruder, the paste flow velocity field was inferred by direct observation of the paste left in the barrel, and evidence for plug flow in the barrel was seen only at low-extrudate velocities. In the die land, the Benbow nonlinear model was employed to assess the paste flow behavior, and plug flow was achieved only when the shear stress applied to the paste by the die land wall was smaller than its yield stress. For co-extrusion, a simple method using thin-walled tubes was found to be effective to prepare layered feedrods. Functionally graded cellular structures of cement-based materials were successfully co-extruded by using a low-extrudate velocity when the paste had decreasing shear viscosity from inner to outer layers.     

Rod-like eutectic structure of arc-melted TiB2–TiCxN1−x composite

TiB₂–TiC_xN_1−x composites were synthesized by arc-melting mixtures of TiB₂, TiC and TiN powders in a N₂ atmosphere at 60 kPa. TiB₂–TiC_xN_1−x composites were obtained at TiN contents below 20 mol%, whereas TiB formed in the composites at higher TiN contents. TiB₂–TiC_xN_1−x composites with a nominal composition of 36TiB₂–44TiC–20TiN (mol%) had a rod-like eutectic structure, where the TiC_xN_1−x single-crystal rods dispersed in the TiB₂ single-crystal matrix. The crystal orientation relationship between the TiB₂ matrix and the TiC_xN_1−x rods was TiB₂ (0 0 0 1)//TiC_xN_1−x (1 1 1). Vickers hardness (H_v) of the rod-like eutectic composite was 22.5 GPa.