内凝胶工艺结合碳热氮化法制备ZrN纳米粉体

采用内凝胶工艺制得无定形的氧化锆凝胶与炭黑均匀混合的前驱体粉末,获得的前驱体在氮气条件下进行碳热氮化处理后得到氮化锆(ZrN)纳米粉体。结合热重/差式扫描量热分析(TGA/DSC)、X射线衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)等手段,对内凝胶前驱体的热处理行为、所得产物的物相组成、微观形貌及显微结构等进行了表征。研究结果表明,氮化温度的升高有利于氮化程度的提高,1400℃氮化温度下可得到纯相纳米ZrN粉体;此外,碳的引入在热处理过程中起到了必要的还原作用,且碳的加入量需要适当,C/Zr摩尔比接近2是获得纯相ZrN粉体产物较为合适的条件。     

不同氮分压下磁控溅射ZrN对钛/瓷结合的影响

探讨不同氮分压下磁控溅射氮化锆(ZrN)涂层对纯钛与低熔瓷粉(Vita钛瓷粉系统)结合强度的影响。60个纯钛基片随机分为1个对照组和3个实验组。实验组分别在不同氮分压下(Ta组1.0×10-2Pa,Tb组5.0×10-2Pa和Tc组10.0×10-2Pa)溅射沉积ZrN涂层。纯钛试样经表面处理后在烤瓷炉中进行烧结。用XRD检测到ZrN立方新相。万能试验机测试钛瓷试样三点抗弯强度,对照组为(26.67±0.88)MPa,实验组分别为:Ta(49.41±0.55)MPa,Tb(54.55±0.69)MPa和Tc(46.24±0.53)MPa,四组间差别均有统计学意义(P<0.05)。SEM观察表明,实验组钛/瓷结合良好,钛基底残留的瓷断面数量较多,面积较大。不同氮分压下溅射沉积的ZrN涂层对钛/瓷结合的增强程度有所不同,5.0×10-2Pa下钛/瓷结合增强最为明显。     

Stress evolution in magnetron sputtered Ti-Zr-N and Ti-Ta-N films studied by in situ wafer curvature: Role of energetic particles

Stress evolution during reactive magnetron sputtering of binary TiN, ZrN and TaN thin films as well as ternary Ti-Zr-N and Ti-Ta-N solid-solutions was studied using real-time wafer curvature measurements. The energy of the incoming particles (sputtered atoms, backscattered Ar, ions) was tuned by changing either the metal target (M_Ti = 47.9, M_Zr = 91.2 and M_Ta = 180.9 g/mol), the plasma conditions (effect of pressure, substrate bias or magnetron configuration) for a given target or by combining different metal targets during co-sputtering. Experimental results were discussed using the average energy of the incoming species, as calculated using Monte-Carlo simulations (SRIM code). In the early stage of growth, a rapid evolution to compressive stress states is noticed for all films. A reversal towards tensile stress is observed with increasing thickness at low energetic deposition conditions, revealing the presence of stress gradients. The tensile stress is ascribed to the development of a ‘zone T’ columnar growth with intercolumnar voids and rough surface. At higher energetic deposition conditions, the atomic peening mechanism is predominant: the stress remains largely compressive and dense films with more globular microstructure and smooth surface are obtained.     

Influence of growth rate on the structural and morphological properties of TiN, ZrN and TiN/ZrN multilayers

The effect of the deposition rate on the structural and morphological properties of TiN and ZrN single layers and TiN/ZrN multilayers deposited by radiofrequency reactive magnetron sputtering has been studied. The total pressure was kept constant and the growth rate variation was obtained by small difference of nitrogen concentration in the fed gas. The decreasing deposition rate results in a structural change in the thin films from (111) orientation to (100) one. As consequence the surface morphology becomes smoother. Films roughness is strongly related with texture and it decreases with an increase in the (100) X-ray diffraction line intensity. In order to achieve a clear interpretation of our experimental results, the ratio between the N⁺ ions of the plasma and the atoms number reaching the substrate was considered. At high deposition rate with respect to the N⁺ concentration, the chemical potential of transition metal on (100) growth surface is higher than (111) one favouring the (111) orientation of the films. On the contrary, when the growth rate is low with respect to the nitrogen concentration, the chemical potential of transition metal on (111) growth surface is higher than the (100) one leading to a preferential growth in the (100) direction.     

Sliding wear behaviour of ZrN and (Zr, 12 wt% Hf)N coatings

In the present study, the sliding wear resistances of ZrN and (Zr, 12 wt% Hf)N coatings deposited on a hardened AISI D2 tool steel by arc-physical vapor deposition (PVD) technique were examined by a ball-on-disc wear tester. Alloying of ZrN coating with 12 wt% Hf did not change the hardness significantly, but achieved an improvement on adhesion strength and dry sliding wear resistance against steel (AISI 52100-55HRC) and Al₂O₃ balls.     

Ti／ZrN／瓷界面微观结构和力学性能

通过磁控溅射法在纯钛表面溅射了一层ZrN涂层,研究了Ti/ZrN/瓷界面组织和力学性能.结果表明,Ti/瓷界面由富含Ti,Si,O元素的反应层和钛表面氧化层组成.钛表面溅射ZrN涂层后,Ti/瓷界面的连接转变为Ti/ZrN/瓷界面的连接,ZrN涂层能有效地防止钛表面生成过厚的氧化层.Ti/ZrN/瓷结合强度为29.2MPa,与Ti/瓷结合强度23.5MPa相比,提高了24.3%.     

Oxidation behavior of TiN/ZrN multilayers annealed in air

Using reactive radio frequency magnetron sputtering, TiN/ZrN multilayers were deposited on Si (111) substrates at 550 °C. The multilayers were annealed at different temperatures ranging from 500 to 1100 °C in air. The variation of the annealed multilayers has been investigated by X-ray diffraction and transmission electron microscopy. A layer-by-layer oxidation behavior is found in the multilayers annealed at temperatures below 900 °C. The oxidation mechanism of multilayers is discussed in the paper.     

ZrO_2（Y－TZP）－Si_3N_4复合材料中抑制ZrN生成研究

研究了气氛加压烧成ＺｒＯ２（Ｙ－ＴＺＰ）－Ｓｉ３Ｎ４复合材料中抑制ＺｒＮ生成工艺问题，相组成分析表明：无论添加２０ｗｔ％工业ＺｒＯ２或者Ｙ－ＴＺＰ（３ｍｏｌ％Ｙ。Ｏ。）的氯化硅复合材料，在低于１８５０℃，３ＭＰａｋ气压力下烧成，表面无ＺｒＮ生成．通过加入有效的烧结助剂（Ｙ。Ｏａ＋ＡＩ。Ｏｓ）、增加埋粉中ＳＩＯ分压以及增加保护气氛氮气压力，适当的烧成条件等工艺措施可有效地抑制ＺｒＮ的生成．实验还证实了ＺｒＮ很容易氧化，含有ＺｒＮ的ＺｒＯ。（Ｙ－ＴＺＰ）－ＳｉｓＮ。复合材料试样经９００℃，０．ｓｈ热处理已粉碎性裂开．     

Effect of NbN and ZrN films formed by magnetron sputtering on Ti and porcelain bonding

Niobium nitride (NbN) and zirconium nitride (ZrN) were deposited on Ti substrates by direct-current (DC) reactive magnetron sputtering; the deposited NbN and ZrN films served as intermediate layers of a Ti and porcelain interface. X-ray diffraction (XRD) results proved that the deposited NbN and ZrN films were polycrystalline with a cubic microstructure. The Ti and porcelain bonding strength of the samples in Group Control (27.2 ± 0.75 MPa), Group NbN (43.1 ± 0.59 MPa), and Group ZrN (52.4 ± 0.80 MPa) were measured. The surface roughness in the case of Group Control (1.863 ± 0.10 μm), Group NbN (2.343 ± 0.07 μm), and Group ZrN (2.346 ± 0.10 μm) was also investigated. Statistical analysis showed that both films helped improve the Ti and porcelain bonding strength and increase the surface roughness. Scanning electron microscopy (SEM) results showed that no apparent oxide layer was formed at the Ti and porcelain interface in both Group NbN and Group ZrN. Energy-dispersive X-ray spectroscopy (EDS) results showed that ZrN was more effective in preventing Ti oxidation than was NbN. Overall, the experimental results showed that the deposition of both NbN and ZrN films helps improve the Ti and porcelain bonding strength and that ZrN films are more effective.