渗硼注氮复合处理表面硬化层研究

采用渗硼工艺和新型的等离子体源氮离子注入技术对Cr12MoV钢进行复合处理 ,获得了高硬度的表面硬化层。用XPS对硬化层进行相分析和性能试验 ,结果表明 :硬化层主要由立方氮化硼 (C BN)和FeB组成 ,硬化层具有很高的硬度和耐磨性     

硼对高铬铸铁铸渗层组织和性能的影响

本工作利用自熔铸渗技术在ZG45钢表面复合不同硼含量的高铬铸铁铸渗层,研究了硼对高铬铸铁铸渗层组织和性能的影响.利用相图计算软件Thermo-Calc计算分析了不同硼含量下铸渗层的凝固过程,并采用SEM-EDS、XRD和显微硬度仪对不同成分铸渗层的微观组织和硬度进行分析.结果表明:铸渗层与ZG45钢基体达到冶金结合,在结合界面处未观察到微孔洞、微裂纹等缺陷,获得了厚度为10～12 mm的铸渗层.不含硼的铸渗层组织由α-Fe和α-Fe+M7 C3共晶组织组成.加入微量的硼元素后,铸渗层组织主要由α-Fe与α-Fe+M7 C3+M2 B共晶组织组成,与相图计算结果基本吻合.随着硼含量的增加,共晶组织逐渐细化,M7 C3碳化物含量减少,M2 B型硼化物增多,铸渗层硬度逐渐增加.当硼含量为0.72％(质量分数)时,铸渗层硬度最高达到1190HV.对铸态试样进行淬火+低温回火热处理后,铸渗层共晶硼化物与碳化物发生聚集长大,同时在铸渗层基体中伴有二次相的析出,试样铸渗层的洛氏硬度均有提升.热处理试样冲击磨损实验表明,铸渗层磨损表面主要以切削犁沟、疲劳剥层和剥落坑为主,并有少量微小的凿坑.硼含量为0.72％(质量分数)时,试样的抗冲击磨损性能最佳.     

稀土对H13钢固体渗硼层高温摩擦磨损性能的影响

研究了稀土氯化物CeCl3添加量对H13钢固体渗硼层截面形貌、显微硬度、表面粗糙度以及相组成的影响,以及稀土催渗辅助渗硼H13钢的高温摩擦磨损性能。结果表明:添加2.5%和5%的稀土显著提高渗硼层厚度、显微硬度与致密性,但是表面粗糙度略有提高;10%稀土渗硼试样的渗层最厚,但是其显微硬度、致密性明显下降,表面粗糙度提高;稀土辅助渗硼层中除Fe2B相外还出现了(Fe,Cr)2B相;与不加稀土渗硼试样相比,5%稀土渗硼试样的渗层磨穿时间约增加一倍,磨损率降低21%;5%稀土渗硼试样磨损率比未渗硼H13钢降低了61%,并且也低于10%稀土渗硼试样。因此,加入5%稀土催渗辅助渗硼H13钢的高温耐磨损性能较优。     

激光处理技术对渗硼层组织与性能的影响

钢材表面经渗硼处理将会提高耐磨性,但同时也使脆性增大并产生剥落现象。采用激光技术通过改变硬化层结构,大幅度改善了表面性能。本文利用各种分析手段,系统地研究了45＃钢渗硼层显微组织特征及其变化规律.认为:(1)硬化层脆性化合物明显细化,(2)渗硼层出现了硬度低于硼化铁的组织以及,(3)显微组织在渗硼层的分布合理,导致硬度梯度平缓,是降低渗硼层脆性的主要原因。     

12Cr13马氏体不锈钢B/C化学热处理的研究

研究了固体硼碳共渗及复合渗技术工艺参数对12Cr13马氏体不锈钢的组织和性能的影响。共渗方面对12Cr13钢进行不同硼碳比例的固体硼碳共渗热处理;复合渗方面对12Cr13马氏体不锈钢先进行固体渗碳,然后再进行渗硼处理,得出最优的复合渗参数。对最优参数下的共渗及复合渗12Cr13马氏体不锈钢试样进行显微硬度、XRD物相结构、电化学下耐腐蚀和摩擦磨损性能检测分析。结果表明：共渗温度950℃、共渗6 h条件下,硼碳共渗最优渗剂硼碳比为6∶4;化学渗6 h条件下,硼碳复合渗最优参数为950℃渗碳,950℃渗硼;硼碳共渗和复合渗试件经过最终热处理(淬火+低温回火)后,表层组织硬度最高可达1 507.3 HV_{0.98 N},心部硬度为420.6 HV_{0.98 N},最优参数下硼碳共渗及复合渗渗层厚度分别为976μm和1 125μm;电化学测试表明硼碳共渗和硼碳复合渗处理后材料的耐蚀性有所提高,共渗腐蚀电位为-0.578 V,复合渗为-0.582 V。磨损试验显示硼碳共渗和硼碳复合渗后经化学热处理可以显著提高12Cr13马氏体不锈钢的耐磨性能。     

H13钢双保温固体渗硼高温磨损机理

研究了H13钢高能喷丸辅助双保温固体渗硼试样和未渗硼试样的高温摩擦磨损性能,并探讨了磨损机理。结果表明,高能喷丸辅助双保温固体渗硼后的试样得到Fe2B单相渗硼层,高能喷丸能显著提高固体渗硼效率;渗硼试样的高温磨损率比未渗硼试样降低了30%,表明渗硼提高了H13钢的高温耐磨损性能。渗硼和未渗硼试样高温摩擦磨损后磨损表面均形成了氧化层,氧化物为Fe2O3。渗硼层在高温下具有较高的硬度及良好的抗氧化性,因此渗硼试样的高温磨损机理主要是渗硼层的疲劳剥落和氧化磨损,而未渗硼试样的高温磨损机理主要为氧化磨损和磨粒磨损协同机制。     

液-固界面反应法制备c-BN纳米晶

通过高能脉冲激光诱导丙酮-六方氮化硼界面反应制备出了立方氮化硼纳米晶体,透射电子显微镜分析表明制备的立方氮化硼(c-BN)纳米晶体为直径约30～80nm的类球状晶体。傅立叶变换红外光谱和X射线衍射都分别用来表征c-BN的结构。     

20CrMo钢渗碳渗硼再淬火复合处理后的机械性能

本文通过20CrMo钢的渗碳渗硼再淬火复合处理,讨论了渗层的硬度分布和耐磨性能;对渗层的接触疲劳性能进行了对比试验.试验表明,经过渗碳渗硼的复合处理,接触疲劳寿命有显著提高,为牙轮钻头渗碳渗硼新工艺提供了机械性能方面的重要依据.用上述工艺试制了一批牙轮钻头,现场试验表明,钻头使用寿命可提高40～60%.     

高质量立方氮化硼薄膜的射频磁控溅射制备及其性能表征

运用射频磁控溅射法在硅片上制备了立方氮化硼薄膜,并对射频功率、气体分压比及衬底偏压等参数对膜中立方氮化硼(c-BN)含量的影响进行了研究.采用傅立叶红外光谱(FTIR)、拉曼光谱、X射线光电子能谱(XPS)和原子力显微镜(AFM)对c-BN薄膜进行了表征和分析.结果表明:300 W的射频功率是制备c-BN薄膜的最佳条件;当气体分压比Ar/N2=5:1时,制备的薄膜中c-BN含量相对最高;立方氮化硼的形成存在偏压阈值(约80 V),低于此偏压c-BN很难形成.拉曼光谱分析进一步确认了BN薄膜的晶相结构.AFM和XPS分析结果表明c-BN薄膜结晶良好,晶粒尺寸细小,具有很好的化学配比,B原子与N原子的含量比为1:l.     

氩弧重熔对20G钢渗硼层组织结构和耐磨性能的影响

为了降低渗硼层的脆性,提高其耐磨性,对20G钢渗硼层进行了氩弧重熔处理,研究了渗硼层重熔前后的形貌、相结构、显微硬度及耐磨性。结果表明：渗硼层由FeB和Fe2B两相组成,经氩弧重熔处理后FeB相消除,氩弧重熔渗硼层由Fe23（C,B）6和Fe2B相组成,包括氩弧重熔区和过渡区;氩弧重熔处理使渗硼层表层微观硬度降低,且使...     

Laser boronising of Ti–6Al–4V as a result of laser alloying with pre-placed BN

This paper discusses the effect of CO₂ laser alloying of pre-placed BN coating with Ti–6Al–4V alloy. The formation of titanium boride and titanium nitride investigated using energy dispersive X-ray diffraction (EDXRD) result were related to the microhardness and microstructure. The nitrogen and boron diffusion during the laser boronising process identified using secondary ion mass spectrometry (SIMS) and X-ray photoelectron spectrometry (XPS) analysis was compared with the EDXRD results. The surface hardness HV1500–1700 observed at the boronised layer was five to six times higher than that of untreated Ti–6Al–4V alloy. This was compared with needle platelet and dendrite type microstructures. Theoretically estimated surface temperature values were used to interpret the compound formation in the laser alloyed layer.     

高速钢基体离子注氮对c-BN薄膜制备的影响研究

采用射频磁控溅射法在离子注氮的高速钢基体上沉积制备c-BN薄膜,主要研究离子注氮层对c-BN薄膜相结构和内应力的影响;采用各种现代分析方法对沉积的薄膜进行了表征分析,包括傅立叶红外光谱(FTIR)、X射线光电子能谱(XPS)和原子力显微镜(AFM)等分析方法;试验结果表明:高速钢基体上离子注氮有利于立方氮化硼含量的提高和薄膜内应力的降低,同时注氮处理的高速钢基体上沉积的薄膜表面形貌平整,结晶性较好.并采用X射线衍射分析(XRD)对高速钢基体的离子注氮层进行了相结构分析,探索研究了离子注氮层对c-BN薄膜生长的影响.     

Cubic phase content and structure of BN films from an X-ray absorption study

X-ray absorption near-edge structure (XANES) was used to study the cubic boron nitride (c-BN) content in the BN films deposited on various substrates by different physical vapor deposition or plasma-enhanced chemical vapor deposition methods. By fitting the XANES curves of thin-film samples using standard spectra of pure c-BN and sp(2)-bonded BN in the films with suitable weight factors, the c-BN contents at the film's surface region and across the film's thickness have been determined quantitatively. The results agree well with the previous transmission electron microscopic observations. The method is proved to be independent of the optical properties of thin film and provides a possibility to evaluate the cubic content of BN films accurately.     

The Influence of Nitrogen and Boron Implant into Silicon Substrate on the Phase and Internal Stress of c-BN Films

Cubic boron nitride(c-BN) film was deposited on a Si (100) substrate by the RF-magnetron sputtering.The mainly problems for fabrication of c-BN films are the low purity and high intrinsic compressive stress. In order to solve the two problems, the c-BN film with the buffer interlayer was deposited on the substrate which had been implanted with nitrogen and/or boron ions. The results show: the implantation of nitrogen ions can obviously increase c-BN content and reduce the internal stress slightly; while the implantation of boron shows no obvious improvement to the content of c-BN, which can reduce the internal stress in the film obviously. In addition, it is suggested that the implantation of nitrogen and boron shows the best result, which not only can increase the content of c-BN, but also reduce the internal stress in the c-BN film obviously.     

Mechanism of nucleation and growth of cubic boron nitride thin films

The mechanism and the crystallography of the nucleation and growth of cubic boron nitride (c-BN) films deposited on 〈100〉-oriented silicon substrate by RF bias sputtering have been studied by means of cross-sectional high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy. Both methods provide experimental information showing no sp²-bonded BN layer formation in the subsurface region of c-BN phase. This is clear evidence for layer-by-layer homoepitaxial growth of cubic boron nitride without graphitic monolayers in the near-surface region of the film. The turbostratic boron nitride (t-BN) consists of thin sub-layers, 0.5–2 nm thick, growing in such a way that a sub-layer normal is almost parallel to the growth direction. t-BN also comprises a large volume fraction of the grain boundaries with high interface energies. The present result and the finding by Shtansky et al. [Acta Mater. 48, 3745 (2000)], who showed that an individual sub-layer consists of parallel lamellae in both the hexagonal +h-BN) and rhombohedral (r-BN) configurations, demonstrate that high intrinsic stress in the films is due to the complex structure of sp²-bonded BN. The crystallography of c-BN films indicates heteroepitaxial nucleation of cubic phase on the graphitic BN structural precursor. The present results are consistent with stress-induced c-BN formation.     

c—BN薄膜研究进展

立方氮化硼（ｃ－ ＢＮ） 在机械、热、电子及光学方面有许多优异性能,因此世界上有很多研究人员从事ｃ－ ＢＮ 薄膜制备的研究,近年来薄膜沉积技术和ｃ－ ＢＮ 薄膜质量都已取得显著进步。介绍ｃ － ＢＮ 薄膜的用途、结构、制备方法及存在的问题。重点总结了控制ｃ－ ＢＮ 相形成的关键因素及ｃ－ ＢＮ 相形成机理。     

Boron nitride stamp for ultra-violet nanoimprinting lithography fabricated by focused ion beam lithography

Cubic boron nitride (c-BN) is one of the hardest known materials (second after diamond). It has a high level of chemical resistance and high UV transmittance. In this study, a stamp for ultra-violet nanoimprint lithography (UV-NIL) was fabricated using a bi-layered BN film deposited on a quartz substrate. Deposition of the BN was done using RF magnetron sputtering. A hexagonal boron nitride (h-BN) layer was deposited for 30?min before c-BN was deposited for 30?min. The thickness of the film was measured as 160?nm. The phase of the c-BN layer was investigated using Fourier transform infrared (FTIR) spectrometry, and it was found that the c-BN layer has a 40% cubic phase. The deposited film was patterned using focused ion beam (FIB) lithography for use as a UV-NIL stamp. Line patterns were fabricated with the line width and line distance set at 150 and 150?nm, respectively. The patterning process was performed by applying different currents to observe the effect of the current value on the pattern profile. The fabricated patterns were investigated using AFM, and it was found that the pattern fabricated by applying a current value of 50?picoamperes (pA) has a better profile with a 65?nm line depth. The UV transmittance of the 160?nm thick film was measured to be 70-86%. The hardness and modulus of the BN was measured to be 12 and 150?GPa, respectively. The water contact angle of the stamp surface was measured at 75°. The stamp was applied to UV-NIL without coating with an anti-adhesion layer. Successful imprinting was proved via scanning electron microscope (SEM) images of the imprinted resin.     

Structural evolution of boron nitride films grown on diamond buffer-layers

Boron nitride films on diamond buffer layers of varying grain size, surface roughness and crystallinity are deposited by the reaction of B₂H₆ and NH₃ in a mixture of H₂ and Ar via microwave plasma-assisted chemical vapor deposition. Various forms of boron nitride, including amorphous α-BN, hexagonal h-BN, turbostratic t-BN, rhombohedral r-BN, explosion E-BN, wurzitic w-BN and cubic c-BN, are detected in the BN films grown on different diamond buffer layers at varying distances from the interface of diamond and BN layers. The c-BN content in the BN films is inversely proportional to the surface roughness of the diamond buffer layers. Cubic boron nitride can directly grow on smooth nanocrystalline diamond films, while precursor layers consisting of various sp²-bonded BN phases are formed prior to the growth of c-BN film on rough microcrystalline diamond films.     

立方氮化硼薄膜制备与性质研究新进展

立方氮化硼(c-BN)具有优异的物理和化学性质, 在力学、光学和电子学等方面有着广泛的应用前景. 自上世纪80年代开始, 低压沉积c-BN薄膜的研究迅速发展, 到90年代中期达到高潮, 随后进展缓慢, c-BN薄膜研究转入低潮. 近年来, c-BN薄膜研究在几方面取得了突破, 如获得与衬底粘附良好、厚度超过1μm的c-BN厚膜; 成功实现了c-BN单晶薄膜的异质外延生长; 此外, 在c-BN薄膜力学性质和过渡层微结构研究方面也取得了进展. 本文主要评述最近几年c-BN薄膜研究在以上几方面取得的最新进展.     

金属等离子体浸没离子注入改善9Cr18轴承钢表面耐磨性的研究

采用新改进的阴极弧金属等离子体源 ,对 9Cr18轴承钢进行了金属等离子体浸没离子注入 (PIII)处理。首先将Ti,Mo和W离子分别注入到 9Cr18钢的表面 ,然后再对其进行N等离子体浸没离子注入 ,从而在 9Cr18钢表面形成了一层超硬耐磨的改性层。对PIII处理后的试样进行了显微硬度和磨损特性测试 ,结果表明 ,经PIII处理后的试样表面的显微硬度和耐磨性显著提高 ,而其中经Ti和Mo注入再进行N离子注入的试样效果更为明显。与仅进行N离子注入的试样相比 ,金属加N离子注入的试样表面耐磨性提高幅度更大 ,表明金属PIII在改善 9Cr18钢表面性能方面具有广阔的应用前景。XPS分析结果表明 ,PIII处理后试样表面形成了超硬的氮化物相 ,它们在改善材料表面特性中起到了重要的作用。