X射线衍射仪或衍射扫描道法测定烧结矿中两价铁含量的研究

X射线衍射法代替化学法测定烧结矿中两价铁含量是X射线衍射定量相分析应用的重大成果,它不仅分析速度快、数据重现性好、操作简便,最重要的是分析结果可信度高,它直接显示了烧结矿中与两价铁有关各物相含量的变化,可直接用于控制烧结工艺的在线分析。 用X射线衍射法测定烧结矿中两价铁含量必须满足下述三项重要条件:(1)测量出与两价铁有关的全部物相X射线衍射强度;(2)测量上述各物相衍射强度时,必须扣除其他物相干扰峰的强度,测得的强度值应符合强度公式;(3)烧结矿的原料不同或配比变化时,要及时测量X射线衍射全谱图(d=5.0-1.O),进行物相鉴定,必要时应对原分析程序作适当修改。 采用X射线衍射仪可以满足上述条件的要求,而衍射扫描道法则不能。     

Cr含量对AlCrTiSiN涂层微观结构和性能的影响

采用PVD多弧离子镀技术,于450℃在高速钢试样表面制备了含铬量不同的AlCrTiSiN涂层。采用X射线衍射、X射线光电子能谱分析、纳米压痕试验、划痕试验和POD摩擦磨损试验测定了AlCrTiSiN涂层的微观结构和性能,以揭示Cr含量对涂层微观结构及性能的影响。研究结果表明:Cr含量较低的涂层主要由fcc-CrN相和少量hcp-AlN相组成;随着Cr含量的升高,hcp-AlN相衍射峰消失,涂层中出现hcp-Cr_2N相和Cr相;随着Cr含量升高,AlCrTiSiN涂层与基体的结合力增大,摩擦因数和磨损率降低;Cr含量为55.18%的涂层抗摩擦磨损性能最佳,因此可大大提高刀具的使用寿命。     

X射线衍射仪或衍射抛描道法测定烧结矿中两价铁含量的研究

Ｘ射线衍射法代替化学法测定烧结矿中两价铁含量是Ｘ射线衍射定量重大成果，它不仅分析速度快、数据重现性好、操作简便，最重要的是分析结果可信度高，它直接显示了烧结矿中与两价铁有关各物相含量的变化，可直接用于控制烧结工艺的在线分析。用Ｘ射线衍射法测定烧结矿中两价铁含量必须滞下述三项重要条件：（１）测量出与两价铁有关的全部物相Ｘ射线衍射强度；（２）测量上述各物相衍射强度时，性能扣除其他物相干 强度，测得的强     

X射线定量相分析中择优取向的衍射强度校正问题

一、引言在物相的X射线衍射定量分析中,由于择优取向,微吸收,消光等诸因素的影响,致使测量强度与理论计算强度之间存在着很大的偏离,从而引起误差;这是X射线物相定量分析中需要特别注意的,又是困难的问题。本文着重讨论择优取向对定量相分析中衍射强度的影响及其消除方法。二、基本原理消除择优取向对定量相分析影响的方法,大致分为两类:一是着眼于试样制备;二是对测得的衍射强度进行校正。为消除晶体择优取向造成的影响,Hiltz等曾将试样制成五面柱体,每一面测量三对衍射线,求取试样六个面、18组线对所测的平均值,作为该相的含量。该方法表明在     

细晶粒硬质合金预处理工艺优化及金刚石涂层性能研究

为了进一步拓展金刚石涂层刀具的产业化应用,提升金刚石涂层刀具的结合力性能,本文开展了细晶粒钨钴类硬质合金的化学预处理研究,考察了三步法预处理工艺对不同晶粒度基体形貌和成分的影响,实现了金刚石涂层与基体的高结合强度。利用扫描电子显微镜和EDS能谱仪对预处理后基体的表面形貌和钴含量以及涂层形貌进行分析,采用拉曼光谱、X 射线衍射光谱对涂层物相结构进行分析表征,并利用固体颗粒冲刷评价金刚石涂层的抗冲刷性能。结果表明:酸处理对Co的去除起着重要作用,WC晶粒越小所需酸处理的时间越长,碱处理对WC的刻蚀能力表现出先增大后减小的趋势,在3min时达到最大Co暴露量。由此分别确定了WC-6%Co(0.2,0.4,1.0 μm)基体三步法最佳工艺,三步法预处理后的基体均获得均匀致密,晶粒取向为(111)面,抗冲刷性能优异,膜基结合性能好的金刚石涂层。     

电弧离子镀沉积NiCrAlY涂层的阻尼性能

本文采用电弧离子镀沉积NiCrAlY涂层,探讨NiCrAlY涂层作为阻尼涂层的可行性并研究涂层的阻尼测试方法和阻尼特性。本文采用X射线衍射和扫描电镜等手段分别对涂层的物相结构、表面形貌以及化学成分进行了测试表征。而涂层阻尼的测试则采用动态机械分析仪和正弦扫频的方法进行,实验结果表明NiCrAlY涂层能明显提高样品的阻尼性能。     

X射线单峰衍射强度数据处理

在X射线衍射定量分析工作中,最基本的工作是对单峰X射线衍射强度数据进行处理,从中获得所需要的信息。例如点阵常数精确测定、物相定量分析、应力测定、反极图测定等,都是通过对各个单峰X射线衍射强度数据的处理,从中确定峰强、峰位、峰     

大气等离子喷涂制备Ni基TiB_2复合涂层的研究

采用化学镀Ni-B合金包覆TiB2粉,Metco-7M等离子喷涂制备TiB2/Ni-5%Al金属陶瓷涂层,研究TiB2含量对涂层的微观组织、结合强度、显微硬度的影响。用X射线衍射、SEM扫描电镜分析涂层物相组成和形貌;用线扫描能谱分析涂层与基体的界面元素分布;采用对偶件拉伸法测试涂层结合强度,用显微硬度仪测试涂层硬度。结果显示,TiB2以原始颗粒形态存在于涂层中,无TiB2的氧化产物TiO2,其他氧化产物Al2O3、NiO含量较低;涂层与低碳钢基体存在微观冶金结合;结合强度高达40 MPa,随TiB2含量增加,涂层显微硬度增大,结合强度变化不大。     

电弧喷涂铁基非晶涂层的结构与性能

用电弧喷涂技术在低碳钢基体上制备一种含非晶和纳米晶的Fe基涂层.采用X射线衍射仪(XRD)、扫描电镜(SEM)、透射电镜(TEM)、显微硬度仪分析测量涂层的组织和性能.并用谢乐公式计算晶粒尺寸.结果表明,涂层呈典型的层状组织结构,由变形良好的带状粒子相互搭接堆积而成.涂层结构致密,孔隙率低,氧化物含量较少,涂层含有非晶和纳米晶,晶粒尺寸为10~40 nm,利用X射线衍射强度比较法测量涂层中非晶相的含量为55.3%.涂层具有很高的硬度,其显微硬度最高达到1 260 HV0.1.     

高速电弧喷涂FeMnCr/Cr3C2涂层的组织与性能

采用高速电弧喷涂技术在20钢表面制备了FeMnCr/Cr3 C2涂层.结合光学显微镜、维氏硬度、X射线衍射、场发射扫描电子显微镜、能谱分析等分析方法对喷涂层的微观组织和性能进行研究.结果表明:FeMnCr/Cr3 C2涂层具有固溶体相和氧化物相相互同隔的层叠结构特点;涂层具有较高的结合强度和显微硬度,良好的抗热震性和耐高温冲蚀磨损性能.     

MULTI-PEAK MATCH INTENSITY RATIO METHOD OF QUANTITATIVE X-RAY DIFFRACTION PHASE ANALYSIS

A new method for quantitative phase analysis is proposed by using X-ray diffraction multi-peak match intensity ratio. This method can obtain the multi-peak match intensity ratio among each phase in the mixture sample by using all diffraction peak data in the mixture sample X-ray diffraction spectrum and combining the relative intensity distribution data of each phase standard peak in JCPDS card to carry on the least square method regression analysis. It is benefit to improve the precision of quantitative phase analysis that the given single line ratio which is usually adopted is taken the place of the multi-peak match intensity ratio and is used in X-ray diffraction quantitative phase analysis of the mixture sample. By analyzing four-group mixture sample, adopting multi-peak match intensity ratio and X-ray diffraction quantitative phase analysis principle of combining the adiabatic and matrix flushing method, it is tested that the experimental results are identical with theory.     

Effect of Ti content on the microstructure and mechanical properties of TiAlSiN nanocomposite coatings

TiAlSiN coatings has been proposed and studied because of their desirable properties in hardness and coating-substrate adhesion. Further improvement of their performance can be achieved by better understanding the effect of the concentration of each element on the microstructure and mechanical properties of the coatings. In this paper, the TiAlSiN coatings with different Ti content were deposited by reactive DC magnetron sputtering method. The microstructure and mechanical properties of the coatings were analyzed by energy dispersive spectroscopy, X-ray diffraction, transmission electron microscope, scanning electron microscope, nano-indentor and Rockwell indentation tester. The results reveal that TiAlSiN coatings consisted of amorphous phase and crystalline phase. With a Ti content of 63 at.%, as well as a Si content of 7 at.%, a super-hard TiAlSiN coating with a nanoindentation hardness of 66 GPa was achieved. What is more, in contrast to the well-described super-hard nanocomposite TiAlSiN coatings, another “nanocomposite” microstructure coating with a Ti content of 29 at.% in which the amorphous phase is wrapped in a crystalline phase was identified, with a comparatively low hardness value of 20 GPa. The highest adhesion strengths with a Rockwell indentation classes HF2 was achieved for a coating with a Ti content of 63 or 65 at.%.     

Microstructure evolution and mechanical properties of Ti-B-N coatings deposited by plasma-enhanced chemical vapor deposition

Ternary Ti-B-N coatings were synthesized on AISI 304 and Si wafer by plasma-enhanced chemical vapor deposition (PECVD) technique using a gaseous mixture of TiCl4,BCl3,H2,N2,and Ar.By virtue of X-ray diffraction analysis,X-ray photoelectron spectroscopy,scanning electron microscope,and high-resolution transmission electron microscope,the influences of B content on the microstructure and properties of Ti B N coatings were investigated systematically.The results indicated that the microstructure and mechanical properties of Ti-B-N coatings largely depend on the transformation from FCC-TiN phase to HCP-TiB2 phase.With increasing B content and decreasing N content in the coatings,the coating microstructure evolves gradually from FCC-TiN/a-BN to HCP-TiB2 /a-BN via FCC-TiN+HCP-TiB2/a-BN.The highest microhardness of about 34 GPa is achieved,which corresponds to the nanocomposite Ti-63%B-N (mole fraction) coating consisting of the HCP-TiB2 nano-crystallites and amorphous BN phase.The lowest friction-coefficient was observed for the nanocomposite Ti-41%B-N (mole fraction) coating consisting of the FCC-TiN nanocrystallites and amorphous BN phase     

Fabrication and microstructure of Fe-based amorphous composite coatings by laser cladding

Fe-based amorphous composite coatings were fabricated on AISI 1045 steel by laser cladding. The results of the X-ray diffraction and transmission electron microscopy analyses show the coating is composed of an amorphous phase in majority and a nanocrystalline phase in minority. Phase composition of the coating changes along the depth of the coating. The reasonable scanning speed for fabricating an amorphous composite coating is 3 500mm/min when the laser power is 4 800W and the laser beam diameter is 2mm. If the scanning speed is lower than 3 500mm/min, the intensity of the two main diffraction peaks in X-ray diffraction patterns of the coatings decreases with the scanning speeds increasing. At the same time, a broad halo peak emerges and enlarges. High laser power and fast scanning speed are the essential conditions of amorphization. The coating exhibits high microhardness.     

Formation of electroless Ni–B coatings using low temperature bath and evaluation of their characteristic properties

The formation of electroless Ni–B coatings obtained using a low temperature bath and evaluation of their characteristic properties are addressed in this paper. An alkaline bath having nickel chloride as the source of nickel and borohydride as the reducing agent was used to prepare the electroless Ni–B coatings. The influence of concentration of sodium borohydride in bath on the plating rate and the nickel/boron content of the resultant Ni–B coatings was studied. Selected coatings were characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and vibrating sample magnetometer (VSM), respectively, for assessing the phase content, phase transformation behaviour and magnetic properties. XRD patterns reveal that the structure of electroless Ni–B coatings in as-plated condition is a function of the boron content of the coating: higher the boron content, greater the amorphous nature of the coating and vice-versa. DSC traces exhibit two exothermic peaks around 300 and 420 °C, corresponding to the phase transformation of crystalline nickel and Ni₃B phases at 300 °C and the transformation of a higher phase compound to Ni₃B at 420 °C. VSM studies indicate that the magnetic properties of the coating is also a function of the boron content of the coating: higher the boron content, lesser the saturation magnetization.     

添加元素Al,La改性IP-TiN膜性能研究SCIEI

本文在离子镀TiN(IP-TiN)膜的基础上添加了6wt-％的金属元素Al和不同微量的稀土元素La(0.1,1.0,2.0wt-％),获得了改性的IP-TiN膜(称Al,La改性IP-TiN)。通过对镀膜性能的检测发现,当La含量增加到2wt-％时,镀膜与基材的附着强度明显提高;镀膜表面显微硬度、耐磨性亦随La含量增高出现有规律变化。经电子探针及X射线衍射分析认为是添加元素在镀膜与基材界面上形成较宽的使镀膜相组成及晶粒取向改变的过渡带所致。     

Co-Gd合金在尿素-乙酰胺-NaBr熔体中的电沉积及合金性能

在尿素-乙酰胺-NaBr熔盐中采用电沉积方法制备了Co-Gd合金薄膜.运用循环伏安技术研究了Gd、Co的共沉积行为.通过扫描电子显微镜、X射线能谱仪和X射线衍射仪研究了电流密度对镀层表面形貌、元素组成及镀层结构的影响.研究发现,Gd含量随着电流密度的增加呈先增加后减少的趋势,在电流密度为12.5 mA/cm2时达到最大含量54.97%(质量分数).镀层的表面形貌随着Gd含量的增加而变得粗糙.镀态时镀层结构为非晶态,300 ℃热处理后转化为Co(Fm3m)相,在600 ℃热处理后又出现GdCo5 (P6/mmm)相.采用振动样品磁强计测试了镀层的磁性能.结果表明,镀层中Gd的含量对镀层的磁性能有重要影响.在热处理过程中,镀层的饱和强度在600 ℃热处理时达到最大值550.43 kA/m,而矫顽力则在400 ℃热处理时达到最大值34.97 kA/m.     

碳化铬基金属陶瓷电火花沉积涂层的微观组织与性能

采用电火花沉积分别制备了碳化铬基金属陶瓷单涂层和碳化铬基金属陶瓷/Ni复合涂层。采用X射线衍射仪(XRD)、扫描电镜(SEM)、显微硬度计和摩擦磨损试验机对比研究了单涂层和复合涂层的物相、微观组织结构、显微硬度和摩擦磨损性能。结果表明,两种涂层组织结构致密,与基体呈良好的冶金结合,并在涂层内形成了纳米晶的微观组织。复合涂层中FeCr_0.29Ni_0.16C_0.06韧性相含量增加,在涂层界面处存在过渡层Ni,并以塑性变形的方式释放了更多沉积时产生的热应力,因而涂层裂纹明显减少。复合涂层的峰值硬度(1186HV_0.05)虽略低于单涂层,但该涂层具有最小的摩擦系数(0.2462),1h磨损量仅为单涂层的1/3,因此表现出更好的耐磨性能,其主要磨损机制为磨粒磨损和疲劳磨损。     

Ti-Al-N 涂层的组织结构与摩擦学性能

目的采用多元等离子体注入与沉积(MPIIID)技术制备Ti-Al-N涂层,系统研究涂层的微观组织结构、力学性能与摩擦学特性。方法借助XRD,XPS,SEM和TEM等,观察分析Ti-Al-N涂层的微观组织结构与物相组成,采用纳米压入试验仪、布氏硬度试验仪、摩擦磨损试验仪和激光共聚焦显微镜等测试分析Ti-Al-N涂层的力学性能、膜基结合力和摩擦磨损性能。结果 Ti-Al-N涂层表现出较高的膜-基结合强度。Al元素掺杂诱发Ti-Al-N涂层发生严重晶格畸变。当Al原子数分数为6.18%时,Ti-Al-N涂层以c-TiAlN相结构为主,表现出超高硬度(达到39.83 GPa);随着Al元素含量增加,涂层中的软质h-TiAlN相结构增多,硬度随之下降。摩擦试验结果表明,低Al含量Ti-Al-N涂层的抗磨损能力良好,其主要磨损机制为磨粒磨损;高Al含量Ti-Al-N涂层的抗磨损能力较差,其主要磨损机制倾向粘着磨损。结论 MPIIID技术成功实现了Ti-Al-N涂层的低温制备与成分调控,低Al含量的Ti-Al-N涂层具有优良的力学性能和优异的抗磨损能力。     

32Cr2MoV钢表面电泳沉积氧化铝和氧化锆涂层*

采用电泳沉积法以硝酸铝和硝酸钇为溶胶原料,在溶胶制备过程中加入钇稳氧化锆(YSZ),然后利用电泳沉积和热压滤烧结相结合方法在32Cr2MoV钢表面制备氧化铝和氧化锆涂层。用扫描电子显微镜(SEM)对涂层表面及界面形貌进行观察,利用X射线衍射仪(XRD)对涂层物相组成进行分析,采用热循环氧化试验研究涂层对基体在900℃空气中高温氧化行为的影响。结果表明,利用电泳沉积法在32Cr2MoV钢表面制备了一层致密陶瓷涂层,经热压滤烧结后涂层由表层α-Al2O3和ZrO2、次表层Fe的氧化物以及靠近基体的Fe、Mo、Cr氧化物层组成,经900℃热循环氧化试验表明,陶瓷复合涂层对基体32Cr2MoV钢起到了一定的抗氧化保护作用。