置换法化学沉积银的动力学研究

试验了影响置换化学法在铜基材上沉积金属银过程和速度的主要因素,分析诸因素对过程动力学的作用,从而建立了镀液沉积速度的经验方程.验证的结果表明,这一经验方程式对化学沉积银过程的调节和产物的控制具有一定的参考.     

金属零件熔积成形过程形状质量的可视化诊断

利用单目视觉技术进行熔积成形过程监测;借助数字图像处理技术对熔积层形貌信息进行处理获得熔积层的宽度信息;以图像处理获得的熔积层缺陷点像素坐标为源头,通过文中建立的空间定位数学模型还原其三维空间位置信息,最后进行熔积层检测试验.结果表明,文中提出的单目视觉定位数学模型和数字图像处理算法能够准确的对熔积层宽度进行非接触地实时监测,并能够对可能出现的缺陷点进行快速的识别与准确的定位.因此文中方法能够实时调整与优化快速成形过程中的熔积工艺参数,保证制件形状与尺寸精度.     

W18Cr4V高速钢基体的TiN化学气相沉积

研究了气体总流量、沉积温度、TiCl4蒸发温度、氮氢比等工艺参数对W18Cr4V高速钢基体TiN沉积速率的影响。确定了沉积过程分别为扩散控制区和表面过程控制区的试验条件。在表面过程控制区域，测定了本试验条件下W18Cr4V钢基体TiN化学气相沉积的表面过程表观活化能值为137．23kJ／mol。     

药芯焊丝混合气体保护焊的熔敷特性研究

以Ar＋CO2作为保护气体，研究了药芯焊丝混合气体保护焊的混合气体配比、焊接电流、电弧电压和气体流量对熔敷速度、熔敷系数和熔敷效率的影响。试验结果表明，At＋CO2混合气体保护焊比CO2焊的熔敷效率高，Ar气比例达到60％以上，熔敷效率显著增加。焊接工艺参数选择合适时，可以获得较高的熔敷速度、熔敷系数和熔敷效率。     

药芯焊丝混合气体保护焊的熔敷特性研究

以Ar+CO2作为保护气体,研究了药芯焊丝混合气体保护焊的混合气体配比、焊接电流、电弧电压和气体流量对熔敷速度、熔敷系数和熔敷效率的影响。试验结果表明,Ar+CO2混合气体保护焊比CO2焊的熔敷效率高,Ar气比例达到60%以上,熔敷效率显著增加。焊接工艺参数选择合适时,可以获得较高的熔敷速度、熔敷系数和熔敷效率。     

化学沉积Fe-Ni-La-P合金镀层影响因素分析

采用化学沉积的方法制备Fe-Ni-La-P合金镀层,通过重量法、电化学法分析了镀液成分对Fe-Ni-La-P镀层沉积行为的影响.结果表明,改变镀液组成和沉积工艺,沉积速度随之改变.用电化学方法计算得到的沉积速率与重量法测得的的沉积速率有相同的变化趋势.     

定向凝固镍基高温合金表面微弧火花外延沉积MCrAlY涂层

在分析微弧火花沉积工艺产生的单熔体快速凝固过程的基础上,提出将微弧火花沉积用于制备具有定向凝固特征的防护涂层.结果表明:采用微弧火花沉积可在定向凝固高温合金表面获得超细的胞状柱晶结构、外延生长的MCrAlY涂层.与激光外延生长涂层相比,微弧火花外延涂层能够保持完全的柱状晶结构,而激光外延涂层表层通常会形成等轴晶层;另外,在组织均匀性、组织粗细、界面熔合区大小等方面微弧火花涂层具有明显的优势.     

沉积气氛对电火花沉积Mo2FeB2基金属陶瓷涂层组织与性能的影响

采用电火花沉积分别在空气和氩气中制备了Mo_2FeB_2基金属陶瓷涂层,通过扫描电镜(SEM)、X射线衍射(XRD)、显微硬度计和摩擦磨损试验机研究了沉积气氛对涂层形貌、相组成、硬度和摩擦磨损性能的影响。结果表明,2种气氛中沉积所得涂层的组织结构都致密,涂层与基体间无分层,呈冶金结合的特征,但空气中沉积涂层的表面较粗糙,并发生了严重的氧化,涂层均匀性也较差。它们都主要由非晶相和马氏体相组成,但氩气中沉积的涂层含有更多的非晶相。氩气和空气中沉积涂层的最大显微硬度(HV_(0.05))分别为12 862和10 129 MPa,相差2733 MPa,前者涂层2 h的磨损量几乎仅为后者涂层的1/7,表现出更好的耐磨性。2种涂层的主要磨损机制都是疲劳磨损和磨粒磨损,但氩气中沉积涂层以疲劳磨损为主,空气中沉积涂层则以磨粒磨损为主。     

常压下MOCVD法制备Al2O3薄膜工艺的研究

在常压条件下，采用金属有机化学气相沉积（MOCVD）系统在Fe-Cr-Ni合金基片上沉积Al2O3薄膜。以仲丁醇铝（ASB）为原料，纯氮为载气，研究基片温度、ASB温度和载气流量对沉积速率的影响。采用EDS、SEM技术对Al2O3薄膜的组成进行分析。研究表明，ABS温度为125℃的工艺条件下，薄膜厚度为500μm，结合强度是梯度涂层（NiAl和Al2O3的梯度沉积）的结合强度的两倍。     

Silicon coating on ferritic steels by CVD-FBR technology

Silicon protective coatings were deposited on ferritic steels (9-12% Cr) by chemical vapour deposition by means of fluidized bed reactor (CVD-FBR). The process was performed at temperatures below 580 °C with the use of Silicon donator powder and hydrogen chloride (HCl) of activator. Thermodynamic calculations were made before the experimental study to investigate the conditions for the formation of gas precursors for the deposition of the Si coating. The samples were examined by means of optical microscopy (OM), Scanning Electron Microscopy (SEM), Energy Dispersion Spectroscopy (EDS) as well as X-ray diffraction, and the results, show the formation of dense, homogenous and thin coatings consisting of Fe₃Si.     

高效热丝GMAW焊接工艺熔敷速率试验分析

交流热丝GMAW工艺是一种高效焊接工艺,其主弧为传统GMAW电弧.填充焊丝和熔池及母材构成闭合回路,交流脉冲预热电流流经该回路,产生电阻热并预热填充焊丝.当被预热到高温的填充焊丝进入熔池后,在液态金属作用下迅速熔化.进行了高效热丝GMAW工艺的试验研究,找到填充焊丝预热电流、填充焊丝伸出长度、焊丝间距、主弧焊接规范等参...     

涂层超导体缓冲层的制备

综述了涂层超导体缓冲层的作用、可利用的材料及制备方法.着重介绍了几种制备缓冲层的真空及非真空方法,即磁控溅射法、脉冲激光沉积(PLD)、溶胶-凝胶法(sol-gel)、电沉积等.展望了对下一步涂层超导体缓冲层的制备.     

Deposition rate and morphology of carbon nanotubes at different positions in a CVD reactor

Carbon nanotubes (CNTs) were synthesized through the catalytic decomposition of a ferrocene-xylene mixture in a horizontal chemical va- por deposition reactor. The deposition rate of CNTs along the axial direction was measured. The morphology of CNTs was observed by scan- ning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the deposition rate of CNTs along the axial direction first increased and later decreased, the position achieving the maximum deposition rate was influenced by the operating conditions. The morphologies of CNTs also changed along the axial direction.     

电火花沉积层质量的影响因素研究

研究了电极材料、润湿角、工艺参数、电火花沉积设备及后处理工艺等因素对实现提高沉积层耐磨性和耐腐蚀性等目的的影响,有助于提高电火花沉积层的沉积质量,为电火花沉积实验的制定和生产提供一定的参考,有利于电火花沉积工艺的改进与推广。分析表明:用短脉冲小功率沉积和较小的润湿角电极,相关联时序控制开关电源能有效提高沉积层的质量。     

不同PVD技术沉积TiN涂层的形貌和力学性能研究

本文采用阴极弧沉积、中频磁控溅射及二者的复合技术在GCr15基底上制备了TiN涂层。通过扫描电镜、XRD谱、微米划痕测试、硬度测试以及摩擦磨损测试对涂层的组织结构和力学性能进行了表征及对比。结构表明,采用复合磁控阴极弧技术制备的TiN涂层具有较好的综合性能,如较光滑的表面、较高的结合力和硬度,故磨损率较低。     

Platinum-Iridium Alloy Films Prepared by MOCVD

Platinum-Iridium alloy films were prepared by MOCVD on Mo substrate using metal-acetylacetonate precursors. Effects of deposition conditions on composition, microstructure and mechanical properties were determined. In these experimental conditions, the purities of films are high and more than 99.0%. The films are homogeneous and monophase solid solution of Pt and Ir. Weight percentage of platinum are much higher than iridium in the alloy. Lattice constant of the alloy changes with the platinum composition. Iridium composition showing an up-down-up trend at the precursor temperature of 190~230℃ and the deposition temperature at 400~ 550℃. The hardness of Pt-Ir alloys prepared by MOCVD is three times more than the alloys prepared by casting.     

Low temperature pulsed laser deposition of textured γ′-Fe4N films on Si (1 0 0)

Low-temperature reactive pulsed laser deposition (PLD) was used to prepare iron nitride films. The textured γ′-Fe₄N films with (0 0 1)-orientation were deposited on Si (1 0 0) substrate with Fe buffer layer at a substrate temperature as low as 150 °C. The (0 0 1)-oriented γ′-Fe₄N film grew on the Fe buffer layer with a 3.5-nm thick amorphous interlayer, which eliminated the lattice mismatch stress between them. The films showed a columnar granular morphology with an average lateral grain size of approximately 110 nm. The films exhibited good soft magnetic properties with a high in-plane M_r/M_s value of 0.84. The magneto-optic Kerr effect results indicated an in-plane magnetic isotropy and confirmed the high remnant ratio of the γ′-Fe₄N films.     

活性成分对金刚石膜沉积速率和质量的影响

采用微波等离子体化学气相法合成的金刚石膜质量好,但采用常规CH4-H2气体体系,金刚石膜的沉积速率低.为此,实验研究了C2 H5OH-H2、CH4-H2-Ar和CH4-H2-N2等含有活性成分的体系下,微波功率、碳源浓度、气体压力对金刚石膜沉积速率、表面形貌、电阻率的影响.结果表明:使用含氧、氩、氮等活性成分的体系,金...     

喷射沉积过程计算机模拟

在分析喷射沉积过程主要特点的基础上,着重分析了影响喷射沉积过程各参数之间的复杂关系.这种复杂关系难以用一个简单的物理模型加以描述.目前国内外普遍使用计算机模拟的方法来预测沉积坯锭的形状与性能.讨论了模拟过程的一般方法,比较详细地叙述了金属释放、金属雾化和金属凝固等三个物理过程的模拟方法,举例说明了模拟结果和实际相符合的事实,表明了模拟结果的可靠性.最后,说明了模拟的前沿问题和热点问题.     

Gas phase synthesis of SnOx nanoparticles and characterization

Tin oxide nanoparticles with an average size ranging from 4 to 80 nm were synthesized by oxidation of tin vapor in a low vacuum (10–40 mbar) reactor containing an Ar/O₂ gas mixture. The effect of oxygen and argon partial pressure on the phase formation, size characteristics and morphology of the particles was studied by transmission electron microscopy (TEM) and X-ray diffraction (XRD) method. Electron spectroscopy chemical analysis (ESCA) was used to study the state of the particle surfaces. It was shown that with increasing the oxygen partial pressure, coarser SnO_x particles were synthesized. The ESCA shift for the tin 3d_5/2 line was 2 eV and the separation between this line and the oxygen 1s line was 44 eV. The oxygen 1s line was narrow and symmetric without the OH tail, indicating clean surface. The O/Sn ratios were estimated by using the areas of the tin and oxygen lines, and it was found that the oxidized tin vapor consisted of both SnO and SnO₂. At the oxygen concentration of 50 vol% and the total pressure of 10 mbar, the surface composition was estimated to be SnO_1.2. The particles were transformed to tetragonal SnO₂ after heat treatment at 350 °C for 24 h in air.