Ni-P-PTFE 化学复合镀工艺优化及镀层性能研究

目的研究表面活性剂FC4和PTFE添加量,对Ni-P-PTFE化学复合镀层质量和镀层中PTFE体积分数的影响规律以及对镀层的摩擦磨损性能的影响。方法改变镀液中FC4和PTFE添加量,获得不同的Ni-P-PTFE化学复合镀层,用扫描电子显微镜观察镀层形貌,用能谱仪并结合直方图方法测算镀层中PTFE的体积分数,研究镀层质量和镀层中PTFE的体积分数随镀液中FC4和PTFE添加量的变化规律,测试镀层的摩擦学性能。结果 Ni-P-PTFE复合镀工艺中FC4的用量为0.3 g/L时镀层表面质量最好,镀层中PTFE体积分数最大;PTFE体积分数为10%时Ni-P-PTFE复合镀层的磨损率最小。结论镀层中PTFE的体积分数随镀液中PTFE添加量的增加而增加,对镀层磨损率的减小存在最优值。     

工艺参数对石墨表面化学镀铜的影响

采用化学镀法在石墨增强体表面镀覆铜层,以改善石墨/Cu的润湿性。研究了镀液成分、石墨装载量、施镀温度对镀层的影响。结果表明:含锌粉的镀液成分简单不易分解、反应温度较低、环保无污染,且镀铜层均匀致密;石墨装载量为7.96 dm2/L时,铜镀覆层最致密;施镀温度为30℃时镀层最佳。     

电流密度和施镀温度对铝合金表面Ni-SiC-MoS2复合镀层显微组织的影响

目的研究电镀工艺参数中的电流密度和施镀温度对铝合金表面Ni-Si C-MoS_2复合镀层组织形貌及成分的影响。方法利用复合电镀的方法在铝合金上制备Ni-Si C-MoS_2复合镀层。通过扫描电子显微镜、能谱仪以及显微硬度仪,分析不同电流密度和施镀温度下复合镀层的组织结构、成分、界面之间的结合情况以及显微硬度。结果电流密度为4 A/dm2时,镀层与基体的结合差,镀层表面粗糙不平;当电流密度增加到5 A/dm2时,镀层与基体结合紧密,并且镀层表面平整;当电流密度增大到6 A/dm2时,镀层表面平整度变差。施镀温度为40℃时,镀层厚度较薄;施镀温度为50℃时,镀层与基体结合良好,镀层表面平整;当施镀温度上升到60℃时,镀层与基体结合处出现裂纹,镀层质量下降。随电流密度和施镀温度的升高,镀层中Si C和MoS_2摩尔分数先增加后减小,显微硬度先增大后减小。结论采用复合电镀的方法在铝合金表面可以制备出Ni-Si C-MoS_2复合镀层,当电流密度为5 A/dm2、施镀温度为50℃时,制备出的Ni-Si C-MoS_2复合镀层表面平整,厚度均匀,Si C与MoS_2摩尔分数可分别达到10.40%和0.77%。复合镀层的显微硬度与其Si C含量成正比,最高可达357.7HV0.01,是基体合金硬度的3.7倍。     

Ni-P-W-石墨复合镀层工艺及性能研究

研究了电流密度、电沉积时间、镀液中石墨含量、镀液中钨酸钠含量、阳极类型等因素对电沉积Ni-P-W-石墨复合镀层中石墨含量、镀速、外观的影响,确定了复合镀层的最佳工艺条件为:以Ni为阳极、电沉积时间为0.5h、镀液中石墨的含量是20g/L、镀液中钨酸钠的含量是10g/L、电流密度是2A/dm2.并对镀层的形貌、耐蚀性、抗氧化性进行了测定,结果表明:与Ni-P-W复合镀层相比,Ni-P-W-石墨复合镀层有良好的综合性能.     

稀土对Ni-P-SiC复合镀层的工艺及性能的研究

研究了稀土化合物对化学复合镀Ni-P-SiC镀液稳定性、镀速、镀层中SiC含量及镀层性能的影响;并对镀层的表面形貌进行了测定.结果表明:复合稀土的适量加入有利于延长镀液的使用周期,加快施镀速度,所得镀层表面光亮均匀,耐腐蚀性能较强.     

化学复合镀Ni-P-石墨镀层的研究

用化学复合镀方法在45钢基体上镀覆Ni-P-石墨复合镀层，用扫描电镜(SEM)研究了镀层的表面形貌；研究了不同的施镀温度和不同剂量的活性剂对镀层结合力的影响，以及热处理对镀层结合力和显微硬度的影响，结果表明；当施镀温度约在75℃、活性剂的添加量在3g／L左右时，镀层结合力达到最佳；随热处理温度的提高，镀层结合力降低；约在200℃时，镀层硬度达到最高。     

金刚石复合镀层的工艺研究

研究了Ni-P-金刚石化学镀液主要成分、pH值、温度以及时间等工艺参数,通过正交实验对金刚石复合镀施镀工艺参数进行了优化,探讨了镀液成分及工艺参数对镀层沉积厚度、镀层中金刚石微粒含量及分布的影响。结果表明,采用合适的工艺条件,可得到金剐石含量较高、均匀分布的复合镀层,Ni-P-金刚石复合化学镀层硬度可达1850 HV0．1左右,耐磨性比化学镀Ni-P大大提高。     

镍-金刚石复合刷镀的工艺

河南信阳空军第一航空学院研究了镍-金刚石复合电刷镀工艺中施镀电压、施镀温度和镀笔与工件之间相对速度对复合镀层中金刚石含量和耐磨性能的影响，得到了制备高耐磨性镀层的最佳工艺参数，     

Ni—P—Al2O3化学复合镀工艺研究

简要叙述化学复合镀的机理和特点,并就新近研究成功的Ni-P-Al_2O_3化学复合镀的施镀工艺、镀液的调整与控制进行详尽的阐述,介绍实行该工艺所获得的镀层的优异性能。     

金刚石复合镀层的工艺研究

研究了Ni-P-金刚石化学镀液主要成分、pH值、温度以及时问等工艺参数，通过正交实验对金刚石复合镀施镀工艺参数进行了优化，探讨了镀液成分及工艺参数对镀层沉积厚度、镀层中金刚石微粒含量及分布的影响。结果表明，采用合适的工艺条件，可得到金刚石含量较高、均匀分布的复合镀层，Ni-P-金刚石复合化学镀层硬度可达1850HV0．1左右，耐磨性比化学镀Ni-P大大提高。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

A STUDY OF TEMPERATURE-DEPENDENT VALENCE BOND STRUCTURE OF TITANIUM

On the basis of energy and shape method for the determination of the valence bond (VB) structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is e_c~(2.9907) · (s_c~(0.4980) d_c~(2.4927)) ef1.0093 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.     

Structural Optimization of Electromagnetic Swirling Flow in Nozzle of Slab Continuous Casting

During the slab continuous casting process, the flow field of molten steel in the mold plays a decisive role in the quality of the slab. In this paper, electromagnetic swirling flow in nozzle technology is proposed to control the flow field in mold.This technology can drive molten steel to rotate inside the submerged entry nozzle by electromagnetic force, thereby controlling the flow field. This research shows that it can reduce the impact of molten steel on the bottom of nozzle and partly reduce the negative pressure at the upper part of nozzle outlet which is even eliminated by optimizing the structure and angle of nozzle. The area of heat flux of the mold wall becomes larger, and the crest value of heat flux gets lower than that without swirling in nozzle and any nozzle optimization. The meniscus fluctuates smoothly, and the flow velocity at the top surface is within a reasonable range. The temperature field distribution in the mold is uniform which was beneficial to the growth of equiaxed crystal and decreased element segregation.