热化学反应喷涂Al2O3基复合陶瓷涂层的制备及其性能

使用热化学反应热喷涂技术,在紫铜表面喷涂制备Al2O3基复合陶瓷涂层.利用XRD和SEM分析该复合陶瓷涂层物相组成和组织形貌,并对其热震性能、抗高温氧化性能和磨损性能进行测试.结果表明:采用热化学反应喷涂法在紫铜表面制备的陶瓷涂层内部生成陶瓷过渡相Al1.4Si0.3O2.7和Al1.9Si0.5O2.95等,在陶瓷涂层与Ni-Al过渡层间存在金属间化合物AlNi3;该复合陶瓷涂层熔化率较高,表面呈珊瑚状;涂层与紫铜基体结合牢靠,具有优异的高温抗氧化能力,其磨粒和粘着磨损比紫铜基体分别提高10倍和15倍.     

等离子喷涂粉煤灰复合涂层的制备及性能

利用煤炭固体废弃物,采用等离子喷涂技术,在工业纯铜表面制备粉煤灰复合涂层。利用SEM和XRD分析涂层的组织形貌和物相组成,通过热震实验、抗氧化性实验、磨粒磨损实验、冲蚀磨损实验分别测试涂层的热震性、抗氧化性、磨粒磨损性和冲蚀磨损性。结果表明:涂层表面致密,结合性良好,且有3Al2O3·2SiO2、AlB2和Al9Si等新相产生;涂层具有良好的热震性能,热震次数达到74次;涂层具有良好的抗氧化性和耐磨性,其抗氧化性、磨粒磨损性和冲蚀磨损性比基体分别提高了3.14倍、6.16倍和7.48倍。     

热喷涂合成Fe3Al基涂层的高温摩擦学特性

采用自制的新型热喷涂粉芯丝材和高速电弧喷涂技术成功制备出Fe3Al金属化合物基合金涂层，对涂层的组织、成分和相结构进行了初步分析，并测试了涂层在室温至650℃的摩擦学特性。结果表明：Fe3Al涂层的基体相由含29％Al(摩尔分数)的Fe3Al和FeAl二相混合物组成，Fe3Al／WC涂层基体为Fe-26％Al(摩尔分数)合金；添加少量WC硬质相的Fe3Al／WC涂层具有良好的高温减摩特性和耐磨性，450℃和650℃其相对耐磨性分别比20g钢高1．92倍和9．23倍；WC／W2C硬质相对Fe3Al基体的强化作用，以及涂层表面形成具有自保护作用的高硬度致密氧化膜是Fe3Al／WC涂层高温耐磨性提高的主要原因。     

激光熔覆Fe-Al-Si复合涂层研究

采用激光熔覆技术在Q235钢表面制备Fe-Al复合涂层和Fe-Al-Si复合涂层.利用X射线衍射仪和扫描电镜等方法分别研究两种涂层的物相和微观组织,并测试其显微硬度和耐磨性,同时进行对比分析.结果表明:Fe-Al复合涂层主要由Fe、Al、Al2O3、Fe3Al等相组成,而Fe-Al-Si复合涂层主要由Fe、SiO2以及Al2Fe3Si4等相组成;Fe-Al复合涂层内部存在孔隙缺陷,而Fe-Al-Si复合涂层内部无裂纹、气孔等,组织更均匀细小,与基体之间冶金结合良好;Fe-Al-Si复合涂层的显微硬度和耐磨性均约为Fe-Al复合涂层的1.8倍.     

海洋平台用S355钢表面电弧喷涂Al涂层组织及性能

利用电弧喷涂工艺在S355钢表面进行了喷涂Al涂层,通过SEM、EDS、XRD对试样表面-界面进行了形貌、物相、面扫描和线扫描分析。用能谱面扫描观察了涂层表面化学元素分布状态,并结合界面的能谱面扫描和线扫描分析,讨论了涂层与基体的结合机理。采用质量分数为3.5%Na Cl溶液进行了电化学性能测试,检验了Al涂层的耐腐蚀性能。结果表明,电弧喷涂Al涂层在S355基体表面形成均匀、致密、结合良好的Al涂层,其物相为纯Al和α-(Al Fe),其中α-(Al Fe)出现在扩散层;Al和O元素在涂层表面形成富集区,形成致密氧化膜对Al涂层进行保护;Al元素在结合界面形成富集层,其原子浓度发生阶梯过渡变化,在扩散层中发生Fe-Al化合反应,形成冶金结合方式;Al涂层极化曲线发生正向移动,耐腐蚀性较好,对S355钢基体起到了保护作用。     

Q235钢表面氩弧熔覆Mo-Si复合涂层组织和性能分析

以钼粉、硅粉为原料,利用氩弧熔覆技术在Q235钢基材表面原位合成了FeMoSi/Fe3Si金属硅化物复合涂层,应用SEM,XRD对涂层的显微组织和物相进行了分析,并测试了涂层显微硬度和常温耐磨性.结果表明,复合涂层与基体界面无气孔、裂纹,呈冶金结合;复合材料涂层由α-Fe,初生相FeMoSi三元金属硅化物树枝晶和枝晶间的鱼骨状FeMoSi/Fe3Si共晶组织组成;涂层的显微硬度达到1 000 HVO.2,较基体提高3倍左右;相对耐磨性较基体Q235钢提高近11倍.     

HK40耐热钢热浸镀Al工艺

研究了在浸镀Al液中加入Si和稀土对HK40耐热钢热浸镀Al层的影响。应用光学显微镜、扫描电镜等分析了镀层的微观组织和成分分布,应用X射线衍射仪分析了镀层的相结构,并对基体到镀层的不同区域进行了显微硬度测试。结果表明,Si和稀土的加入,使镀层变薄,表面更光滑,镀层和基体的结合更好,镀层组织中出现了较多的FeAl3和Fe2Al5相,大大提高了过渡层的显微硬度。     

球磨对镁合金反应热喷涂陶瓷涂层耐蚀性影响

在AZ31B镁合金表面采用相同配方、不同工艺(机械研磨和球磨团聚)制备复合喷涂粉末,并利用火焰热喷涂工艺制备陶瓷涂层,通过对涂层物相分析、致密性和热震性能测试、耐蚀性测试分析球磨对涂层耐磨性影响。实验结果表明:机械研磨法陶瓷涂层使基体耐酸性提高12.91倍,耐盐性提高7.46倍;球磨团聚法陶瓷涂层使基体耐酸性提高22.34倍,耐盐性提高7.68倍,球磨团聚法更适合制备热喷涂陶瓷涂层。     

20钢表面喷涂Al_2O_3陶瓷涂层组织与隔热性能研究

采用等离子喷涂技术在20钢表面制备Al2O3陶瓷涂层。利用扫描电镜、能谱仪、X射线衍射仪对涂层的微观组织、成分及物相组成进行了表征,在不同温度下对试样进行隔热性能测试。结果表明:涂层厚约0.40 mm,涂层截面是由涂层和许多孔洞组成,20钢基体与过渡层以及陶瓷层与过渡层之间形成良好的机械结合界面;涂层内主要含有SiO2、Al2O3、Na2O、NaAlO2;喷涂陶瓷涂层后,隔热性能明显提高,在550℃时Al2O3陶瓷涂层能使试样表面温度降低80℃左右。     

热喷涂铝过渡层对FEP涂层与钢基体结合强度的影响

研究了喷砂工艺和热喷涂铝过渡层对聚全氟乙丙烯(fluoroethylenepropylene,FEP)涂层与钢基体结合强度的影响.结果表明,喷砂处理后,涂层和基体结合强度随基体表面粗糙度增加先增后降.采用热喷涂工艺在钢基体上制备了铝过渡层,用扫描电镜和表面粗糙度测量仪研究了喷砂以及铝过渡层的表面形貌和表面粗糙度,用拉开法测定了FEP涂层和钢基体的结合强度.铝过渡层具有粗糙多孔的表面结构,在一定程度上增进了 FEP涂层与基体的结合强度.     

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.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

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.     

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。     

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.