化学复合镀Ni-P/PTFE工艺研究

探讨了粒子悬浮量、镀液温度、搅拌速度、表面活性剂含量及pH值等工艺条件对Ni-P/PTFE复合镀层中PTFE粒子的含量影响。研究表明，在一定工艺条件下，当活性剂(FCE)含量达到1g/L时，可以获得粒子含量为48vol％的Ni-P/PTFE复合镀层。     

PTFE/Kevlar纤维编织材料摩擦损伤演变规律研究

目的 通过对PTFE/Kevlar纤维编织材料进行不同循环次数的往复摩擦磨损试验,研究并揭示其摩擦损伤演变规律和损伤机理.方法 采用MXW-5型摩擦磨损试验机,同时保持一定的位移和频率,对材料分别进行2、5、10 N等3种载荷等级下往复运动的不同循环次数试验.采用体视显微镜(SM)对材料磨损表面在试验过程中产生的宏观损...     

TiO_2粒子对PA6流变性能和微结构的影响

采用毛细管流变仪测试PA6/TiO2复合物熔体的流变性能,用X射线衍射仪和热重分析仪研究TiO2粒子对PA6性能的影响。结果表明:PA6/TiO2复合物熔体属于剪切变稀型流体,熔体的表观粘度随着剪切速率的升高而降低,PA6/TiO2复合物的粘流活化能比纯PA6流体的粘流活化能要高;TiO2微粒含量较少时,对PA6的结晶性能和热稳定性能基本没有影响,在含量较高时能显著提高PA6的结晶性能、热稳定性能。     

纳米WC/PTFE镍基复合电刷镀层的摩擦磨损与耐腐蚀性能

针对单一纳米颗粒电刷镀镀层综合性能存在的不足,利用电刷镀技术在45钢基材上制备含纳米WC和PTFE的镍基复合镀层。采用扫描电子显微镜观察电刷镀复合镀层的表面形貌和显微结构,球盘式摩擦磨损试验机测试其干摩擦条件下摩擦磨损性能,在pH=4浓度为0.05mmol/L的硫酸溶液中进行耐腐蚀性试验。结果表明:在镀液中添加不同含量纳米粒子,可以不同程度填补粒子之间的空缺,使镀层表面平整、光滑;含纳米WC和PTFE镍基复合镀层的耐磨损和耐腐蚀性能强于纯镍基镀层和45钢基体,这是由于纳米粒子细晶强化和弥散强化所致;当含1.5g/L纳米WC与7g/L纳米PTFE乳液的复合镀层耐磨损性能最佳;含1g/L纳米WC与5g/L纳米PTFE复合镀层的耐腐蚀性能较纯镍基复合镀层提高一倍;45钢的磨损机制是粘着磨损,纯镍基镀层的磨损机制是剥层磨损,纳米WC/PTFE镍基复合镀层的磨损机制是磨粒磨损。     

老化对PTFE/PPS复合涂层的疏水和防结冰性能的影响

目的 飞机表面涂层在服役过程中受到高温、太阳光辐射作用,容易引起微观结构的破坏,失去原有的性能。本文探究了老化对PTFE/PPS复合涂层疏水、防结冰性能的影响。方法 利用一步喷涂法在TC4基体上制备出PTFE/PPS复合涂层,使用SEM和三维形貌仪进行表面形貌分析,利用傅里叶红外光谱仪以及XPS分析涂层元素组成,在对制得的PTFE/PPS复合涂层进行高温热老化（24、48、96 h）以及太阳辐射光老化（24、48、96 h）实验后,对其进行疏水防结冰性能测试。结果 原始的PTFE/PPS复合涂层和经过24、48、72高温热老化后PTFE/PPS复合涂层的表面粗糙度分别为8.075μm、5.383μm、4.583μm、5.466μm,静态水接触角由139.70°降至132.36°、131.13°、130.36°,结冰时间由最初的346 s缩短至326 s、309 s、294 s,冰晶黏附力由最初的8.65 N增加至8.90 N、9.15 N、9.65 N。经过24、48、72 h太阳辐射光老化后,PTFE/PPS复合涂层的表面粗糙度分别为10.549μm、10.974μm、9.969μm...     

聚四氟乙烯表面PDA/TiO2复合薄膜的构建及其细胞响应性

聚四氟乙烯（PTFE）具有良好的生物稳定性,是一种被广泛应用的生物材料。利用聚多巴胺（PDA）化学及原位共沉积法,在PTFE基板表面沉积制备复合薄膜,以改善其表面的亲水性和细胞响应特性。研究结果显示,由PDA和TiO₂构成的薄膜可以有效地沉积与PTFE基板表面。薄膜均匀且与基板结合牢固,剪切强度可达23.5 MPa。薄膜中的TiO₂含量可以通过沉积液中的TiO₂水溶胶加入量调节。具有薄膜的PTFE表面成纤维细胞和成骨细胞响应性较之PTFE基板显著改进,1 d的细胞粘附试验和3 d的细胞增殖试验均显示涂层表面细胞数量显著高于无涂层的PTFE。这种在PTFE表面构建二氧化钛涂层的方法简单易行,在PTFE植入体表面修饰方面具有较好的应用前景。     

Structure and micro-tribologicai properties of PTFE/Al2O3 micro-assembling film

In order to improve the wear resistance of elastic metallic-plastic thrust bearing pad,micro-assembling PTFE/Al2O3 multi-layer film was developed by alternating radio frequency(RF)magnetron sputtering PTFE and Al2O3 targets.For enhancing the adhesion of the interfaces between PTFE and Al2O3 film,N+ implantation was employed.The structure,mechanical and micro-tribological properties were studied by XPS,X-ray photoelectron spectrometer and atomic force and friction force microscope(AFM/FFM).The results show that the multi-layer consists of Al2O3 component and crystalline PTFE.The hardness of the multi-layer modified by ion implantation is less than that of Al2O3,but its toughness is greatly improved.The friction coefficient of PTFE/ Al2 O3 multi-layer modified by ion implantation is much lower than that of Al2 O3 film,and its resistance to wear is much greater than that of PTFE film.Therefore the wear resistance of elastic metallic-plastic thrust bearing pad is greatly improved.     

Structure and micro-tribological properties of PTFE/Al_2O_3 micro-assembling film

1　INTRODUCTIONComparedwithBabbittpadsofthrustbearing ,theelasticmetallic plasticpadspossessthecombina tionofreliablerunning ,excellentperformance ,flexi bleoperation ,convenientinstallationandlongservicelife.Thereforetheelasticmetallic plasticpadsarewidelyemployedinverticalelectricmachinesofhy dropower plants .Polytetrafluoroethylene (PTFE )hasbeenusedasthesurfacematerialoftheelasticmetallic plasticpadsbecauseofitslowfrictioncoeffi cientandelectricalinsulation[1] ;butitsstrengthandwearr…     

SiC_f/Ti6Al4V/Cu复合材料的界面行为及力学性能

采用箔-纤维-箔法制备SiC_f/Ti6Al4V/Cu复合材料,研究Ti6Al4V在连续SiC纤维增强Cu基复合材料中作界面改性涂层时的界面反应结合特征.利用光学显微镜、扫描电镜和能谱仪分析复合材料显微组织、断口形貌以及SiC_f/Ti6Al4V界面和Ti6A14WCu界面的反应扩散特征.结果表明:该复合材料的抗拉强度并没有显著提高;SiC_f/Ti6Al4V界面反应非常微弱;而Ti6Al4V/Cu界面反应非常明显,主要是Ti原子与Cu原子之间的反应,反应层厚度约为20 μm;反应产物主要呈4层分布,分别为CuTi_2、CuTi、Cu_4Ti_3和Cu_4Ti.     

SiCf／Ti-6Al-4V复合材料的界面性能

采用纤维推出法测量了SiCf／Ti-6Al-4V复合材料的界面剪切强度。结果表明，热压态碳涂层和未涂层纤维与基体的界面剪切强度分别为118．2MPa和230MPa，界面脱粘发生在碳涂层或纤维与界面反应层之间。500℃，600℃和800℃退火处理后，界面剪切强度均低于热压态的强度，随退火时间的增加，500℃处理后的界面剪切强度呈下降趋势，600℃和800℃处理后呈微弱上升趋势，而且800℃处理后，界面脱粘可发生在基体／界面反应层和碳涂层或纤维／界面反应产层2个界面。     

Aging and mechanical properties of NR/BR blends

The mechanical properties and post-thermal aging properties of natural rubber (NR) and polybutadiene rubber (BR) blends at different blending ratios are investigated herein. The experimental results show that both tensile and tear strengths of NR/BR blends increase with increasing NR content. BR has a higher compression stiffness than NR. The deformation of BR is less than that of NR under the same load conditions. With regard to aging properties, both tensile stress and strain of NR/BR blends decrease after prolonged aging. In addition, the stress loss of BR is lower than that of NR, meaning that the aging resistance property of BR is superior to that of NR. Furthermore, accumulated thermal history has shifted the glass transition temperature (T _g) of NR/BR blends toward lower temperatures while the loss tangent (tan δ) value increases with prolonged thermal aging.     

黄铜/钢扩散复合双金属界面组织与性能

用扫描电镜、能谱分析和压剪试验等方法,研究了扩散退火温度与时间对黄铜/钢扩散复合双金属界面附近组织、成分和界面结合强度的影响.结果表明,通过扩散复合可使黄铜/钢界面实现良好的冶金结合;在一定温度和时间范围内,随扩散温度和时间的增加界面结合面积增大,结合强度增加,可达220MPa;界面附近发生了原子的互扩散,界面上无有害相生成.     

载荷对PTFE/AlSi10Mg复合材料摩擦磨损行为的影响

采用选区激光熔化(SLM)、浸渗和真空烧结工艺制备了以AlSi10Mg为基体的多孔骨架填充聚四氟乙烯(PTFE)的自润滑复合材料。采用往复式Bruker UMT-3摩擦试验机研究了速度为5mm/s、不同载荷下复合材料的摩擦磨损性能,并采用SEM、EDS等对其成分、结构以及摩擦学行为进行了研究。结果表明,复合材料的平均摩擦因数和磨损率随着载荷的增加呈现先增大后减小的趋势;复合材料的摩擦稳定性主要由存储在骨架中的PTFE决定。其摩擦机制主要是在载荷的作用下,当磨擦表面发生磨损时,骨架中的PTFE将磨屑捕获,形成完整的PTFE润滑层,并且发生膜的转移,从而增加了复合材料的摩擦学稳定性。     

In situ formation of Zr2Al3C4/Al2O3 composites by combustion synthesis with PTFE and thermal activations

Preparation of Zr₂Al₃C₄-Al₂O₃ in situ composites was investigated by self-propagating high-temperature synthesis (SHS) involving both aluminothermic reduction of ZrO₂ and chemical activation of PTFE (Teflon). The starting materials included ZrO₂, Al, carbon black and PTFE. In addition to the conventional SHS method, the experiments were conducted by a chemical-oven SHS (COSHS) route to thermally assist the synthesis reaction. The threshold amount of 2% (mass fraction) PTFE was required to induce self-sustaining combustion. When the conventional SHS scheme was utilized, due to low combustion temperatures between 1152 and 1272 °C and insufficient reaction time, the dominant carbide forming in the composite was ZrC instead of Zr₂Al₃C₄. On the other hand, the COSHS technique increased the combustion temperature of the reactant compact to about 1576 °C, lengthened the high-temperature duration for the reaction, and prevented Al vapor from escaping away. As a consequence, Zr₂Al₃C₄-Al₂O₃ composites with a small amount of Zr₃Al₃C₅ were obtained. The microstructure of the COSHS-derived product showed that plate-like Zr₂Al₃C₄ grains were about 2 μm in thickness and 10-30 μm in length, and most of them were closely stacked into a laminated configuration.     

6N01铝合金水冷MIG焊接头组织和性能

针对6N01铝合金熔化焊接头软化问题,研究了水冷对MIG焊接头组织和性能的影响,并与自然冷却条件下接头进行对比.金相试验结果表明,水冷使填充和盖面焊道部分熔化区变窄,焊缝近熔合线的柱状晶区变宽,焊缝内部等轴晶细化;显微硬度试验结果表明水冷条件下接头软化区范围明显变窄且硬度提高;软化区TEM观察显示水冷减少了β'析出相长大;水冷还提高了MIG焊接接头屈服强度和抗拉强度.结果表明,水冷能优化6N01铝合金MIG接头组织并提高力学性能.     

Microstructure and mechanical properties of C/C composite joint brazed with Ni-based filler

The novel Ni-based brazing filler was used to join C/C composites. When brazing temperature increased from 1080 to 1100 °C, the wetting angle decreased from 23° to 14°, and the brazing filler had good wettability on the surface of C/C composites. The brazing seam of the brazed joint consisted of Ni(s,s) and Cr₃C₂ phases. As brazing temperature increased, lots of Cr₃C₂ phases were generated at the bonding interface, and the thick reaction layer was formed. When brazing temperature was 1120 °C, the shear strength of C/C joint reached the maximum value of 31.5 MPa. The fracture path extended in the C/C matrix close to the bonding interface.     

Corrosion behaviors of Al-Si-Cu-based filler metals and 6061-T6 brazements

The corrosion behaviors of a series of Al-Si-Cu-based filler metals and the 6061-T6 butt joints brazed with these filler metals are evaluated by polarization tests and immersion tests in a 3.5% NaCl aqueous solution. For comparison, a traditional Al-12Si filler metal is also employed. The results indicate that the Al-Si-Cu-based filler metals before brazing possess much higher corrosion current densities and pitting tendencies than the Al-12Si filler metal. However, brazing of the 6061-T6 alloy with an Al-12Si filler metal produces a wider butt joint, which, in this case, creates a more extensive corrosion region. Severe galvanic corrosion occurs at the 6061-T6 joints when brazed with Al-Si-Cu-based filler metals. However, in the case of the 6061-T6/Al-12Si brazements, selective corrosion of the Al-12Si eutectic phase can be observed. The bonding strengths of the 6061-T6 butt joints brazed with various filler metals are also measured before and after the immersion tests.     

TiAl合金与C/SiC复合材料钎焊接头界面组织和性能

采用AgCu箔片对TiAl合金和C/SiC复合材料进行钎焊,研究了接头界面组织的形成及演化过程,分析了界面组织对接头性能的影响.结果表明,TiAl合金的溶解量对接头界面组织的影响较大,当钎焊温度为900℃,保温10 min时,TiAl侧观察到团块状AlCu2Ti相,并伴随少量的条状AlCuTi相和AlCu4相,靠近复合...     

靶向抑制CDK4/6的肿瘤治疗基础研究与临床应用进展

周期蛋白依赖性激酶4/6(cyclin-dependent kinase 4/6,CDK4/6) 是一类丝氨酸/苏氨酸激酶,通过与细胞周期蛋白D（cyclin D）结合,调节视网膜母细胞瘤蛋白(Rb)的磷酸化状态,Rb磷酸化后与E2F转录因子分离,释放的E2F可以自由激活一系列基因表达,参与DNA复制和细胞分裂,从而介导细胞G1/S期转换,影响细胞周期的进程。近年研究发现CDK4/6在多种肿瘤发生和发展过程中起着核心作用,已成为临床多种肿瘤治疗的重要分子靶点。本文将对CDK4/6与肿瘤的关系以及CDK4/6抑制剂临床应用的最新研究进展做一综述。