激光和等离子处理对复合材料表面涂层附着力的影响研究

为了提高环氧涂料在纤维增强聚丙烯复合材料上的附着力,采用激光和等离子体表面前处理方法,应用超景深显微镜、粗糙度测定仪、接触角测试仪以及附着力测试仪,研究了激光和等离子体表面处理对纤维增强聚丙烯复合材料表面形貌、表面粗糙度和表面水接触角的影响,并且探究了这 2种表面处理方式对环氧涂层在复合材料上附着力的影响。结果表明： 2种处理方式均可明显提高环氧涂层在基材上的附着力,附着力均可由不到 1 MPa提高至 8 MPa以上。     

热喷涂锌-铝合金涂层对钢结构防护性能研究

通过在我国大气和水环境下的曝露腐蚀试验,以及实验室条件下的中性盐雾腐蚀、NaCl水溶液中的全浸和浸渍/干燥循环、电化学等手段,研究了铝含量对Zn-Al合金耐蚀性影响,在此基础上分析比较了热喷涂Zn85Al合金涂层与传统的Zn、Al金属涂层在耐腐蚀性和对钢基体的电化学保护的差异。研究发现,与热喷涂Zn、Al涂层相比,Zn-15Al合金涂层对钢基金属既具有热喷涂Zn涂层优良电化学保护特点,又具有热喷涂Al涂层的高耐蚀特点。目前热喷涂Zn85Al合金涂层已开始在国家水利、桥梁等重点基础设施建设项目中应用。     

AISI316奥氏体不锈钢低温渗碳层的组织及耐蚀性

为了提高奥氏体不锈钢的表面硬度并保持其良好的耐蚀性,采用自主开发的低温渗碳工艺对AISI316奥氏体不锈钢进行渗碳处理。运用金相显微镜和显微硬度计表征了渗碳强化层组织,通过电化学试验检测了渗碳强化层的耐蚀性。结果表明:渗碳温度越高,渗碳强化层表面硬度越高,耐蚀性越差;经过470℃低温渗碳处理的AISI316奥氏体不锈钢表面硬度从原来的300 HV0.25 N增加到800～1 000 HV0.25 N,有效硬化层达36.1μm,而其耐蚀性保持不变。     

冲蚀与气蚀复合磨损试验装置及其试验研究

在分析典型含沙水流的冲蚀、气蚀磨损试验设备和方法的基础上,针对我国水力机械和水工建筑的特殊损伤破坏形式提出了基于射流的水下冲蚀与气蚀复合磨损试验设备和方法。实验室泥沙冲蚀与气蚀复合磨损模拟试验结果表明,该试验装置设计合理,可以在较短时间内获得试验数据。对2种典型的耐磨不锈钢材料进行了冲蚀磨损试验研究,发现2种材料在冲蚀磨损过程中伴随有气蚀作用机制,材料损伤的实质是冲蚀与气蚀的复合磨损。     

Study on methods to optimize laser-sharpening quality,efficiency and topography

This paper aims to improve bond surface smoothness, sharpening quality and efficiency as well as control grain protrusion height. Systematic research was performed on pulsed fiber laser sharpening of a coarse-grained bronze-bonded diamond grinding wheel. The results show that bond surface smoothness is related to the laser spot overlap ratio U_c and the laser scan track overlap ratio U_l. In the range 10–70%, an increase in U_c and U_l improved the sharpened bond surface smoothness. Sharpening quality and efficiency are both related to laser power density I_p. In the range 2.115–6.344 × 10⁷ W cm⁻², an increase in I_p gradually improved sharpening efficiency, but the sharpening quality trend initially improved followed by a subsequent decline. The grain protrusion height is related to the laser scan cycles N. An excessively small N will result in an insufficient chip space such that the grinding wheel is likely blocked. Grains will likely fall off due to an insufficient holding force if N is excessively large. Compared with silicon carbide grinding wheel sharpening, a pulsed laser-sharpened grinding wheel exhibits less surface grain fall-off, better grain height uniformity, more chip space around the grain and superior grinding wheel surface topography.     

稀土氧化物对纳米抗菌陶瓷釉料性能的影响

将混合稀土氧化物添加到含银系纳米抗菌剂的陶瓷釉料中,在氧化气氛中1180℃温度下经烧成可制得纳米抗菌建筑卫生陶瓷.本实验研究了添加混合稀土氧化物对釉面质量和性能的影响.实验表明,该新釉料比不含混合稀土氧化物的纳米抗菌釉料具有更强的抗菌效果,且釉面质量良好.添加0.5 wt%的混合稀土氧化物后,釉面的白度、耐磨性、硬度、抗热震性都显著提高.     

Properties of low surface energy fluorocarbon polymers with fluoro-acrylic resins

The low surface energy fluorocarbon polymer from the synthesized fluoro-acrylic resins was developed. Then the molecule orientation principle of nonpolar and polar functional groups in the polymers was analyzed. And the contact angles of pure water drops on the surfaces of various fluoro-monomer homopolymers and interpolymers were measured. So the relation of polymers＇ fluoro-content with the surface energy was determined. The distribution of fluoric functional groups in the polymers was investigated. And the test results show that though the total fluorine content of the fluorocarbon polymers is relative few, their surface energy is really low due to the enrichment of fluoro-chains on the polymers surface.     

Passivation process of X80 pipeline steel in bicarbonate solutions

The passivation process of X80 pipeline steel in bicarbonate solutions was investigated using potentiodynamic, dynamic electro-chemical impedance spectroscopy (DEIS), and Mott-Schottky measurements. The results show that the shape of polarization curves changes with concentration. The critical ‘passive’ concentration is 0.009 mol/L for X80 pipeline steel in bicarbonate solutions. No anodic current peak exists in solutions when the concentration is lower than 0.009 mol/L, whereas there are one and two anodic...     

Enhanced surface properties and contact fatigue performance of Cr4Mo4V bearing steel subjected to ultrasonic surface rolling processing

The paper presents the experimental studies on the enhanced comprehensive properties of Cr4Mo4V bearing steel using ultrasonic surface rolling process. Considerable improvements in mechanical properties and rolling contact fatigue performance are achieved in the present study, accompanied by the characterization of surface microstructures. The ultrasonic surface rolling process promotes the formation of fine nanocrystalline structures and nano-sized elongated grains with severe deformation, leading to the increasing residual stress, micro-hardness and high temperatures hardness. The crack propagation and delamination pit in the surface after ultrasonic surface rolling process is inhibited, further enhancing the rolling contact fatigue life of Cr4Mo4V bearing steel.     

大气等离子喷涂工艺参数对Al2O3涂层性能的影响

为了提高燃烧器工艺烧嘴的使用寿命,在UMCo-50基材表面大气等离子喷涂Al2O3层。采用正交试验法对喷涂工艺参数进行了优化,运用微观形貌分析、X射线衍射分析并结合强度及显微硬度等测试方法,系统研究了喷涂主气流量、功率和送粉量对AI2O3涂层综合性能的影响规律。结果表明:喷涂主气流量、功率和送粉量对Al2O3涂层性能具有交互性影响,在40L/min Ar,48 kW和30g/min条件下可以获得性能较好的Al2O3涂层,极大地提高了UMCo-50基材的抗高温氧化和耐磨性能,使之具有广阔的应用前景。