激光功率对Fe基合金重熔热喷焊层组织和耐磨性的影响

利用金相显微镜和X射线衍射仪等分析手段,研究了Fe基合金热喷焊层在其他工艺参数相同的条件下,经不同激光功率重熔处理后组织结构的变化,并对其硬度和耐磨性进行了测定比较. 结果表明,Fe基合金热喷焊层的组织较粗大,经不同激光功率重熔处理后有不同程度的细化,激光功率越小,重熔热喷焊层组织越细小. Fe基合金重熔热喷焊层组织主要由g-(Fe,Ni)固溶体基体相和Cr7C3, Cr23C6及Cr2B等强化相组成,硬度和耐磨性较原始热喷焊层均有较大幅度提高,激光功率越大硬度和耐磨性越好,硬度提高约16%,耐磨性提高约55%.     

等离子喷焊耐磨涂层制备及性能分析

针对石油化工行业中关键零部件的磨损问题,采用等离子喷焊技术喷焊Fe基和N i基自熔性合金粉末,获得超厚涂层,从而达到表面改性的目的.结果表明,采用该工艺制备的涂层与基体呈冶金结合,耐磨性能相较于基体金属分别提高约6倍和4倍,大大延长了零部件的使用寿命.进而对涂层的微观组织和耐磨机理进行了分析和研究,并且与氧乙炔火焰喷焊技术所制备的涂层进行了对比测试分析,结果表明,利用等离子喷焊技术所制备的超厚涂层耐磨性能更为出色.     

铜对铁基合金激光熔覆涂层的影响

采用激光熔覆技术在Q235A钢表面制备Fe/Cu复合涂层,利用XRD,SEM,TEM和滑动磨损试验等方法研究了Cu对铁基合金激光熔覆涂层的影响.结果表明,未经时效处理的Fe/Cu熔覆层主要是由α-Fe、正交结构的M7C3和M23C6构成.在马氏体上分布着高密度的位错,而且位错沿着熔覆基材向熔覆层方向延伸分布.熔覆层经时效处理后,ε-Cu颗粒沿着M7C3相由过饱和α-Fe中弥散析出,对其周围的位错起钉扎作用.时效后熔覆层的表面耐磨性能显著提高.     

搭接率对等离子熔敷铁?镍合金涂层的组织和耐磨性的影响

采用等离子熔敷技术在高锰钢表面制备Fe-Ni合金涂层,研究了搭接率对涂层的显微组织结构、显微硬度和耐磨性的影响。结果表明:不同搭接率下,Fe-Ni合金涂层都与基体结合良好。随着搭接率增大,组织生长趋势明显,晶粒变得粗大。Fe-Ni合金涂层以α-Fe相为主,还有Co_3Fe_7和FeNi金属间化合物存在。搭接率为30%时,Fe-Ni合金涂层析出的强化相分布均匀,平均显微硬度最高,耐磨性最佳。     

碳化钨对激光熔覆层组织和耐磨性的影响

采用激光熔覆的方法在Q235钢板表面得到熔覆层,研究了激光熔覆后显微组织的变化、表层显微硬度的变化趋势及其原因及熔覆层抗磨损性能提高的幅度。结果表明：添加WC,可使熔覆层组织细化,硬度和抗磨损性能得到不同程度的提高。     

不同等离子熔覆铁基合金涂层在阀门密封面上的应用

在阀门密封面上用等离子熔覆技术制备了Fe45、Fe313和Fe316三种铁基合金涂层.利用光学显微镜、扫描电镜、能谱仪和X射线衍射仪表征了熔覆层的显微组织和物相组成.采用维氏硬度计测试了熔覆层的显微硬度,并使用电化学工作站和全浸腐蚀试验测试了它们的耐蚀性.结果表明,Fe45熔覆层呈现均匀的等轴晶组织,Fe313和Fe3...     

纳米颗粒粒径对等离子喷涂法制备氧化锆纳米涂层的影响

利用扫描电镜(SEM)、场发射扫描电镜(FESEM)、透射电镜(TEM)、比表面积吸附法(BET)等分析测试技术,研究了3种不同纳米尺寸氧化锫粉粒的造粒性能、沉积效率以及对等离子喷涂涂层晶粒大小、涂层熔融性能、结合强度的影响.结果表明:纳米氧化锆粉体一次颗粒粒径大小显著影响纳米粉体的喷雾造粒性能、沉积效率、涂层表面粗糙度、涂层晶粒粒径和结合强度大小.本试验中,利用颗粒一次粒径范围为50～70 nm的纳米氧化锆粉体,等离子喷涂制备了晶粒粒径范围为80～120 nm,沉积效率为43%,涂层表面粗糙度为5.92 μm,结合强度为27 MPa的纳米结构氧化锆涂层.     

纳米SiO2对丙烯酸罩光漆耐磨性的改性研究

经偶联剂表面处理的纳米SiO2,通过超声分散和离心处理后均匀分散在丙烯酸罩光漆中,制得了丙烯酸/纳米SiO2复合罩光漆。对该罩光漆漆膜耐磨性、附着力、磨损行为等进行了研究。研究结果表明:纳米SiO2对漆膜的摩擦行为及耐磨性等产生较大的影响,当纳米SiO2添加量为3.0%时,丙烯酸/纳米SiO2复合罩光漆漆膜的耐磨性可提高48.7%,漆膜的附着力、柔韧性、抗冲击强度等性能也得到明显改善。     

SiO2纳米粒子对 UV固化涂层硬度及耐磨性的影响

为了探究 SiO₂纳米粒子对 UV固化涂层硬度及耐磨性的影响,通过 St.ber法制备了粒径为 40 nm的 SiO₂纳米粒子,并使用硅烷偶联剂 KH570对其表面进行改性,以提高其在 UV固化树脂中的分散性。系统研究了 SiO₂纳米粒子的添加状态及硅烷偶联剂添加量对其在 UV固化涂层中分散性的影响。结果表明：使用 SiO₂纳米粒子与 UV固化活性稀释剂组成的分散液能够在 UV固化树脂中得到良好的分散,并且随着硅烷偶联剂添加量的增加,其在 UV固化树脂中的分散性逐渐提高。此外添加 SiO₂纳米粒子后涂层的双键转化率仍然维持在 70%,光固化速率基本没有变化。随着 SiO₂纳米粒子的添加量达到 10%,不同配方的光固化涂层的铅笔硬度都有 1~2个等级的提升,且耐磨性有所提高。     

Modeling of the free flight region of a cyclone transferred arc plasma reactor

The Plasmacan cyclone transferred arc plasma furnace seems ideally suited for the treatment of fine refractory powders to produce a consolidated liquid product. In this furnace, particles are pneumatically injected tangentially near the wall of a cylindrical sleeve while an arc is struck along the central axis of the sleeve. A simple model has been developed to examine the behaviour of the injected particles in the entrance region of the furnace up to the point where the particles reach their melting point and form the molten film. Three-dimensional equations of particle motion are solved to compute particle trajectories, given gas temperature and velocity fields in the furnace. The location of the first appearance of the molten film is computed under a variety of operating conditions for a laboratory scale furnace.     

高速电弧喷涂LX88A涂层的抗磨粒磨损性能

采用高速电弧喷涂工艺在Q235钢上制备了LX88A涂层。用X射线衍射研究了涂层的相组成,用扫描电子显微镜对涂层的显微结构和磨损后的形貌进行了分析,测试了涂层截面的结合强度和显微硬度,在MLS-225型湿砂橡胶轮式磨粒磨损试验机上研究了涂层的抗磨粒磨损性能。结果表明,LX88A涂层的显微硬度平均值为1123.3HV(测试力0.98N),其组织是在铁基体上弥散分布着一定量的Al2O3、Fe2B、TiB2等硬质颗粒;相对于16Mn钢,LX88A涂层的抗磨粒磨损性提高了13倍。     

The influence of carbon on the microstructure and wear resistance of alumina

The influence of carbon as a dopant on grain growth and wear resistance of polycrystalline alumina was evaluated. Carbon was introduced into alumina by sintering in a carbon-rich environment (graphite furnace under flowing He), and/or by residual carbon from organic binders used during the green body consolidation process. Samples were sintered at 1600°C for 2 h. Doping alumina with carbon resulted in a reduced grain size after sintering, correlated to solute-drag, and graphite particle-drag for high concentrations of carbon (~3 wt.%). The material response to abrasive wear was quantified by measuring the sample area cut for a defined time using a diamond wafering saw, as a function of grain size and carbon content. Sintering alumina with carbon resulted in a significant increase in wear resistance, as a result of the reduced grain size.     

High-temperature oxidation and wear resistance of WC-Co based coatings with WB addition

A new type of WC-based coating with high oxidation- and wear-resistance at elevated temperature was fabricated by thermal spraying the pre-treated WC-Co powder doped with WB. Addition of WB led to in situ formation of WCoB, which acted as a substitute for Co in the powders and the resultant coatings. It was shown by thermal analysis that WCoB has obviously higher oxidation resistance at high temperatures than that of WC and Co. Thus, the oxidation of the WC-WCoB coating was mainly initiated from WC, rather than from Co in the conventional WC-Co coatings. Most of WCoB was preserved in the coating after high-temperature wear tests. Particularly, with an addition of 40 wt.% WB, the wear rates of the WC-Co coating were dramatically decreased by 90% and 77% at the room and elevated temperatures, respectively.     

Effect of Na2SiO3 concentration on corrosion resistance and wear resistance of MAO ceramic film on the Al-Mg-Sc alloy

Although Al-Mg-Sc alloy was widely applied to aviation aerospace field, they were vulnerable to local corrosion and wear in the process of long-term service in severe environmental conditions. In this paper, micro-arc oxidation (MAO) ceramic films on Al-Mg-Sc alloy substrate were prepared in electrolyte solutions with different Na₂SiO₃ concentrations, and the corrosion resistance and wear resistance of the MAO samples were studied. The experimental results of potentiodynamic polarization (PDS) and long-term immersion tests indicated that the MAO ceramic film prepared in 10 g/L Na₂SiO₃ electrolyte solution had the best corrosion resistance, as manifested by no obvious cracks, serious collapse and corrosion products on the sample surface and no deep cracks and corrosion paths in the cross-sectional area. The increase of Na₂SiO₃ concentration in electrolyte solution also improved the wear resistance of MAO ceramic film, as manifested by low wear depth (10 μm)and width (1 mm) of the MAO ceramic film prepared in 10 g/L Na₂SiO₃ electrolyte solution against GCr15 steel ball. Studies in mechanisms suggested that as the Na₂SiO₃ concentration in the electrolyte increased, the MAO ceramic film became denser, which could prevent the penetration of corrosive medium, promote the generation of the anti-wear layer with SiO₂ as the main component to enhance the wear resistance. MAO ceramic film formed in Na₂SiO₃ electrolyte solution provided good protective performance for Al-Mg-Sc alloy in the corrosion and wear conditions, which had a broader application prospect.     

镁合金表面纳米Al2O3陶瓷涂层的制备及耐磨性研究

采用热化学反应法在MB2镁合金表面制备了含有纳米Al2O3粒子的陶瓷涂层。采用XRD分析了微米Al2O3陶瓷涂层和纳米Al2O3陶瓷涂层的相结构,并测试了这两种涂层的耐磨性及耐热冲击性。结果表明,微米级Al2O3陶瓷涂层磨粒磨损及黏着磨损耐磨性相对于镁合金基体分别提高了14%及47%,且涂层中有新相MgMnSiO4生成;纳米Al2O3陶瓷涂层耐磨性及耐热冲击性优于以微米粒子制备的陶瓷涂层,磨粒磨损及黏着磨损耐磨性相对于基体分别提高了55%及100%,涂层中产生新相Mg2SiO4和Al2SiO5。     

镁合金表面微弧氧化陶瓷膜的形成过程研究进展

归纳了镁合金表面微弧氧化过程中电解液组成及工艺条件对陶瓷膜层表面形貌、截面形貌和相组成等的影响.结合成膜过程中电压及膜层厚度的变化规律,综述了镁合金微弧氧化陶瓷膜的形成机理.     

电流密度对电镀铜-镍合金微观结构和耐蚀性的影响

采用直流电沉积法在高锰铝青铜基体上制得Cu-Ni合金镀层,镀液组成和工艺条件为:CuSO4·5H2O 20 g/L,NiSO4·6H2O 84 g/L,C6H5O7Na3·2H2O 75 g/L,十二烷基硫酸钠0.5 g/L,H3BO320 g/L,电流密度15~30 mA/cm^2,pH 7,温度55℃,搅拌速率300 r/min,时间60 min。研究了电流密度对Cu-Ni合金镀层元素成分、微观形貌和耐蚀性的影响。结果表明,在电流密度30 mA/cm^2下所得到的Cu-Ni合金镀层最厚,为25μm,耐蚀性最好,经乙酸盐雾试验168 h后表面仅有几个微小的腐蚀坑。     

阳极氧化对TC4钛合金力学与耐磨性能的影响

对比分析了脉冲阳极氧化和直流阳极氧化工艺对TC4钛合金表面形貌、拉伸性能、疲劳强度和耐磨性的影响。结果表明,脉冲阳极氧化和直流阳极氧化膜的粗糙度相较于TC4钛合金更大,而表面硬度从高至低为:脉冲阳极氧化膜>TC4钛合金>直流阳极氧化膜。虽然阳极氧化后试样的力学性能都相较于处理前有不同程度的减小,但是耐磨性有较大的提升。脉冲阳极氧化试样的疲劳强度接近TC4钛合金基材,且明显高于同样膜厚的直流阳极氧化试样,它的强度、断后伸长率和耐磨性也更优。     

铈对镁合金微弧氧化膜微观结构和耐蚀性的影响

利用扫描电镜、电化学工作站等,研究了不同铈盐添加方法对ZE10镁合金在由硅酸钠14 g/L、氟化钠14g/L、氢氧化钠2 g/L、甘油5mL/L组成的溶液中,于电压300 V、脉冲频率1 kHz、占空比15％的条件下微弧氧化20 min所得微弧氧化膜厚度、形貌和耐蚀性的影响.结果表明,先进行铈盐转化处理再微弧氧化和在电...