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In order to overcome the problem of corrosion wear of AISI 316L stainless steel (SS), two kinds of composite alloying layers were prepared by a duplex treatment, consisting of Ni/nano-SiC and Ni/nano-SiO 2 predeposited by brush plating, respectively, and subsequent surface alloying with Ni-Cr-Mo-Cu by a double glow process. The microstructure of the two kinds of nanoparticle reinforced Ni-based composite alloying layers was investigated by means of SEM and TEM. The electrochemical corrosion behaviour of composite alloying layers compared with the Ni-based alloying layer and 316L SS under different conditions was characterized by potentiodynamic polarization test and electrochemical impedance spectroscopy. Results showed that under alloying temperature (1000 • C) conditions, amorphous nano-SiO 2 particles still retained the amorphous structure, whereas nano-SiC particles were decomposed and Ni, Cr reacted with SiC to form Cr 6.5 Ni 2.5 Si and Cr 23 C 6. In static acidic solution, the corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiO 2 particles interlayer is lower than that of the Ni-based alloying layer. However, the corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiO 2 particles interlayer is prominently superior to that of the Ni-based alloying layer under acidic flow medium condition and acidic slurry flow condition. The corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiC particles interlayer is evidently lower than that of the Ni-based alloying layer, but higher than that of 316L SS under all test conditions. The results show that the highly dispersive nano-SiO 2 particles are helpful in improving the corrosion wear resistance of the Ni-based alloying layer, whereas carbides and silicide phase are deleterious to that of the Ni-based alloying layer due to the fact that the preferential removal of the matrix around the precipitated phase takes place by the chemical attack of an aggressive medium.

The design of metallic card clothing, which is one of the most important devices in the textile industry, has always been based on operational experience. With the development of types of fibers and the requirements for the quality of yarns, those principles concluded by engineers seem to be losing their efficiency. Recent research found that airflow played an important role in the card process, which means airflow should be carefully studied. Computational fluid dynamics (CFD) simulation greatly helps in the analysis of airflow because the gauge between carding elements is too narrow to put in any measuring device. In the present study, with the help of CFD simulation, the air around different carding clothing with varied tooth depth was analyzed. It was concluded that the carding efficiency improvement in card clothing with lower tooth depth may be related to more concentrated air velocity at the tooth tips. This resulted in more probabilities that fibers would get through the cylinder surface at the teeth tips, so that the fibers could be caught by flat-top needles more efficiently. With this assumption, a new generation of card clothing called “double teeth” containing two teeth in a single section has been invented. The new configuration design of card clothing was then applied in several spinning mills on an industrial scale for experiments. The results showed about a 30% improvement in production at the same quality level as conventional card clothing, which implied the usefulness of the newly applied principles related to airflow. Despite the difficulty in the study of the complex carding process, the new airflow analysis method has shown an optional and worthwhile way of thinking that could make a difference in future research in the textile industry.

AnanoparticlereinforcedNi鄄basedalloyinglayerwaspreparedbyaduplexsurfacetreatmentonthe surfaceofAISI316Lstainlesssteel.ThissteelcontainedNi/nano鄄SiO 2 orNi/nano鄄SiClayerwhichwaspredeposited bybrushplatingandsubsequentsurfacealloyingwithNi鄄Cr鄄Mo鄄Cubyadoubleglowprocess.Themicrostructuresof thetwokindsofnanoparticlesthatreinforcedtheNi鄄basedalloyinglayerswereinvestigatedbyscanningelectron microscopy(SEM)andtransmissionelectronmicroscopy(TEM).Thecorrosionbehaviorsofthecompositelayersunder hydrodynamicconditionsandatdifferentrotationalspeedswerecharacterizedbycurrentresponsesatapotentialof+0.2 V,apotentiodynamicpolarizationcurveandelectrochemicalimpedancespectroscopy(EIS)underastaticstate(3.5%(w, massfraction)NaClsolution)andunderslurryflowconditions(3.5%(w)NaClsolution+10%(w)sandparticles).To assesspossibleerosion鄄corrosionmechanisms,thewornsamplesurfaceswereobservedbySEM.Electrochemicaltests showedthatthecorrosionresistanceofthecompositelayerwiththebrushplatedNi/nano鄄SiO 2 particleinterlayerwas slightlylowerthanthatofthesingleNi鄄basedalloyinglayerproducedunderstaticstateconditions.However,under hydrodynamicconditions,thecorrosionresistanceofthecompositelayerwiththebrushplatedNi/nano鄄SiO 2 particle interlayerwasobviouslysuperiortothatofthesingleNi鄄basedalloyinglayer.Thecorrosionresistanceofthe compositelayerproducedwiththebrushplatedNi/nano鄄SiCparticleinterlayerwaslowerthanthatofthesingleNi鄄