本文在45钢杆件表面采用化学镀方法制备了Ni-P、Ni-Co-P以及Ni-W-P三种合金镀层,比较并分析了三种镀层的物相结构、结合力、表面形貌、成分、硬度、耐磨性能和耐蚀性能,以期明确Ni-Co-P镀层、Ni-W-P镀层的适用场合,从而使杆件的耐磨性能或耐蚀性能得到更大程度的提高.结果表明,三种镀层都具有非晶态结构,与基体的结合力较好,表面粗糙度相差不大.三种镀层的硬度分别是45钢硬度的2.9倍、3倍、3.2倍,磨损量和腐蚀失重较45钢也都明显降低,都可以用作45钢的表面保护层.相比之下,Ni-Co-P镀层更适用于提高杆件的耐蚀性能,Ni-W-P镀层更适用于提高杆件的耐磨性能.
电镀加工技术是非传统的加工工艺,镀层性质的好坏依赖于电解质的组成、pH、温度、电流密度等因素.基于稳健性设计理论和变量分析,利用L9正交表实验,研究了pH和温度对镀层性质的影响.分析了pH和温度对重量、厚度和粗糙度的影响,得出了电镀加工参数的最优值,优化的工艺条件为:pH=1、温度≤40℃.优化后的电镀铜层晶粒均匀致密,表面平整,质量较佳.通过XRD图谱和高解析光学显微镜分析表面形貌证明了优化的可靠性.该设计为电沉积加工技术的深度研究提供了指导作用.
Electroless palladium plating is the most key process in new type ENEPIG printed circuit board manufacturing. In this paper,process parameters which influencing the quality were analyzed from the reaction mechanism of electroless palladium plating,and these parameters were optimized by using robust design experimental method of DOE. The optimal process parameters were founded as follows: PdCl_22. 2 g / L,NaH_2PO_2 concentration 13. 2 g / L,NH_4OH 165 m L / L,bath temperature 55 ℃,bath pH 9. 6,NH_4Cl 33 g / L. Validation tests showed that the palladium deposition rate was accelerated obviously and the concentration was increased significantly after the optimized palladium plating process had been applied.
La_2O_3 was chosen as the additive of electroforming solution for Cu-SiC composite electroforming. This paper studied the impacts of different dosage of La_2O_3 on the surface morphology and microhardness of the Cu-SiC composites. The results showed that La_2O_3 can improve the surface morphology and increase the amount of SiC deposited in the composites,make the electroforming layer structure more uniform and then increase the micro-hardness of composites materials. While the mass concentration CuSiC composites have better surface morphology,higher deposition amount of solid reinforcement phase and no obvious aggregation when the mass concentration of La_2O_3 in electroforming solution is 1. 5 g / L. In addition,the composite electroforming layer shows higher micro-hardness.
A new determination method of zinc chloride in acidic zinc plating bath was established. In this method,the ferrous ions in the plating bath were masked by ascorbic acid,the aluminum ions were masked by ammonium fluoride,the copper ions were masked by thiourea,and the zinc was determined by means of EDTA volumetry with xylenol orange as indicator under the condition of p H = 5. 4. Experiments showed that the relative average deviation of this method was 0. 09% and the recovery rate was 99. 24%,both the precision and the recovery rate were higher.
This paper proposed an ammonium ferrous sulfate volumetric method to determine the potassium permanganate content in oxide processing solution. The experiments for indicator selection,precision and standard addition recovery were carried out. The results indicated that all RSD values were less than1. 0%( n = 7) and the values of standard addition recoveries were in the range from 99. 49% to100. 61%. This method had good precision and high accuracy.
Ceramic coating with Y was prepared on 6061 aluminum alloy substrate by micro-arc oxidation method through adding Y( NO3)3into alkaline silicate electrolyte,and influences of the Y( NO3)3on thickness,roughness,micro-hardness and surface morphology of the ceramic coating were studied in this paper. Results showed that the element of Y could be detected in this ceramic coating; adding appropriate amount of Y( NO3)3could reduce roughness of the ceramic coating,improve hardness and corrosion resistance of the ceramic coating,increase thickness of the ceramic coating,and improve surface morphology of the ceramic coating significantly,the appropriate adding amount of Y( NO3)3should be 0. 003 mol / L approximately.
In this paper,dendritic copper powder for silver plating was prepared by using displacement and reduction methods,deposition process,properties of the powder,and performance of the conductive rubber which using the copper powder for silver plating as filling material were studied through SEM,energy spectrum analysis and high-temperature oxidation test. Results showed that the complexing agent YH-10 had strong complexation on silver ions,an uniform and compact silver layer was coated on the dendritic copper powder surface,the resistivity was 0. 000 1 Ω·cm and no oxide was appeared on the surface. Under the condition of 150 ℃ and 1. 5 h heat preservation,the powder had not been oxidized,which showed that the powder had high temperature resistance. Using the prepared copper powder for silver plating and the imported copper powder for silver plating as conductive filler to prepare conductive rubber respectively,various performance parameters of the two rubbers were similar.
In this paper,on basis of the introduction of common methods for sepiolite modification,such as acid-modification,heat-modification,acid / heat-modification,magnetic-modification and organic-modification,it was pointed out that the modified sepiolite had obvious advantages in improving specific surface area and adsorption performance of the sepiolite. Meanwhile,the application of acid / heat-modified and magnetic-modified sepiolite in Lead and Zinc contained wastewater treatment were introduced,and the regeneration of sepiolite of saturate adsorption was briefly summarized. Lead and Zinc contained wastewater treatment by sepiolite is a treat by waste wastewater treatment technology with good prospect for development.
In order to improve the performance of hot-dip galvanized Zn coating,varies amount of Zn-Ce master alloys were added into the Zn bath. Effects of Ce element on layer growth and microstructure of the coating were investigated by XRD,SEM and EDS analysis. Results showed that: when Ce content( Ce 0. 08%) in the bath increased,crystal grains of the Zn-Ce alloy became finer gradually and their size became more uniform; when Ce 0. 08%,some crystal grains became larger with the increasing of Ce content,and there were some small grains sandwiched among the large ones. When Ce mass concentration in the coating was 0. 08%,the thickness of δ phase remained almost the same with Ce content increasing,while the thickness of ζ phase became thinner slightly. However,when the Ce content over0. 12%,thickness of the coating would decrease dramatically.
Finishing process can significantly improve the parts surface roughness and decorative effect,and plays a fundamental role in safeguarding final appearance and performance of metal coating of the parts. Through studies on the finishing technology,research findings of mechanical finishing technology are used into the field of metal coating technology,which ensuring high precision of the parts,and the super mirror decorative effect of the parts surface has been achieved simultaneously,which making the researching has a higher application value.
Ni-5% W substrates were electro-polished in the phosphoric acid- sulfuric acid and additives system with uniform design method,and that technique was optimized by DPS( Data Processing System)software. At the same time,the experimental results were verified according to the regression equations.The surface topography of the substrates was characterized by means of metallographic microscope and AFM. The results showed that the root mean square roughness of polished substrate surface could be reduced to 3 nm or less within the range of 25 μm × 25 μm by the two regression fitting,and the experimental values and the prediction relative error of 2. 36%.
5,5-dimethyl hydantoin( DMH) was added into succinimide cyanide-free sliver plating solution,and influences of DMH dosage on appearance and gloss of the silver coating,upper limit of cathode current density,and deposition speed were investigated. Coating morphology was observed by scanning electron microscopy( SEM). Results showed that when DMH mass concentration was 20 g / L,the silver coating,with good binding force,good anti-tarnishing ability and 232 Gs gloss,could be obtained. The up limit of cathode current density was 0. 76 A / dm2 and the deposition rate was 1. 263 g /( dm2·h).
As a means of hollow glass microspheres modification,electroless plating method has the advantages of simple process and equipment,uniform coating thickness and good covering power,and the modified surface of hollow glass microspheres has been widely used as wave absorption material. In this paper,development and principle of electroless plating were briefly described,research status of Ag,Ni,Co,Cu electroless plating methods for preparation of wave absorption materials with hollow glass microspheres as base material were reviewed.
In this paper,using electrolytic copper powder and carbon fiber as raw material,copper matrix composite material reinforced by carbon fiber was prepared by cold-pressing sintering method,and the influences of carbon fiber content,carbon fiber length and carbon fiber plating on performance of the composite material were studied. Results showed that:( 1) with the increase of fiber content,density and electrical conductivity of the copper matrix composite material reinforced by carbon fiber would decrease continuously,while strength and wear resistance of the composite material would increase at first and then decreased,when the carbon fiber content was in 3%- 4. 5wt%,the composite material has better comprehensive properties.( 2) with the increase of fiber length,density,electrical conductivity and wear resistance of the copper matrix composite material reinforced by carbon fiber would decrease due to the porosity increasing and interface structure variation,while strength of the composite material would increase at first and then decreased.( 3) compared with nickel pre-plating method,the electrical conductivity of carbon fiber reinforced copper matrix composite material prepared by copper pre-plating method was increased,but the mechanical property was decreased.
This paper investigated 4 fault examples in sulfate bright nickel plating due to the variation of temperature,including nonuniform temperature of plating solution,low environmental temperature of electroplating,high temperature of plating solution and low temperature of post- processing fluid. The influence of temperature on sulfate bright nickel plating was studied. For troubleshooting,the methods and technical measures in sulfate bright nickel plating to avoid similar problems were concluded in the electroplating production.
Based on magnetic abrasive finishing,440 c stainless steel was finished by Al2O3 spherical abrasive produced by gas atomization. By orthogonal experiment design,the workpieces were processed using abrasives with different particle sizes to optimize machining parameters. Results showed that the optimized machining parameters were: S( Spindle speeds) of 2 500 r / min,δ( working gap) of 1. 5 mm,f( feed rate) of 60 mm / min,t( the amount of the Abrasive) of 2. 0 g. The original microscopic surface morphology and micro texture of workpieces could be improved. The original surface roughness was reduced from0. 450 μm to 0. 043 μm and a surface roughness of mirror face level was achieved. It was indicated that440 c stainless steel could be perfectly finished by using magnetic abrasive finishing,also it 's fatigue strength and corrosion resistance could be improved in various degrees.
Ionic liquids are the liquids composed of ions under the condition of room temperature or near room temperature,on which most of the of metals,semiconductor metals in periodic table and their compounds can be deposited out. This paper introduces the development progress,types and characteristics of ionic liquids. It also introduces the electrodeposition of metals in different ionic liquids and the opportunities as well as challenges for application.
Microwave cross-linked chitosan resin was synthesized with chitosan as raw material. Effects of synthesis conditions,such as emulsifier dosage,molecular weight of polyethylene glycol( PEG),cross-linking reaction time,on Pb2 +adsorption capacity were studied. Results showed that when PEG2000 was used as porogen,emulsifier quality was 0. 12 g,formaldehyde quality was 2 ml,epichlorohydrin quality was 5ml,cross-linking reaction time was 20 min,the resin had better Pb2 +adsorption capacity.
Titanium-hybrid silica sol and normal silica sol were prepared through sol-gel method,and their anti-corrosion coatings on Al alloy were also prepared. Salt spray test,electrochemical impedance spectroscopy( EIS) and mechanical properties of the coatings were investigated,results showed that the coating of titanium-hybrid silica sol exhibited better performance in salt spray test than that of un-hybrid silica sol,and it's EIS value was also one order of magnitude higher than that of un-hybrid silica sol; pencil hardness and the wear resistance of the titanium-hybrid silica sol coating were higher than that of un-hybrid silica sol coating,however,the impact strength was lower than that of latter.
