本文選題：超臨界CO_2流體 + 納米金剛石　； 參考：《江蘇理工學院》2015年碩士論文

【摘要】：超臨界流體復合電鑄技術是基于電沉積原理,集金屬復合材料制備與成形為一體的精密成形制造技術,近年來新發(fā)展起來的制備高性能結構件行之有效的方法。本文圍繞超臨界二氧化碳流體納米復合電鑄技術,對其工藝過程開展數(shù)值模擬、試驗研究與分析。(1)構造三維電鑄體系模型,利用Comsol Multiphysics有限元分析軟件,耦合分析了電場分布、流場分布、電鑄層厚度分布情況和陰極表面鎳離子濃度變化規(guī)律。研究表明對于平板型電鑄,在中部區(qū)域,電場分布較為均勻,與外加電流密度相符,在邊緣處,由于形狀變化,電流密度呈激增趨勢。對于微細電鑄,電場線在微結構入口處彎曲程度和稠密度逐漸加大,微結構中間部分電場線較少,微結構邊緣處電場線稠密,且進入微結構以后電場線變得方向一致,微結構內(nèi)部的電場分布穩(wěn)定均勻有次序。電鑄層生長情況仿真值與電流密度分布相符合,陰極表面鎳離子濃度呈先減少后增大的趨勢。(2)提出了超臨界納米金剛石復合電鑄工藝優(yōu)化方法,獲得了影響電鑄層性能的工藝規(guī)律,利用自主研發(fā)的超臨界電沉積裝置,開展其工藝試驗研究。通過正交試驗,得出影響電鑄層顯微硬度的各工藝參數(shù)順序與最佳值分別為(從大到小):電流密度(9A/dm2)、金剛石添加量(60g/L)超臨界壓力(14MPa)超臨界溫度(40℃)。通過單因素試驗,分析研究了各工藝參數(shù)對電鑄層顯微硬度和表面微觀形貌的影響規(guī)律。研究發(fā)現(xiàn),SCF-CO2條件下,由于其良好的傳質擴散性、混溶性和潤濕特性,制備的Ni-diamond復合電鑄層顯微硬度可達954HV(200g),比普通條件下提高80%,且復合粒子均勻性顯著提高,說明采用超臨界環(huán)境對制備的Ni-diamond復合電鑄層的更具力學性能優(yōu)勢;從XRD圖譜中發(fā)現(xiàn),和普通環(huán)境下相比,超臨界環(huán)境下鎳結晶面擇優(yōu)取向強弱有所變化,其中晶面(111)上的衍射峰被抑制,晶面(200)上的衍射峰得到加強。(3)開展SCF-CO2復合電鑄應用基礎研究,成功制備微細復合電鑄件。在平板電鑄的工藝參數(shù)基礎上,針對“十字”型微細結構,開展復合電鑄工藝研究,分析了各工藝參數(shù)對其表面形貌影響規(guī)律,并為下一步工程化應用打下了良好的基礎。
[Abstract]:The technology of supercritical fluid composite electroforming is based on the principle of electrodeposition and the precision forming technology of the preparation and forming of metal composite. In recent years, a new method for preparing high performance structural parts has been developed. This paper focuses on the technological process of the supercritical carbon dioxide fluid nanocomposite electroforming technology. Simulation, experimental research and analysis. (1) constructing a three-dimensional electroforming system model, using Comsol Multiphysics finite element analysis software, coupled analysis of the distribution of electric field, the distribution of flow field, the thickness distribution of the electroforming layer and the change law of the concentration of nickel ions on the cathode surface. The research shows that the distribution of electric field is more uniform in the middle region of the plate type electroforming, and the distribution of the electric field is more uniform in the middle region. The current density is consistent with the current density, and the current density increases sharply at the edge. For micro electroforming, the degree and density of the electric field line at the entrance of the micro structure are gradually increased, the electric field line in the middle part of the micro structure is less, the electric field line is dense at the edge of the micro structure, and the electric field line becomes the same in the direction of micro structure, and the direction of the electric field becomes uniform after the micro structure. The distribution of electric field in the structure is stable and uniform. The simulation value of the growth of the electroforming layer conforms to the distribution of current density, and the concentration of nickel ions on the cathode surface decreases first and then increases. (2) the optimization method of the supercritical nano diamond composite electroforming process is put forward, and the process law of the performance of the electroforming layer is obtained, and the independent research and development of the electroforming layer is obtained. Through orthogonal test, the sequence and optimum value of the technological parameters affecting the microhardness of the electroforming layer are (from large to small): current density (9A/dm2) and the supercritical pressure (60g/L) supercritical pressure (14MPa) at supercritical temperature (40). Through a single factor test, the analysis and study of each of the various parameters of the microhardness of the electroforming layer are obtained. The effect of process parameters on the microhardness and surface micromorphology of the electroforming layer was investigated. The results showed that under SCF-CO2 conditions, the microhardness of the prepared Ni-diamond composite electroforming layer was up to 954HV (200g) due to its good mass transfer diffusibility, miscibility and wetting properties, which was 80% higher than that under the ordinary condition, and the uniformity of the composite particles was greatly improved. The Ni-diamond composite electroforming layer has a more mechanical advantage over the supercritical environment. It is found from the XRD map that the preferred orientation strength of the nickel crystal surface changes in the supercritical environment, in which the diffraction peak on the crystal surface (111) is suppressed and the diffraction peak on the crystal surface (200) is strengthened. (3) the SCF-CO2 recombination is carried out. Based on the technological parameters of the plate electroforming, based on the technological parameters of the flat plate electroforming, the study of the composite electroforming process is carried out on the basis of the "cross" micro structure. The influence of the process parameters on the surface morphology is analyzed, and a good foundation is laid for the next engineering application.
【學位授予單位】：江蘇理工學院
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TQ153.4

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相關期刊論文 前2條

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2 胡美些;王寧;李鵬飛;史海濤;王三軍;;氧化鈰在電鑄吸塑銅模具中的應用研究[J];特種鑄造及有色合金;2006年12期

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