鎂合金熔體雜質(zhì)形態(tài)及凈化方法研究



摘    要


　　本文在分析鎂熔體熔煉過程中一系列熔煉特性和雜質(zhì)離析機(jī)理的基礎(chǔ)上，將鎂合金熔體的精煉原理和精煉工藝進(jìn)行了一定深度的歸納研究。

就氧化性說，在實(shí)際熔煉條件下，元素的氧化反應(yīng)不僅與 有關(guān)，而且與反應(yīng)物的活度和分壓有關(guān)。改變反應(yīng)物或生成物的活度與爐氣中反應(yīng)物的分壓，可影響氧化反應(yīng)進(jìn)行的趨勢(shì)、順序及程度，甚至改變反應(yīng)進(jìn)行的方向。這是進(jìn)行控制或調(diào)整氧化還原反應(yīng)的理論依據(jù)。而弄清熔煉條件下氧化反應(yīng)的機(jī)制、控制氧化反應(yīng)的環(huán)節(jié)及影響氧化速度的諸因素(溫度、濃度、氧化膜結(jié)構(gòu)及性質(zhì)等)，可有效針對(duì)具體情況，改善熔煉條件，控制氧化速度，減少組元的氧化燒損。

由分壓差脫除原理，除氫可采用精煉劑吸附脫除、吹氣精煉脫除，以及振蕩脫除。

    對(duì)混入鎂合金熔體中的雜質(zhì)，特別歸納分析了金屬雜質(zhì)Fe、Ni，因?yàn)樗鼈兪怯绊戞V合金熔體質(zhì)量的主要破壞因素；又主要討論了目前國內(nèi)使用稀土元素進(jìn)行凈化的熔劑精煉法，也綜合文獻(xiàn)資料指出吹氣精煉是今后能夠得到進(jìn)一步發(fā)展的凈化方法。




關(guān)鍵詞：鎂合金，精煉，雜質(zhì)離析


 


ABSTRACT


Based on the analysis of series of melting characteristics and mechanism on segregation impurities which are in the process of melting magnesium, the principle of refining and

refining technology of magnesium alloy melt are studied summed up with a certain

depth.

On the oxidation of that, in actual melting conditions, the elements of not only with the response, but with the reaction of the activity and the pressure on. Change the reaction of the product or activity with the gas furnace in the reaction of the pressure, can affect the trend of oxidation, and the degree of order, and even change the direction of reaction. This is the control or adjustment of the redox reaction theory. And understand melting under the conditions of the response mechanism to control oxidation of the link speed and impact of the factors (temperature, concentration, structure and nature of oxide film, etc.), to be effective against specific circumstances, improve the melting conditions, control of speed, Reduce the element of the burning.

Removal of pressure from the principle, with the exception of hydrogen can be refined removal of adsorption, inflatable refining removal, and removal of oscillation.

Among the impurities mixed in magnesium alloy melt, Fe and Ni are investigated in particular, because they are the main factor lowering the quality of magnesium alloy melt; As a current domestic method of the flux refining, also discuss the rare earth elements used to purify melt; Literatures point out that inflatable refining can be further in the future development of the purification method.




Key words: Magnesium Alloy Melt，Refining，Segregation Impurities

 


目   錄


中文摘要 Ⅰ

ABSTRACT Ⅱ

緒論 1

1 鎂熔體熔煉特性 2

  1.1 鎂的氧化性 2

    1.1.1氧化熱力學(xué)條件 2

1.1.2 氧化動(dòng)力學(xué)分析 4

1.1.3 影響氧化燒損的因素 6

1.1.4 降低氧化燒損的方法 6

1.2 鎂的吸氣性 7

1.2.1 氣體在金屬中的存在形態(tài)及來源 7

1.2.2 吸氫動(dòng)力學(xué)過程 8

1.2.3 氣體的溶解度及影響因素 9

  1.3 鎂的吸雜性 10

2 熔體精煉原理 12

  2.1除渣精煉原理 12

  2.2脫氣精煉原理 13

2.2.1 分壓差脫氣的熱力學(xué) 14

2.2.2 分壓差脫氣的動(dòng)力學(xué)分析 16

2.2.3 其他脫氣方法 17

3 熔體精煉工藝 18

  3.1 熔劑精煉法 18

3.1.1 對(duì)熔劑的要求及熔劑的組成 18

3.1.2 除去鎂中雜質(zhì)的機(jī)理 19

  3.2鎂熔體的除Fe工藝 20

3.3吹氣精煉法 23

3.3.1 吹氣精煉介質(zhì) 23

3.3.2 吹氣形式 23

3.3.3 國外幾種投入生產(chǎn)的吹氣精煉方法 25

   3.4稀土精煉 26

3.4.1 稀土與Cl元素的作用 26

3.4.2稀土去氣去雜作用 27

結(jié)論 28

參考文獻(xiàn) 29