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埋地管線防腐陽極供應商-鎂合金犧牲陽極權威廠家
根據鋁和鋅的含量不同，性能不同，其中性能較好和獲得廣泛應用的主要是Mg-6Al-3Zn-Mn合金，其表面溶解均勻，電流效率大于50%.鋁是陽極中的主要合金元素，可與鎂形成Mg17 A112強化相，提高合金的強度。但向工業(yè)鎂中單獨添加鋁時，可形成大量的Mg Al, Mg2A13, Mg4 A13等金屬間化合物，這些金屬間化合物的存在，都會增大鎂的自腐蝕速度、加速固溶體的破壞。鋅可降低鎂的腐蝕率，減小鎂的負差異效應，提高陽極電流效率。微量的錳可抵消雜質鐵、鎳的不良影響。當錳的添加量為0.3%時，可使鐵的允許含量達到0.02%，但同時也會降低電流效率。因此，雜質鐵的含量以及相應的錳含量應盡可能低。鋁、鋅、錳的同時存在可進一步降低對工業(yè)鎂中的雜質元素含量的要求。為了獲得良好的電化學性能，Mg-AI-Zn-Mn系合金的雜質含量應嚴格控制。在相近的合金成分條件下，雜質少的合金的電流效率明顯高于含雜質多的合金。
陰極保護是基于電化學腐蝕原理的一種防腐蝕手段。美國腐蝕工程師協(xié)會對陰極保護的定義是：通過施加外加的電動勢把電極的腐蝕電位移向氧化性較低的電位而使腐蝕速率降低。犧牲陽極陰極保護就是在金屬構筑物上連接或焊接電位較負的金屬,如鋁、鋅或鎂。陽極材料不斷消耗,釋放出的電流供給被保護金屬構筑物而陰極極化，從而實現保護。外加電流陰極保護是通過外加直流電源向被保護金屬通以陰極電流，使之陰極極化。該方式主要用于保護大型或處于高土壤電阻率土壤中的金屬結構。 [1]
保護電位是指陰極保護時使金屬腐蝕停止（或可忽略）時所需的電位。實踐中，鋼鐵的保護電位常取-0.85V（CSE），也就是說，當金屬處于比-0.85V（CSE）更負的電位時，該金屬就受到了保護，腐蝕可以忽略。
According to the different contents of aluminum and zinc, the properties are different. among them, mg - 6al - 3zn - Mn alloy, which has better properties and is widely used, has a uniform surface dissolution and a current efficiency of more than 50 %. aluminum is the main alloy element in the anode and can form a mg17a112 strengthening phase with magnesium to improve the strength of the alloy. However, when aluminum is added to industrial magnesium alone, a large amount of intermetallic compounds such as mg al, mg2a13, mg4a13 can be formed. the existence of these intermetallic compounds will increase the self-corrosion rate of magnesium and accelerate the destruction of solid solution. Zinc can reduce the corrosion rate of magnesium, reduce the negative differential effect of magnesium, and improve the efficiency of anode current. Trace amount of manganese can offset the adverse effects of impurities such as iron and nickel. When the amount of manganese added is 0.3 %, the allowable content of iron can reach 0.02 %, but at the same time the current efficiency can also be reduced. Therefore, the content of impurity iron and corresponding manganese should be as low as possible. The simultaneous presence of aluminum, zinc and manganese can further reduce the requirements for impurity elements in industrial magnesium. In order to obtain good electrochemical performance, the impurity content of mg - ai - Zn - Mn alloy should be strictly controlled. Under similar alloy composition conditions, the current efficiency of alloys with less impurities is obviously higher than that of alloys with more impurities.
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