耐候钢表面锈层稳定化处理技术的研究

发布时间：2018-03-28 19:18

本文选题：耐候钢　切入点：海岸大气　出处：《沈阳理工大学》2015年硕士论文

【摘要】：耐候钢暴露在大气中,其表面能够生成与基体结合性良好的保护性锈层,从而无需进行表面防护处理即可以在一些环境中直接使用。但是在自然环境下裸露使用时,在形成稳定锈层之前钢表面会发生锈液流挂、飞散等现象,造成了环境污染等问题,制约了其发展。为了解决这个问题,20世纪60年代初,日本首先开发了耐候钢表面锈层稳定化处理技术,实施该技术能够促进锈层由γ-Fe OOH向α-Fe OOH转变,缩短稳定锈层形成的时间。目前国内技术还不成熟,因此研究开发出成本较低,且应用范围较广的耐候钢表面锈层稳定化处理技术,具有显著的经济效益和工程价值。耐候钢表面锈层稳定化处理技术研究的主要内容包括能够促进耐候钢表面尽快形成均匀致密的稳定化锈层的物质(我们称之为稳定剂)的选取,以及耐候钢表面稳定化处理时采用的有机涂膜材料的选取。本文以低成本、全候型Mn Cu P耐候钢对研究对象,主要在稳定剂的选取方面进行了初探,即:本文采用实验室模拟大气腐蚀干/湿交替实验、X-射线衍射、动电位极化曲线、电化学阻抗谱等方法研究了海岸大气环境中Cr2(SO4)3和Na NO2浓度对Mn Cu P耐候钢表面锈层稳定化过程的影响。主要工作包括以下几个方面:研究了模拟海岸大气中Cr2(SO4)3的添加对Mn Cu P耐候钢腐蚀行为的影响。通过60次干/湿交替大气腐蚀实验发现,海岸大气模拟液中Cr2(SO4)3的添加可以明显降低Mn Cu P钢的腐蚀速率,加速表面锈层的稳定化。但是,Cr2(SO4)3的添加对Mn Cu P钢腐蚀行为的影响存在浓度极值现象。在本研究的实验条件下,当模拟液中Cr2(SO4)3浓度为0.02mass%时,Mn Cu P钢的腐蚀增重最小且优先进入稳定化状态。研究了模拟海岸大气中Na NO2的添加对Mn Cu P耐候钢腐蚀行为的影响。通过60次干/湿交替大气腐蚀实验发现,海岸大气模拟液中Na NO2的添加可以明显降低Mn Cu P钢的腐蚀速率,加速表面锈层的稳定化。但是,较高浓度的Na NO2使得Mn Cu P钢的腐蚀速率太小,不利于钢表面尽快形成保护性锈层。在本研究的实验条件下,当模拟液中Na NO2浓度为0.005 mass%时,Mn Cu P钢的腐蚀增重最小且优先进入稳定化状态。在所有模拟环境中,Mn Cu P钢表面锈层均由α-Fe OOH,β-Fe OOH,γ-Fe OOH和Fe3O4组成;模拟液中少量Cr2(SO4)3的存在抑制了β-Fe OOH的形成,促进了Fe3O4的形成,但是,较多含量Cr2(SO4)3的存在又抑制了β-Fe OOH向Fe3O4的还原;模拟液中少量Na NO2的存在促进了Fe3O4的形成,但是由于高浓度Na NO2时形成的锈层较为疏松,使得锈层中Fe3O4含量逐渐减少。
[Abstract]:When weathering steel is exposed to the atmosphere, its surface can form a protective rust layer with good bonding with the matrix, so that it can be used directly in some environments without surface protection. Before the stable rust layer is formed, the surface of the steel will have the phenomenon of liquid rust hanging and dispersing, which will lead to environmental pollution and restrict its development. In order to solve this problem in the early 1960s, Japan first developed the stabilization treatment technology of rust layer on weathering steel surface, which can promote the transformation of rust layer from 纬 -Fe OOH to 伪 -Fe OOH, and shorten the forming time of stable rust layer. At present, the domestic technology is not mature, so the cost of research and development is relatively low. And it is widely used to stabilize the rust layer on the surface of weathering steel. It has remarkable economic benefit and engineering value. The main contents of the research on the stabilization technology of rust layer on weathering steel surface include materials which can promote the formation of homogeneous and dense stable rust layer on weathering steel surface as soon as possible (we call it. The selection of stabilizers, And the selection of organic coating materials used in surface stabilization treatment of weathering steel. In this paper, the selection of stabilizer for low cost, all-weather type mn Cu P weathering steel was studied. In this paper, X- ray diffraction and potentiodynamic polarization curves are used to simulate the dry / wet alternating experiments of atmospheric corrosion. The effects of concentrations of Cr2(SO4)3 and Na NO2 in coastal atmospheric environment on the stabilization of rust layer on the surface of mn Cu P weathering steel were studied by electrochemical impedance spectroscopy. The main work includes the following aspects: the simulation of Cr2(SO4)3 in coastal atmosphere has been studied. Effect of addition on corrosion behavior of mn Cu P weathering steel. The addition of Cr2(SO4)3 in coastal atmosphere simulated solution can obviously reduce the corrosion rate of mn Cu P steel and accelerate the stabilization of rust layer on the surface. However, the effect of Cr 2 so 4 so 4 + 3 on the corrosion behavior of mn Cu P steel has the phenomenon of concentration extremum. When the concentration of Cr2(SO4)3 in the simulated solution is 0.02 mass%, the corrosion weight of mn Cu P steel is the least and the steel is in a stable state. The effect of Na NO2 addition in simulated coastal atmosphere on the corrosion behavior of mn Cu P weathering steel is studied. The corrosion behavior of mn Cu P weathering steel is studied by 60 dry / wet tests. Alternating atmospheric corrosion experiments show that, The addition of Na NO2 in coastal atmospheric simulated solution can obviously reduce the corrosion rate of mn Cu P steel and accelerate the stabilization of surface rust layer. However, the higher Na NO2 concentration makes the corrosion rate of mn Cu P steel too small. It is not conducive to the formation of protective rust layer on steel surface as soon as possible. When the concentration of Na NO2 in the simulated solution is 0.005, the corrosion weight of Mn-Cu P steel is minimum and the corrosion becomes stable. In all simulated environments, the rust layer on the surface of Mn-Cu P steel is composed of 伪 -Fe OHH, 尾 -Fe OOH, 纬 -Fe OOH and Fe3O4. The presence of a small amount of Cr2(SO4)3 in the simulated solution inhibited the formation of 尾 -Fe OOH and promoted the formation of Fe3O4. However, the presence of more Cr2(SO4)3 inhibited the reduction of 尾 -Fe OOH to Fe3O4, and the presence of a small amount of Na NO2 promoted the formation of Fe3O4. However, the rusty layer formed at high concentration of Na NO2 was looser, and the content of Fe3O4 in rust layer decreased gradually.
【学位授予单位】：沈阳理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG174.4

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