Flame cleaning of historic wrought iron: practitioner methods and their impact on oxide morphologies and post-treatment corrosion rates
Flame cleaning of historic wrought iron: practitioner methods and their impact on oxide morphologies and post-treatment corrosion rates
复制标题
历史锻铁的火焰清洗：实践方法及其对氧化物形态和后处理腐蚀速率的影响
DOI：
--
复制
发表时间：
2019
期刊：
影响因子：
--
通讯作者：
J. Thunberg
中科院分区：
文献类型：
--
作者：
N. Emmerson;D. Watkinson;J. Thunberg
火焰清洗后再刷线是锻铁的一种常见处理方法；火焰燃烧现有的涂层并剥落氧化物，而刷线去除任何碎屑，产生用于重新涂层的良好表面。虽然经常使用，但人们对处理对衬底材料的影响及其处理后的腐蚀率知之甚少。本研究报告了三名从业人员清洗锻铁火焰的扫描电子显微镜、背散射电子成像(SEM-BEI)和氧耗腐蚀速率测试。经过两名从业人员处理的锻铁样品的腐蚀速度比未经清洗的对照样品快4倍。由一名从业人员清洗的样品没有显示出腐蚀速度的增加。火炬燃料类型和由铁获得的温度被确定为可能导致腐蚀率差异的参数。对比处理样品和未处理样品的氧化物形态，发现火焰清洗后出现了广泛的开裂和碎裂。这为氧气和水进入金属核心以支持腐蚀提供了多种途径。这些数据同时对火焰清洁的伦理提出了质疑，并提供了证据表明存在一种“安全”的方法，促使人们对这种流行的治疗方法进行进一步的研究。
Flame cleaning followed by wire brushing is a common treatment for wrought iron; the flame combusts existing coatings and spalls oxides while wire brushing removes any debris, producing a sound surface for recoating. Although frequently applied, little is known about the effects of the treatment on the substrate material and its post-treatment corrosion rate. This study reports scanning electron microscope backscattered electron imaging (SEM-BEI) and oxygen consumption corrosion rate testing of wrought iron flame cleaned by three practitioners. Wrought iron samples treated by two practitioners corrode up to 4 times faster than uncleaned control samples. Samples cleaned by one practitioner exhibit no increase in corrosion rate. Torch fuel type and temperature attained by the iron are identified as parameters potentially contributing to differences in corrosion rates. Comparing oxide morphology of treated and untreated samples reveals extensive cracking and fragmentation following flame cleaning. This offers multiple pathways for ingress of oxygen and water to the metal core to support corrosion. This data simultaneously calls into question the ethics of flame cleaning and offers evidence that a ‘safe’ method exists, prompting further research into this popular treatment.