Evolution and Evaluation of Aesthetic Properties in Weathering Steel Accelerated Patinas: The Role of Lepidocrocite

Metals

Sagrario Martínez-Ramírez¹  Ana Crespo¹  Iván Díaz²  Emilio Cano²  Gloria Pérez³  José A. Jiménez⁴  Irene Llorente⁵ 

[1] Departamento de Espectroscopía Nuclear, Vibracional y de Medios Desordenados, Instituto de Estructura de la Materia, Consejo Superior de Investigaciones Científicas (IEM, CSIC), 28006 Madrid, Spain;Departamento de Ingeniería de Superficie, Corrosión y Durabilidad, Centro Nacional de Investigaciones Metalúrgicas, Consejo Superior de Investigaciones Científicas (CENIM, CSIC), 28040 Madrid, Spain;Departamento de Materiales, Instituto de Ciencias de la Construcción Eduardo Torroja, Consejo Superior de Investigaciones Científicas (IETcc, CSIC), 28033 Madrid, Spain;Departamento de Metalurgia Física, Centro Nacional de Investigaciones Metalúrgicas, Consejo Superior de Investigaciones Científicas (CENIM, CSIC), 28040 Madrid, Spain;Laboratorio de Difracción de Rayos X, Centro Nacional de Investigaciones Metalúrgicas, Consejo Superior de Investigaciones Científicas (CENIM, CSIC), 28040 Madrid, Spain;

关键词: weathering steel;    sculpture;    corrosion;    color;    contemporary art;    conservation-restoration;   

DOI  :  10.3390/met12060977

来源: DOAJ

【 摘 要 】

Weathering steels are widely used in civil engineering, architecture and contemporary art due to their mechanical properties, their enhanced resistance to atmospheric corrosion as well as their aesthetic properties. Artists and blacksmiths often apply chemical treatments to obtain the appealing colors of a patina in a shorter period of time. However, the development of an accelerated patina may have an effect on the final appearance and color of the surface. With the aim of evaluating differences in color and studying the evolution of the surface, eight accelerated patinas were made and exposed to the atmosphere for periods of time of up to 24 months and were compared to a natural patina. The characterization studies showed the presence of lepidocrocite on the surface. A close inspection of the X-ray diffraction patterns showed the displacement of the (020) lepidocrocite reflection and asymmetric broadening of selective lines of this phase that were associated to stacking and twins faults, respectively. These faults decrease with the exposure time and are related to a maximum at 630 nm in the reflectance spectrum and the stabilization of the b* coordinate (yellow color). The colors of the accelerated patinas differ from the natural patina at short exposure times. However, they tend to converge at longer exposure times.

【 授权许可】

Unknown