Analytical and microstructural approach to the study of historical ultra-high carbon (UHC) steel plaques belong to the Malek National Library and Museum Institution, Iran ☆ Mohammad Mortazavi a, ⁎, Davoud Agha-Aligol b a Faculty of Art Entrepreneurship and Tourism, Art University of Isfahan, P. O. Box 1744, Isfahan, Iran b Van de Graaff laboratory, Physics and Accelerators Research School, Nuclear Science & Technology Research Institute (NSTRI), P. O. Box 11365-3486, Tehran, Iran abstract article info Article history: Received 14 January 2016 Received in revised form 10 May 2016 Accepted 11 May 2016 Available online 13 May 2016 A number of steel plaques in Iran belong to Safavid period (17th century) were examined for their chemical com- position and microstructure. The artefacts were analyzed using micro-PIXE, SEM-EDS and reflected light micros- copy (OM). According to SEM-EDS and micro-PIXE analyses, it was revealed that the plaques were made of mostly pure iron (approximately 99 wt%). Presence of trace amounts of manganese, sulfur, chromium, silicon, ti- tanium and potassium were identified in the plaques. Metallographic investigation showed that the plaques were made of hypereutectoid steel with a microstructure consisting of spherical particles of carbide in the ferrite and pearlite background. Moreover, the use of ultra-high carbon (UHC) steel with microstructure of pearlite ma- trix and needle-like Widmanstätten cementite was identified in one plaque. These features showed that Safavid plaques have been made of crucible steel. In addition, it demonstrated that complicated forging/heating cycles have been used for manufacturing of these openwork steel plaques. It was also revealed that in addition to arms and armors, crucible steel has served as an everyday work material in Safavid period in Iran. © 2016 Elsevier Inc. All rights reserved. Keywords: Crucible steel Safavid openwork plaque Iran Micro-PIXE SEM-EDS Metallography 1. Introduction Safavid period in Iran (16th–18th century) is famous for flourishing and developing of metalwork [1]. A large number of masterpieces with exceptional quality which were made of copper, bronze and iron have been remained form this time [2–4]. Despite the presence of lots of metal artifacts, our knowledge about Safavid metalwork is limited, a number of books and papers have been published in this regard, but there are few investigations of material and techniques. New styles in metalwork appeared in Safavid period (17th century) including openwork steel plaques some of which are preserved in word wide museums. These unique steel plaques are well-known for their airily flowing calligraphy and impressive designs [5,6]. Nonetheless, sci- entific investigation of these artifacts has not been done so far. Surface analyses of two rectangular pierced-steel plaques (No. 28 and 29) in Freer Gallery of Art are the only samples in this case. X-ray Fluorescence (XRF) analyses did not indicate the presence of elements other than iron in both plaques [4]. However, there is not any integrated analytical investigation of such outstanding masterworks. Accordingly, this re- search is concerned with metallurgical examination of eight Safavid steel plaques belong to Malek National Library and Museum Institution, Tehran, Iran. Steel plaques have been studies for their chemical compo- sition and microstructure. Manufacturing techniques of these plaques have been characterized using SEM-EDS analysis and optical microscopy. 2. Material and methods Eight Safavid pierced-steel plaques (late 17th century) belong to Malek National Library and Museum Institution, Tehran, Iran, have been selected for these studies (Fig. 1). The plaques are made of a thin sheet of steel. Each plaque is done in openwork bearing delicate spiral- ing arabesques and elegant inscriptions in thuluth or nastaliq scripts. Samples from each plaque were taken with jeweler's saw so that they cover its entire thickness. The samples were embedded in Buehler epoxy resin and polished by silicon carbide abrasive paper (up to 3000 grit). The final polish was performed with 1 μm diamond paste. Proton Induced X-ray Emission microanalysis (Micro-PIXE) was used to analyze the alloy composition of the samples. The Micro-PIXE analyses were performed using the 3 MV Van de Graaff accelerator of Nuclear Science & Technology Research Institute with a scanning proton microprobe manufactured by Oxford Instruments [7]. Samples were Materials Characterization 118 (2016) 159–166 ☆ This study has been carried out in the framework of research project No. 933/2, financed by the Research Office of the Art University of Isfahan, Iran in 2014–2015 (contract No. 93-20/1363). ⁎ Corresponding author. E-mail addresses: m.mortazavi@live.com (M. Mortazavi), d_aligol@yahoo.com (D. Agha-Aligol). http://dx.doi.org/10.1016/j.matchar.2016.05.008 1044-5803/© 2016 Elsevier Inc. All rights reserved. Contents lists available at ScienceDirect Materials Characterization journal homepage: www.elsevier.com/locate/matchar