نگاهي علمي مطالعات تطبيقي و ساختاري به نمونه اي از هنر پيكره سازي تزييني در آثار فلزي دوره ي ايلامي

Scientific Studies on the One of the Decorative Figurines in the Metal Objects of Elamite Period

مبادلات فرهنگي بين امپراتوري ايلام و بين‌النهرين موجب خلق آثار هنري مشابه، به‌خصوص در هنر پيكره‌سازي شده است. در بسياري از آثار اين دوره، نشانه‌ي احترام به‌خداي بزرگتر در اشكال مختلف پيكره‌ها مشهود است. از جمله آثار ارزشمند دوره‌ي ايلامي مي‌توان به كلاهخود مفرغي متعلق به موزه‌ي رضا عباسي تهران با سه پيكره‌ي تزييني روي آن اشاره نمود. اين اثر، مشابه با كلاهخود موجود در موزه‌ي متروپوليتن نيويورك بوده، از مجموعه‌ي خصوصي خريداري و به موزه منتقل شده و تاكنون مطالعه‌ي و پژوهش خاص و منسجمي در مورد آن انجام نگرفته است. با توجه به‌شواهد ظاهري، فرضيه‌ي استفاده از آلياژي متفاوت با بدنه‌ي كلاهخود به‌عنوان پوشش فلزي سطح پيكره‌ها و گُل‌ميخ‌هاي اطراف كلاهخود و استفاده از ماده‌ي آلي در بدنه‌ي پيكره‌هاي تزئيني مطرح بوده است. بر اين‌اساس مطالعه‌اي علمي با استفاده از روش‌هاي ميكروسكوپ نوري و روبش الكترون مجهز به سيستم تجزيه‌ي عنصري (SEM-EDX) و با هدف تجزيه‌وتحليل اين اثر فاخر به‌منظور پاسخ‌گويي به سؤالات مطرح در زمينه‌ي دوره‌ي تاريخي تكنيك به‌كار برده شده در ساخت اين اثر و مواد مورد استفاده در آن صورت‌گرفته است. براساس مطالعات تطبيقي صورت‌گرفته، كلاهخود احتمالاً متعلق به دوره‌ي ايلام مياني است. بررسي‌هاي علمي انجام شده نشان مي‌دهد بدنه‌ي اصلي كلاهخود از برنز قلع و به‌روش ريخته‌گري و چكش‌كاري ساخته شده است. در ساخت بدنه‌ي پيكره‌ها از ماده‌ي قير طبيعي استفاده شده كه به‌مرور زمان فرسوده شده است. نتايج پژوهش نشان مي‌دهد بدنه‌ي ساخته شده از مواد آلي پيكره‌ها با فلز نقره‌مطلا پوشيده شده و به‌مرور زمان دچار خوردگي شده‌اند. همچنين تصاوير ميكروسكوپي نشان‌دهنده‌ي به‌كارگيري ليف طلا با فن حرارت‌دهي در روند پوشش‌دهي نقره‌ي به‌كار رفته بر سطح پيكره‌ها بوده است و در اين فرايند حرارتي، انتشار طلا در لايه‌ي نقره صورت‌گرفته است. گل‌ميخ‌هاي تزييني دورتادور كلاهخود در برخي قسمت‌ها جلاي فلزي داشته، اما در بسياري موارد پوشيده از محصولات خوردگي سبز رنگ مس بوده و از آلياژ نقره با مقاديري مس ساخته شده‌اند.

Cultural exchanges between the Empire Elam and Mesopotamia led to create similar masterpieces of art, especially in art of sculpture. In many works of arts of this period, a sign of respect to God Elder has been shown in the various forms of Sculpture. One of the valuable objects of Elamite period is a bronze helmet with three small decorative figures on the front side that belongs to the Reza Abbasi Museum. This object is similar to the famous helmet that is storef in the Metropolitan Museum of New York. This bronze helmet is purchased from a private collection and transferred to the museum. The surface evidence indicates that silver is used in the manufacture of these figurines. Surface of applied metal in this figurine is darkening that caused by corrosion and also remaining evidence of the golden layer can be seen in small areas. No specific and coherent research has yet been done about this object. According to this article, a scientific study has been done by using optical and scanning electron microscopy with elemental analysis system (SEM-EDX) that its aim is analyzing this special object to study the techniques of production and material which is applied in making of this object. Comparative studies have shown that the helmet dated back to the middle Elamite period. Worship and prayer mode can be seen in three small decorative figurines on this helmet. Middle figurine has large eyes that introduces a state of superhuman power. In two hands of longer figurine as a God Elamite is a vessel that has two threads of water running from its sides as the water of life which is the symbol of life. On either side of head of middle figurine, long braided hair can be seen which is common only during the middle Elamite period. Two smaller statues are wearing clothes with horizontal folds to be drawn on the ground and there are ornaments like fish scales on a longer figurine clothes that show art aspect of the middle Elamite period. Former elemental analysis using X-ray fluorescence spectroscopy (XRF) on the main side of helmet shows that the main body of this helmet is made of tin bronze with casting and Hammering methods. Scientific studies with energy-dispersive X-ray spectroscopy (EDX) that is an analytical technique used for the elemental analysis or chemical characterization of a sample shows that bitumen used in the body of three small decorative figurines. Based on the results of distribution of gold and silver elements by EDX, this organic material that is decomposed during the time, covered with gilded silver metal. In mercury gilding or fire gilding with use of mercury as an amalgam or glue for coverage by gold leaf, heat is used for removing mercury but the results of elemental analysis layers on the organic material of main body of sculptures with energy-dispersive X-ray spectroscopy (EDX), has not shown residue of mercury. So, amalgam method is not used to create gold coating on the surface of silver. Instead of it, scanning electron microscopy images represents the application of gold leaf with heating method on the surface of silver coating of three small decorative figurines and the result of this thermal process is diffusion of gold in silver layer. In this case, the sheet or foil directly used onto the surface and mechanical connections are heated. So, diffusion bond of gold and substrate connection is established. Internal diffusion in scanning electron microscopy has shown good connection between the gold and metal background and gold loss in many parts may be due to the weakening of structure of silver caused by corrosion. Decorative nails around his helmet in some areas have metallic luster but in many cases, covered with green copper corrosion products and is made of silver alloy with some copper.