Analytical Study and Conservation of New Kingdom Period Pottery Jars from Saqqara Excavation, Egypt Mohamed Moustafa Ibrahim 1,a , Hamdy Mohamed Mohamed 1,b* 1 Conservation Dept, Faculty of Archaeology, Cairo University, Egypt a mmmi228@yahoo.com, b* hamdyaldeeb11@yahoo.com Keywords: Pottery, deterioration, black spots, digital microscope, XRD, SEM-EDX, conservation. Abstract. Ancient archaeological sites contain numerous pottery objects that suffered from different deterioration factors. This study aims to use different analytical methods to study the chemical and mineralogical composition and identification of deterioration aspects of some ancient Egyptian pottery jars from Saqqara excavation. Thus, to explain the deterioration factors' mechanisms and apply the proper conservation methods to the deteriorated pottery jars. AutoCAD, digital microscope, scanning electron microscope (SEM-EDX), and x-ray diffraction (XRD) were used to clarify the preservation states of pottery jars. The results of the investigation revealed that the selected jars suffered from different cracks, salts crystallization, some surface black spots, separation of the slip layer, and heterogeneity in the grains size. XRD analysis revealed that quartz, diopside, illite, muscovite, orthoclase, anorthite, and hematite are the main components of the jars. SEM-EDX analysis showed high concentrations of chlorides and sulfate salts, besides the presence of manganese oxide. Different treatments were performed for the pottery jars include mechanical and chemical cleaning. Additionally, the completion process was done by using a mixture of dental gypsum with grog. Moreover, the consolidation process was achieved by using paraloid B-72. 1. Introduction This study focuses on the examination and conservation of various pottery jars. During the season of 2019 at the Saqqara excavation site of the Faculty of Archeology, Cairo University, several pottery objects were discovered and it belongs to the new kingdom period in Egypt. Pottery is the most common artifact recovered through excavation [1]. The new kingdom was a period of general prosperity, and this was reflected in pottery. The pottery is very well made in this period, particularly those pieces made on the potter’s wheel. Molds were also used as a construction method for making vessels [2]. The surfaces of the new kingdom pots were treated in many ways. They could be simply smoothed while the clay was still wet or a slip layer is added to the surface of pots then burnished [3]. After completing the formation of the pots, a red slip layer is applied to the surface to cover any defects caused by the making of the pottery objects. The abundance of various sources of humidity, especially groundwater, finally leads to some chemical and mineralogical transformations [4]. Water from various sources is considered the basic damage factor of artifacts, additionally its fast role in dissolving the soluble ingredients [5]. The pottery artifacts buried in soil are severely deteriorated because of soil pressure, chemical deterioration, and the presence of salts [6]. Water spread into the objects is considered the main responsible for its deterioration, particularly for porous materials [7]. The humidity can migrate into the artifact's body, dependent on whether it is in the liquid or vapor state. Additionally, the transformation of dampness including a variety of mechanisms, such as absorption, vaporization, spreading, and capillarity as well as the surface tenseness of the liquid are shown [8]. The porosity of the pottery has a strong effect on its physical and mechanical properties. Extremely porous materials have high water absorption capacity and less stress-resistant as well as more susceptible to salt attack [9]. The salt blends are often related to salt weathering and often dry at high temperatures. The crystallization of the salt depends on the penetration of moisture into the body of artifacts [10]. Salts can move through pores only when dissolved in water [11]. Pores of pottery can also be damaged due to the presence of soluble salts inside the body itself, where the salts dissolve and recrystallize. Crystallization of the salts leads to Advanced Materials Research Submitted: 2020-07-07 ISSN: 1662-8985, Vol. 1167, pp 101-113 Revised: 2021-08-14 © 2021 Trans Tech Publications Ltd, Switzerland Accepted: 2021-08-16 Online: 2021-11-09 All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications Ltd, www.scientific.net. (#572007532-28/10/21,15:57:06)