Journal of Sol-Gel Science and Technology 13, 753–756 (1998) c  1998 Kluwer Academic Publishers. Manufactured in The Netherlands. Inhibition of Pb-Leaching from Lead Crystal Glass by Coating with Films Prepared by the Sol-Gel Method A.A. AHMED, I.M. YOUSSOF AND A.F. ABBAS Glass Research Laboratory, National Research Center, Dokki, Cairo 12622, Egypt O. ABOU ELEINEN Glass Research Laboratory, National Research Center, Dokki, Cairo 12622, Egypt; and Petroleum Applications Department, Petroleum Research Institute, Nasr City, Cairo, Egypt Abstract. The chemical durability of lead glass tumblers (24% PbO) in a 4% (v/v) acetic acid solution before and after coating with sol-gel derived SiO 2 films was assessed to determine the extent of reduction in Pb-leaching that can be achieved. It was found that by coating the internal surface of the glass tumblers with 1 ml of 10% TEOS solutions at 100 ◦ C and densifying the coating formed at 500 ◦ C for 1 h, it was possible to reduce Pb-leaching to about one quarter of that of the uncoated glass. Keywords: lead crystal glass, sol-gel coating, lead leaching, durability improvement Introduction Lead oxide is used as an essential constituent in many types of glass. Lead crystal glass is probably the most commonly known lead containing glass. Lead oxide was used in this particular type of glass to cause a substantial increase in its refractive index and light dispersion giving the glass a notable brilliance. The chemical resistance of lead crystal glass toward at- tack by aqueous solutions is an important property [1]. A high degree of chemical stability, including no visible alteration, is required. Recently, the chemical durability of lead crystal glass has become a top pri- ority subject for lead crystal glass manufacturers, users and standardization organizations. This is due to the toxic nature of the lead that migrates from lead crystal glassware, in conjunction with other cations, during their contact with food and drinks. Recent medical reports show that excessive exposure to lead and its accumulation in the human body can lead to kidney problems, raised blood pressure, changes in the ner- vous system, birth defects, anemia and death in severe cases [2]. This has led standards organizations to set limits for the allowable levels of lead release during standard testing conditions from lead crystal glassware intended for use in the preparation, storing or serving of food and drinks. The maximum permissible limits of lead release were revised downward to about one tenth of their previous values during the last 10 years [3]. Although the levels of lead release from com- mercially available lead crystal glassware designed to be used in contact with food and drinks were already low, they now have to be substantially reduced [4]. This necessitates either elimination of lead oxide en- tirely from lead crystal glass compositions or treatment of the surface of the glassware that will be in contact with food and drinks so as to substantially improve its chemical resistance. One of the possible treatments is to coat the glass surface with a sol-gel derived silica film that is known to possess extremely high chemi- cal resistance to aqueous solutions of pH values lower than 9 [5]. In this work, the preliminary results of a study of the chemical durability of a commercially available lead crystal glass tumbler (24% PbO) before and after coat- ing with sol-gel derived silica glass film are reported. This study was carried out to determine the extent of improvement of the chemical durability, i.e., the extent of reduction in lead leaching that can be achieved by such coating.