Journal of Advanced Ceramics 2014, 3(4): 332–338 ISSN 2226-4108 DOI: 10.1007/s40145-014-0125-x CN 10-1154/TQ Research Article Role of MgF 2 addition on high energy ball milled kalsilite: Implementation as dental porcelain with low temperature frit Pattem Hemanth KUMAR a,* , Abhinav SRIVASTAVA a , Vijay KUMAR a , Nandini JAISWAL a , Pradeep KUMAR b , Vinay Kumar SINGH a a Department of Ceramic Engineering, Indian Institute of Technology (BHU), Varanasi, India b Department of Chemical Engineering, Indian Institute of Technology (BHU), Varanasi, India Received: June 17, 2014; Revised: August 11, 2014; Accepted: August 18, 2014 ©The Author(s) 2014. This article is published with open access at Springerlink.com Abstract: Porcelain fused to metal (PFM) has received great attention over the last few years due to its importance in the dentistry. Kalsilite (K 2 O·Al 2 O 3 ·SiO 2 ) is a high thermal expansion porcelain, suitable for bonding to metals. However, kalsilite is a metastable phase which gets converted into crystalline leucite upon heating. In the current work feasibility of developing stable kalsilite phase, dispersion of MgF 2 in it as an additive and using mechanochemical synthesis are studied. Micro fine dental material has been formulated by mixing prepared kalsilite with low temperature frit (LTF) in different ratio. The crystalline phases evolved in fired powders are characterized by powder X-ray diffraction (XRD) technique. Kalsilite with different ratio of LTF has been cold pressed and heat treated to examine its coefficient of thermal expansion (CTE), flexural strength, apparent porosity (AP), bulk density (BD) and microstructure. Results indicate that MgF 2 addition and high milling duration help in kalsilite stabilization. Temperature also plays an important role in this stabilization, and at 1100 ℃ single phase kalsilite formation is observed. Present outcomes demonstrate that it is easily possible to synthesize a stable single phase kalsilite with desirable properties. Keywords: kalsilite; porcelain fused to metal (PFM); dental ceramic; mechanochemical synthesis; thermal expansion; X-ray diffraction (XRD) 1 Introduction Ceramic materials have been widely used in porcelain fused to metal (PFM) and all ceramic restoration systems over the last decade. They typically have high coefficient of thermal expansion (CTE) and high flexural strength. Kalsilite (KAlSiO 4 ) mineral has a network of tetrahedral Si and Al elements with charge balancing alkali metal ions [1]. CTE of kalsilite is 16×10 6 (℃) 1 [2]. Kalsilite is a significant constituent in PFM and ceramic restoration systems [3]. It is used as the precursor of leucite [4]. Becerro et al. [4] have previously reported that kalsilite being a high thermal expansion ceramic, is suitable for bonding to metals. Kalsilite however crystallizes as a metastable phase when synthesizing leucite [5,6]. Kalsilite has been synthesized previously by various techniques such as hydrothermal method [7], sol–gel method [8,9] and solid-state method [10,11]. Accompanying with other synthesis methods, mechanochemical process is economical and suitable to prepare pure materials with a micro fine particle size [1214]. This synthesis involves chemical reactions of solids under the action of mechanical forces. Driving  * Corresponding author. E-mail: phemanth111@gmail.com