CERAMICS INTERNATIONAL Available online at www.sciencedirect.com Ceramics International 40 (2014) 11299–11309 Effects of sintering temperature and initial compaction load on alpha-alumina membrane support quality Sanjib Barma, Bishnupada Mandal n Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, India Received 26 January 2014; received in revised form 24 March 2014; accepted 24 March 2014 Available online 5 April 2014 Abstract This work reports the effect of sintering temperature and compaction load on the quality of α-alumina (  particle size o1 mm) membrane support for dry compaction method. We analyzed the membrane synthesis process to get good quality membrane support in a more economical way by reducing the holding time (4 h) at different sintering temperatures. The effect of initial compaction load on porosity, pore size, flexural strength and shrinkage during synthesis of α-alumina support at various sintering temperatures was investigated. It was found that at 1500 1C sintering temperature and 350 kN compaction load, the support exhibited least porosity of  1.4% and least pore sizes of  67 nm, whereas at 1200 1C and 50 kN compaction load, the support showed the highest porosity of  55% and highest pore size of  505 nm.Maximum flexural strength of  200 MPa was obtained for the support synthesized at 1500 1C sintering temperature and 350 kN load. & 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved. Keywords: A. Sintering; α-alumina; Compaction load; Pore size 1. Introduction Inorganic ceramic membranes have attracted considerable attention during last decades due to their superior characteristics such as excellent mechanical strength, chemical resistance, unaffected by high temperature environment, etc. over other types of membranes. Inorganic membranes are vastly used in several process industries like water- treatment, pigment, food, paper-making, chemical and pharmaceutical. Inorganic mem- branes have also received considerable attention for gas separa- tion application. The gaseous flux in these membranes is directly proportional to the applied pressure as opposed to dense metallic membranes where the flux is proportional to the square root of the pressure [1]. Therefore, inorganic micro-porous membranes are advantageous as they can operate at comparatively higher pressures. Design and fabrication of porous ceramic membrane requires several layers of different materials. The foundation of the structure is a thick, macro-porous support that carries one or more intermediate as well as selective top layers of other ceramic materials [2]. A defect on the surface of the selective top layer significantly decreases the selectivity. Since only the top layer has separating capacities, the support must have an excellent surface morphology for deposition of subsequent layers but retain sufficient permeability. A ceramic membrane support is com- monly prepared by shaping a powder into a green body and then by sintering the obtained green body into the final membrane support. In case of green bodies' processing, it is common to use organic binders. These organic binders are eliminated during the heat treatment step. Alumina (α-Al 2 O 3 ) is commonly used for synthesis of ceramic substrate. α-alumina support of small pore size is normally prepared by sintering compacted α-alumina powder at higher temperature. Properties (such as pore size, porosity, density, particle size, etc.) of the membrane support change significantly under processing conditions like sintering temperature, control of heating and cooling rate, sintering time, etc. [3]. Effects of sintering on properties of the alumina compacts have been studied in the literature [4–9]. Some of these studies reported that mean pore sizes of compacts with the increase in www.elsevier.com/locate/ceramint http://dx.doi.org/10.1016/j.ceramint.2014.03.134 0272-8842/& 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved. n Corresponding author. Tel.: þ91 361 258 2256 (office), þ91 2584265 (residence); fax: þ 91 361 2582291. E-mail address: bpmandal@iitg.ernet.in (B. Mandal).