One-Step Combustion Method of HPA Preparation for LED Applications

Abstract

Alumina (Al₂O₃) is widely used in a variety of applications because it has superior physical and chemical properties which are high heat resistance, excellent electrical isolation, abrasion resistance, and high corrosion resistance. Generally, alumina is manufactured with a purity of 99.6–99.9% mainly by the Bayer process with bauxite as the starting material. It is used in refractory products, spark plugs, IC substrates, and so on. High-purity alumina (HPA), which has a purity of more than 99.99% and has a uniform fine particle, is widely used in translucent tubes for high-pressure sodium lamps, single crystal materials such as sapphires for watch covers, high-strength ceramic tools, abrasives for magnetic tape, and the like. In recent years, the demand for high-purity alumina has been expanding in fields that are expected to show a high growth rate e.g., display materials, energy, automobiles, semiconductors, and computers. There are several complicated processes reported in literature to produce single phase α-HPA, which consumes more energy, and power and are very costly. In this paper, we report the preparation of nano-α alumina powders with a purity of 3N (99.9%) by a simple, economical, and faster method i.e., one-step auto combustion method. To obtain single phase α-alumina, the calcination temperature required is 1200°C but, in our work, we achieved single phase α-alumina at 500°C temperature by one-step auto combustion method. The as-prepared HPA is characterized through XRD, BET surface area, SEM and ICP, TGA, and LIBS to test for purity and its application in LED fabrication.