Highly Transparent Pure Alumina Fabricated by High‐Pressure Spark Plasma Sintering

Abstract

Highly transparent pure alumina with an average grain size of 200 nm was fabricated by means of high‐pressure spark plasma sintering. The alumina sintered either at 950° or at 1000°C for 10 min under an applied pressure of 500 MPa had an in‐line transmission of about 64% for a wavelength of 645 nm. The application of high pressure allowed to obtain highly transparent full dense alumina at low temperatures with no considerable grain growth.