Optical Properties of Infiltrated High Porosity Alumina

Objectives: 1. To fabricate a novel ceramic matrix composite
2. To determine the effects of the use of porogen and sintering temperature on the optical properties of the infiltrated porous alumina composite.
Methods: Alumina powder: (A16SG, Almatis Inc., Leetsdale, PA) was mixed with a porogen (0%, 10%, 20% wt) and pressed to fabricate a cylindrical alumina block. After the blocks were partially sintered at 1050 °C for 2 hours, they were sectioned to produce 2 mm-thick discs. The polished discs were randomly divided into 18 groups (n=10/gp) according to sintering temperature (1250, 1350, and 1550 °C). The sintered porous discs were silane infiltrated of and then each disc was dried in a vacuum oven at 90 °C for 24 hours. Resin solution was prepared by mixing Triethylene glycol dimethacrylate (TEGDMA) with Urethane dimethacrylate (UDMA). After infiltration with resin the discs were heat cured under pressure. The density was measured. The optical properties including refractive index, contrast ratio, transparency parameter, and visible light transmission were measured using spectrophotometer (Color i7, X-rite Inc., Grand Rapid, MI). Analysis of variance (ANOVA) followed by Tukey’s multiple-comparison test (p < 0.05) was used to analyze the density and optical properties using R program.
Results: The average and standard deviation of % density, refractive index, light transmission, transparent parameter, and contrast ratio of different alumina discs are shown in Table 1.
Conclusions: Increasing the porogen content during alumina disc preparation and increasing sintering temperature significantly improved optical properties.