Effect of processing variables on texture development in a mica-based glass-ceramic

✍ Scribed by Denry, I. L. ;Baranta, G. ;Holloway, J. A. ;Gupta, P. K.

• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: English
• Weight: 422 KB
• Volume: 64B
• Category: Article
• ISSN: 0021-9304
• DOI: 10.1002/jbm.b.10514

✦ Synopsis

Abstract

The purpose of this study was primarily to determine the feasibility of heat‐pressing a mica‐based glass–ceramic with the use of commercially available dental equipment, and secondly to evaluate the effect of various processing variables on the degree of crystal alignment in the pressed glass–ceramic. The hypotheses were that the mica‐based glass–ceramic could be successfully heat‐pressed and that some degree of crystal orientation would be obtained, depending on the processing variables. The glass composition was melted at 1400 °C for 2 h and cast into 12 × 60‐mm rods. Ingots (10 × 12 mm) were cut from the glass rods, heat treated, and heat‐pressed under various conditions. The microstructure of the pressed specimens was investigated by SEM and compared to that of heat‐treated controls. The length of Vickers‐induced cracks was measured on heat‐pressed specimens and heat‐treated controls. The results showed that mica‐based glass‐ceramics could be successfully pressed with the use of commercially available dental equipment. The resulting degree of crystal alignment (texture) along the direction of pressing varied between 35 ± 6 and 79 ± 6. There was a linear relationship between the degree of texture and the apparent aspect ratio of the mica platelets. A significant decrease in the length of the Vickers‐induced cracks in the direction perpendicular to pressing was observed, associated with an increase in length in the direction of pressing. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 64B: 70–77, 2002