Surface Finishing of Alumina Ceramics by Means of Abrasive Jet Machining

Abstract

Abrasive jet machining (AJM) is proposed as a new approach to surface finishing of structural ceramics. The effect of AJM on the material removal behavior of a commercially available alumina ceramic, and its effect on mechanical properties, was characterized and compared with identical material subjected to conventional finishing processes. Conventional grinding of the ceramic resulted in a surface that was dominated by intergranular fracture, whereas, during AJM, impact by the abrasives led to material removal in a manner resembling ductile behavior, and the resulting surface appearance was much smoother. A significant improvement in flexural strength was attained, compared with the strength of both the ground and lapped samples, because of an induced compressive residual stress.

Erosion of Dental Glass Infiltrated Aluminum Ceramics

“…At the same parameters, the effects of time and erodent size on the wear depth are not so prominent. The adaptation of all-ceramic crown with its abutment is critical in the clinic for it determines the long-term survival of a crown in practical use [5]. The ADA recommends that the discrepancy of metal crown is below 40 µm and 50-100 µm is acceptable for marginal discrepancy in clinical practice.…”

“…There is usually more infiltrated glass left on the surface of ceramics, which has been removed routinely by sandblasting to create a micro retentive surface for veneer porcelains. Sandblasting on ceramic restorations has the possibility to remove significant amounts of material and might affect the strength of the ceramic restoration or the clinical fit with the prepared abutments (ADA: the discrepancy is below 40 µm) [5]. Quantitative data are still unavailable on the wear depth loss and surface roughness variation of dental glass-infiltrated ceramics after sandblasting.…”