Ceramics for medical devices

Ceramics are used where metal reaches its limits: wear resistance, biocompatibility and electrical insulation. In joint replacement, bearing couples of alumina and alumina-toughened zirconia are common because they generate far less wear debris than metal-on-polyethylene — and wear debris is a leading cause of revision. In dental technology zirconia dominates; in electromedicine ceramics serve as insulators and feedthroughs.

The price is brittleness. Ceramics do not forgive tensile stress peaks, and what would be a dent in metal is a fracture here. In design terms that means no sharp internal corners, compressive rather than tensile loading, and careful design of joints. In manufacturing terms it means that after sintering only grinding remains — changes to the green body are cheap, changes afterwards are expensive.

For buyers, grain size, density and purity of the starting powder matter, as do the sintering schedule and surface finish. And the question of inspection: internal defects in ceramics are hard to find. Where they are safety-relevant, non-destructive testing and statistical assurance via Weibull parameters belong in the scope of supply.