1336 Bioceramics

The general field of bioceramics has developed rapidly. Beginning in the 1970s it was established [16, 17] that several high-purity ceramics offered long-term bio-compatibility. The desirable aspects of ceramics for biological applications stems from their high hardness, corrosion resistance, good lubricity, and low friction.

Strength (MPa)

FIGURE 13.20 Correlation between stress-wave factor and retained strength of alu-mina-mullite and clad-bonded SiC hot-gas filters.

FIGURE 13.22 Photograph of ceramic head used in conjunction with metal shaft as part of a hip joint replacement.

Four ceramic materials are presently used. These are alumina, partially stabilized zirconia, P-tricalcium phosphate, and calcium hydroxyapatite. Of these, alumina and zirconia are used for prosthetic applications including hip joint replacements [6]. Figure 13.22 shows a photograph of a typical ceramic ball used as part of an artificial hip joint replacement.

From an NDE point of view, it is crucial to detect potential failure-causing internal defects as well as any machining damage done to the surface of the ball. The technologies discussed previously are applicable.

0 0

Post a comment