Frequently Asked Questions
Mechanical testing provides information on the quality or integrity of components. Conventionally, bend, shear and tensile tests define static performance, and the load needed to cause failure is taken to characterise bond strength.
There is no simple answer to the question of what specimen geometry or test is best. Standards are lacking in the strength testing of ceramic joints, and care should be taken when comparing test results from different studies. Best practice is to use whichever configuration most closely replicates the environment of the component in service.
Because of the developmental nature of much of the work on this subject, a wide variety of techniques has been used to measure strength values of ceramic joints.
Bond strength values depend on the testing technique and size of specimen chosen. For brittle materials, bend test values tend to be 10-50% higher than tensile test values. Defects such as pores, cracks, unbonded regions and inclusions all act as stress concentrators and decrease the recorded strength.