Residual Stress Causes Ceramic Plate to Crack
View crack detail. My husband is known for his creative special effects, usually involving food, like the time he grilled eggplant slices and formed them into stacks vaguely reminiscent of that famous leaning tower in Italy. Just as he sliced into his own architectural wonder, a live beetle scuttled out from under his stack, which seemed like a really interesting, if slightly repulsive, way to work protein into the menu. The other night, however, he truly outdid himself. As he was taking one of our Waechtersbach ceramic dinner plates from the cupboard, he heard a cracking noise emanating from it. Upon inspection, he observed a radial crack about 3 inches in length.
The question is whether the notch (see crack detail) was a crack initiation site, or whether the notch area simply flaked off during the event, which I believe was caused by residual stress in the ceramic, most likely improper annealing. Most engineering students learn early on why when you cool things down, you need to cool them down slowly. If residual stress is indeed the culprint, then the mere act of my husband picking up the plate and taking it out of a cool closet and in proximity of a warm oven may have providede enough energy to get the crack to propogate. Either way, with this plate and a busted pewter serving fork that succumbed to bending stresses recently, I now have a perfectly matched Made by Monkeys dinnerware set! View broken fork