Thermal expansion coefficient of titanium casting

A reliable measurement of the thermal expansion coefficient (alpha) value i s required to achieve a positive thermal mismatch between metal and porcela in for porcelain-fused to metal crowns. Heating rate and specimen condition s may significantly influence the alpha value and the effects of these fact ors were studied. Commercially pure cast titanium rods,'as cast' and sandbl asted, were heated at various conditions. According to this study, the disc repancy of alpha values between heating and cooling conditions was insignif icant when the heating (cooling) rate was reduced to 1 degreesC min(-1). It was revealed that alpha values obtained from 1 degreesC min(-1) cooling ra tes should be utilized. Dental porcelain with an a value lower than 8.5 x 1 0(-6) degreesC will be suitable for titanium-ceramic applications.