An evaluation of the effect of porcelain firing cycles on the properties of co-cr casting alloys

To satisfy the demand of esthetic restorations, PFM prosthesis were introduced which also had sufficient strength. In the process of fabrication of PFM prosthesis, the alloy sbstructure is layered with various layes of powdered ceramics which is subjected to sintering process at high temperatures. At least three such firing cycles are needed which may result in alteration of properties of metal alloy sbstructure. Co-Cr is one of the most common base maetal alloy used for this purpose which is used in this study. The bar & disc shaped specimens were fabricated from Co-Cr alloys and were divided in various groups. The bar specimens were subjected to Ultimate Tensile Testing and disc specimens were subjected to X Ray Diffraction and Vickers Hardness Test. The UTS values of the Co-Cr ally decreases where as the HV values increases with increase in firing cycles. The changes in XRD patterns were also consistent.