CVD coatings are applied at considerably high temperatures, normally between 925-1075 degrees centigrade. With the amount of energy that is required to apply the coatings can make failure at this stage an expensive mistake to correct.
With the nature of high temperature coatings, when applied to a cemented carbide surface, the process can create cooling cracks and particularly high tensile stresses; caused by the difference in the coefficients of thermal expansion between the two.