Patent ID: 6180184
Filing Date: 2001-01-30
Classification: C23C,Y10T

Abstract:
A method for making a ceramic thermal barrier coating having a plurality of coherent, continuous columnar grains by plasma-spraying ceramic powder particles onto a substrate, the method comprising the steps of:maintaining a deposition surface, upon which the plurality of coherent, columnar grains are to be formed, at a temperature in a range between about 0.2 to about 0.5 of an absolute melting temperature of the ceramic powder used to form the thermal barrier coating, the step of maintaining the deposition surface comprises maintaining the temperature during plasma-spraying of the ceramic powder that is used to form the coherent, continuous columnar grains and maintaining the temperature as the ceramic powder contacts the substrate to form the columnar grains; andextracting heat associated with plasma-spraying to create a thermal gradient within the thermal barrier coating; andmaintaining the thermal gradient within the thermal barrier coating in which the temperature decreases in a direction opposite to a desired direction of growth for the coherent, continuous columnar grains,wherein localized remelting of the deposition surface occurs under heat from the ceramic powder particles and the maintaining of the deposition surface, the localized remelting and creation and maintaining the thermal gradient being sufficient to promote columnar directional solidification of incoming ceramic powder particles.