Laser-based ultrasonic measurements of cellular ceramic bodies during thermal processing

A laser-based ultrasonic system for measuring at least one material property of a ceramic cellular ceramic body during thermal processing, comprising:

• a) an oven having first and second windows and an interior, and containing in the interior the ceramic cellular ceramic body, the oven being configured to subject the ceramic cellular ceramic body to a temperature cycle;
• b) a laser generator system configured to generate and sequentially direct a modulated first laser beam through the first window and onto the cellular ceramic body at a plurality of first locations so as to generate acoustic waves over a plurality of acoustic paths within the cellular ceramic body;
• c) a laser detector system configured to generate and sequentially direct a second laser beam through the second window and onto the cellular ceramic body at a plurality of second locations that correspond to the plurality of first locations so as to detect the acoustic waves and form therefrom a corresponding plurality electrical detector signal representative of the detected acoustic waves;
• and
• d) a processor configured to receive and process the electrical detector signals and calculate the at least one material property.

A method of measuring at least one material property of a ceramic cellular ceramic body during thermal processing, comprising:

• a) arranging ceramic cellular ceramic body in an oven having an adjustable temperature and first and second windows;
• b) adjusting the oven temperature, and for each of a plurality of oven temperatures:
• sequentially irradiating the cellular ceramic body at a plurality of first locations with a modulated laser beam that passes through a first window to generate acoustic waves over a plurality of acoustic paths within the ceramic cellular body;
• c) sequentially irradiating the cellular ceramic body at a plurality of second locations that correspond to the plurality of the first locations through the second window using a detection laser beam to detect the acoustic waves for the plurality of acoustic paths and forming a corresponding plurality of electrical detector signals representative of the detected acoustic waves;
• and
• d) calculating from the one or more electrical detector signals the at least one material property as a function of location and temperature.