Method for determining the thermal expansion coefficient of ceramic bodies and glazes
OwnerWilliam M. Cartyinventor
Life of this patent
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Abstract
A method of measuring the coefficient of thermal expansion of a ceramic material, including the steps of applying a glaze to a substantially densified refractory body, wherein the coefficient of thermal expansion of either the glaze or the body is known, bonding the glaze to the body, putting the glaze insufficient tension to induce crazing, measuring the average distance between cracks in the crazed glaze; and determining the unknown coefficient of thermal expansion of the glaze or body.
Claims21
A method of determining the coefficient of thermal expansion of a glaze or a refractory body, comprising:
- a) applying a glaze to the refractory body, wherein the refractory body is a substantially densified refractory body, wherein the glaze is characterized by a known elastic modulus, wherein the glaze is characterized by a known failure stress, wherein the glaze is characterized by a known glass transition temperature, and wherein the coefficient of thermal expansion of one of the glaze or the refractory body is known and the coefficient of the other of the glaze or the refractory body is unknown;
- b) bonding the glaze to the refractory body;
- c) putting the glaze into sufficient tension to induce crazing and to create cracks;
- d) measuring the average distance between cracks in the crazed glaze;
- and
- e) determining the unknown coefficient of thermal expansion of the glaze or refractory body according to the relationship wherein the difference between the known and unknown coefficients of thermal expansion is proportional to the failure stress of the glaze divided by the product of the elastic modulus of the glaze, the distance between the cracks in the crazed glaze, and the difference between the glass transition temperature of the glaze and the ambient temperature.
A method of determining the coefficient of thermal expansion of a glaze or refractory body, comprising:
- a) applying a glaze to a refractory body to yield a glazed body, wherein the glaze and the refractory body are each characterized by a respective coefficient of thermal expansion, wherein the glaze is characterized by a known elastic modulus, wherein the glaze is characterized by a known failure stress, wherein the glaze is characterized by a known glass transition temperature, wherein one of the respective coefficients of thermal expansion is known and the other respective coefficient of thermal expansion is unknown;
- b) firing the glazed body to as first predetermined temperature;
- c) crazing the glaze on the glazed body to create cracks;
- d) measuring the average distance between cracks in the crazed glaze;
- and
- e) determining the unknown coefficient of thermal expansion by using the relation between the coefficient of thermal expansion of the glaze, the coefficient of thermal expansion of the refractory body, the failure stress of the glaze, the elastic modulus of the glaze, the glass transition temperature of the glaze, ambient temperature after cooling and the average distance between of the cracks in the crazed glaze.
A method of determining the coefficient of thermal expansion of a glaze or a refractory body, comprising:
- a) applying a glaze to a refractory body to yield a glazed body, wherein the glaze and the refractory body are each characterized by a respective coefficient of thermal expansion, wherein one of the respective coefficients of thermal expansion is known and the other respective coefficient of thermal expansion is unknown;
- b) firing the glazed body to as first predetermined temperature;
- c) crazing the glaze on the glazed body and creating cracks;
- d) recording the average distance between cracks in the crazed glaze;
- and
- e) determining the unknown coefficient of thermal expansion from the average distance between cracks in the crazed glaze, the firing temperature, and the known coefficient of thermal expansion.
Dependencies are inferred from the claim text.