Coating method for non-destructive examination of articles of manufacture
View Patent ↗A method for non-destructive evaluation of an article of manufacture ( 30 ) by coating the article with a temperature-sensitive coating ( 34 ), stimulating the article with energy ( 18 ) to induce temperature changes in the article responsive to features of the article, then evaluating ( 24 ) a resulting topography of energy-induced changes ( 50, 52, 53 ) in the coating ( 34 ). The energy imparted to the article may be, for example, electromagnetic, magnetic, or sonic energy that produces localized changes in temperature in the article ( 30 ) in response to features ( 32 ) of the article such as flaws or other discontinuities. The coating ( 34 ) may be a suspension of liquid crystals in a liquid, and the energy may be an application of sonic energy. The coating may be a material that hardens ( 42, 54 ) or softens ( 44, 56 ) upon a slight increase in temperature. Layers ( 34, 35 ) of different energy-sensitive coatings ( 38, 40 ) may be applied to indicate different aspects of features of the article.
1. A method for non-destructive evaluation of an article of manufacture, the method comprising the following sequence of steps:
coating a surface of the article with a temperature-sensitive coating;
stimulating the article with an evaluation energy that preferentially generates heat in the article proximate a flaw therein, producing temperature-induced changes in the temperature-sensitive coating that visibly indicate the flaw in the article, wherein the evaluation energy is selected and controlled for evaluation of the article;
evaluating the article via the temperature-induced changes in the temperature sensitive coating;
conducting a repair on the article using the temperature-induced changes in the temperature-sensitive coating on the surface of the article as a guide for locating the repair; wherein:
the coating step comprises applying the temperature-sensitive coating in a grid pattern at a particular scale on the surface; and
the evaluating step comprises evaluating the temperature-induced changes in conjunction with the grid pattern to determine a dimension of the flaw in the article.
2. A method for non-destructive evaluation of an article of manufacture, the method comprising the following sequence of steps:
coating a surface of the article with a temperature-sensitive coating;
stimulating the article with an evaluation energy that preferentially generates heat in the article proximate a flaw therein, producing temperature-induced changes in the temperature-sensitive coating that visibly indicate the flaw in the article, wherein the evaluation energy is selected and controlled for evaluation of the article;
evaluating the article via the temperature-induced changes in the temperature sensitive coating;
conducting a repair on the article using the temperature-induced changes in the temperature-sensitive coating on the surface of the article as a guide for locating the repair; wherein:
the coating step comprises applying the temperature-sensitive coating in a grid pattern at a particular scale on the surface;
the evaluating step comprises evaluating the temperature-induced changes in conjunction with the grid pattern to determine a dimension of the flaw in the article;
the coating step further comprises applying the grid pattern at a particular position on the surface; and
the evaluating step further comprises evaluating the temperature-induced changes in conjunction with both the position and the scale of the grid pattern to determine a location and the dimension of the flaw.
3. The method of claim 1 wherein the article is a turbine blade.
4. The method of claim 2 wherein the article is a turbine blade.