A method for testing and quantifying the adhesion strength of particulate coatings was developed. A gas impingement test was developed to measure adhesion forces of electrophoretically-deposited layers of phosphor particles for use as information display screens. A high pressure jet of nitrogen gas is directed perpendicularly to a particulate deposit. The particles are removed from the substrate in a ring pattern which can be correlated to the skin friction on the substrate, giving a measurement of adhesion strength in the range of 100 to 450 Pa.