Cavitation, Tensile Strength, and the Surface Films of Gas Nuclei 



Table 5 

 Tensile Strength Between Water and Polymers 



Should tensile strengths greater than 40 psi be desired, not many types of 

 materials need to be prohibited from use, since high- strength bonds (70 psi and 

 greater) were obtained with many common materials, including metals, metallic 

 oxides, ceramics, clays, and silicates. In practice, obtaining a high tensile 

 strength would generally mean avoiding materials of a hydrocarbon nature such 

 as rubbers, plastics and paints, should they be shown to possess a low tensile 

 strength with water. 



It is also to be noted that low tensile strength materials possess large wet- 

 ting angles, and so are undesirable in any event because of their ability to re- 

 tain bubbles on the surface of the material. 



STRENGTH OF SEA WATER 



From the preceding discussion of solid materials, one can conclude that it 

 is unlikely that solids causing low bond strength are to be found as natural con- 

 taminants in ocean or inland waters. Tests were also performed to show that 

 dissolved salts and impurities did not weaken water enough to promote cavita- 

 tion in the 100-psi range of interest, for concentrations likely to be encountered 



87 



