A trial of quantitative estimation of Al-corrosion detected by neutron radiography.
Comparing the hydrogen content in aluminum hydroxides, one of the main components of Al-corrosion, with that in polyethylene sheets, corroded degree of practical Al-corrosions were estimated quantitatively by neutron radiography.
The Sensitivity of Neutron Radiography for Detection of Aluminium Corrosion Products
Within a feasibility study concerning the introduction of neutron radiography as a nondestructive method into the domestic aircraft industry and for the maintenance of domestic commercial civil aircraft, the sensitivity of neutron radiography for detection of A1 corrosion products was studied experimentally. The mass thickness of a large area surface corrosion deposit which could be easily detected through thick (1 – 2 cm) Al slabs was found to be at least 0.02 g/cm2. The minimal detectable mass thickness of corrosion products depends on the relative amount of A1(0H)3 and A10(0H), moisture and possible organic materials in their composition and should be in the range of 0.01 – 0.02 g/cm2.
Neutron Radiography for Nondestructive Testing
Neutron radiography is similar to x-ray inspection in that both depend upon use of radiation that penetrates some materials and is absorbed by others to provide a contrast image of conditions not readily available for visual inspection. But an important difference is the type of materials that absorb each of the two kinds of radiation. X-rays are absorbed by dense materials, such as metals, whereas neutrons readily penetrate metals but are absorbed by materials containing hydrogen.