LAUSR

The hydrogen barrier properties of the coatings of nitride and diamondlike amorphous carbon (DLC) were evaluated. Using plasma chemical vapor deposition and sputtering, ZrN, TiAlN, AlCrN, CrN, and DLC coatings were deposited with a thickness of about 3 μm. It was confirmed that all coatings have an impact on decreasing the hydrogen permeation rate. Specifically, by coating stainless steel with a DLC coating, the hydrogen permeation rate was reduced to 1/1000 or lower compared to that without a coating. By providing a buffer layer of Cr-N, the hydrogen barrier function was improved. DLC coatings with high hydrogen content had an especially high hydrogen barrier function. For hydrogen diffusion in coatings, the movement of atoms through hydrogen trap sites is important. There are both sp3 and sp2 bonds in DLC coatings, and excess hydrogen can be found in the interstitial space and the above-mentioned hydrogen trap sites. It is suggested that the hydrogen trap sites in a DLC coating with high hydrogen content are likely already filled with hydrogen atoms, and the movement of new hydrogen atoms could be limited.The hydrogen barrier properties of the coatings of nitride and diamondlike amorphous carbon (DLC) were evaluated. Using plasma chemical vapor deposition and sputtering, ZrN, TiAlN, AlCrN, CrN, and DLC coatings were deposited with a thickness of about 3 μm. It was confirmed that all coatings have an impact on decreasing the hydrogen permeation rate. Specifically, by coating stainless steel with a DLC coating, the hydrogen permeation rate was reduced to 1/1000 or lower compared to that without a coating. By providing a buffer layer of Cr-N, the hydrogen barrier function was improved. DLC coatings with high hydrogen content had an especially high hydrogen barrier function. For hydrogen diffusion in coatings, the movement of atoms through hydrogen trap sites is important. There are both sp3 and sp2 bonds in DLC coatings, and excess hydrogen can be found in the interstitial space and the above-mentioned hydrogen trap sites. It is suggested that the hydrogen trap sites in a DLC coating with high hydrogen conten...