Investigations of Wetting Properties of Stainless Steel by Molten Multi-component Oxides

The wettability between molten impregnating materials and thermal spray coatings is an important factor in post-treatment process of porous coatings. Here, we present the study of wetting behavior of stainless steel substrates by multi-component oxides, using the sessile drop method. The multi-component oxides was mainly composed by SiO2 and Al2O3 and also with a little K2O, Na2O etc. At 1273K and 1353K, we found that the contact angles stabilized at around 45 degrees and 75 degrees respectively. The micro-observation confirmed that the evaporation of alkali metal oxides become a leading position in molten multi-component oxides evaporation at 1353K. As a result, the rupture of Na-O and K-O bonds will occur and lattice network structure of multi-component oxides reconstruct at excessively high temperature, leading the molten oxides to a higher viscosity and poorer wettability. As the basic researches, this paper also provide a theoretical basis for the deeply study on the post penetration treatment.