Heat transfer from a chemically oxidized or anodized copper plate to liquid helium

Heat transfer characteristics between a copper plate (50 mm × 10 mm) and liquid helium have been measured for two kinds of surfaces, i.e. the surfaces were chemically oxidized and anodized. The experimental results showed the critical heat fluxes, qCHF, do not change between the different oxidization samples. But the minimum heat fluxes, qMHF, have a variation, which may have been caused from the growth of other components than copper oxide on surface. The formation of matrix –COOH in chemically oxidized sample became clear by X-ray photo-electron spectroscopy (XPS), and a different compactness on surface was indicated by scanning electron microscopy (SEM).