of about 11 u00d7 10 6 do not cause so large heat contraction slide hoppers composed of the raw materials with this degree of coefficient of linear expansion are not sufficient for forming a thin layer by high speed coating and that raw materials with a coefficient of linear expansion of 3 u00d7 10 6 or less are required for preventing changes in the gap between the lip and the web generated by forming a thin layer by high speed coating in the present invention determination of the composition of alloy as described above has been conducted by the following reasons a chromium content below 9 0 by weight deteriorates resistance of the resulting alloy to corrosion whereas a chromium content exceeding 10 5 by weight increases the coefficient of linear expansion a cobalt content below 52 5 by weight reduces the coefficient of linear expansion but deteriorates the resistance to corrosion a cobalt content exceeding 56 0 by weight improves the resistance to corrosion but increases the coefficient of linear expansion to exceed the upper limit thereof in the present invention solvents usable for forming a thin layer by stable high speed coating are organic volatile solvents such as acetone methanol methylene chloride ethanol methyl ethyl ketone ethyl acetate methyl acetate xylene toluene cyclohexane cyclohexanone propanol and butanol although the present invention is useful for organic solvent based coating solutions a mixture of water and an organic solvent can also be suitably used for a coating solution in the invention to solve the same problems as described above which the mixture also encounters when the organic solvent is a main component of the mixtures further.