| 摘要 |
PURPOSE:To obtain a diaphragm, which has a characteristic of constant elasticity up to 130 deg.C and can measure with high precision differential pressure and pressure up to 100 deg.C, and moreover, has an excellent characteristic in corrosion resistance, by a method wherein a corrosion- resistant metal coated layer is provided on the surface of an alloy consisting of a precipitation hardened constant elasticity alloy composed of Ni, Co, Cr, Ti, Al and Zr, which are respectively a specified % in weight, the remnant Fe and incidental impurities. CONSTITUTION:The diaphragm is one that a corrosion-resistant metal coated layer of a thickness of 0.1-5% in a ratio (the thickness of a coated layer/the thickness of its base metal) of thickness was provided on the surface of an alloy, which has a constant elasticity and consists of 30.0-44.5wt% Ni, 0.4-15wt% Co, 4.0-6.5wt% Cr, 0.5-1.9wt% Ti, 0.1-1.0wt% Al, 0.2- 2.0wt% Zr, the remnant Fe and incidental impurities. The Ni maintains the characteristc of the constant elasticity of the alloy. When the wt% of the Ni is less than 30.0wt% and exceeds 44.5wt%, the characteristic of the effect of the constant elasticity is not obtained. The Co also maintains the characteristic of the constant elasticity of the alloy in the same manner as the Ni. Specially, as the Co makes the magnetic critical temperature of the alloy to rise, the Co contributes to it for the temperature range of the characteristic of the constant elasticity to improve. When the wt% of the Co is less than 0.4wt% and exceeds 15.0wt%, the effect of the constant elasticity cannot be sufficiently obtained. |
