Kovar heat treatment of the wire body
Kovar.
Kovar – precision magnetic alloy containing Nickel (29 %), cobalt (17 %) and iron (54 %). The alloy composition also includes carbon (less than 0.01 %), silicon (0.2 %) and manganese (0.3 percent).
Alloys
Description:
Kovar – precision magnetic alloy containing Nickel (Ni) (29 %), cobalt (Co) (17 %) and iron (Fe) (54 %). The alloy composition also includes carbon (C) (less than 0.01 %), silicon (Si) (0.2 %) and manganese (Mn) (0,3 %).
Kovar has a coefficient of thermal expansion matched with the coefficient of thermal expansion of borosilicate glass, and has a high adhesion to molten glass, and therefore is widely used for making electrical conclusions, passing through glassand cold end variety of lamps, devices, radioactive elements.
Properties:
– alloy plastic, well-rolled, drawn, stamped, welded, soldered,
– has a high adhesion to the molten glass,
the ferromagnetic alloy,
the Curie temperature is 420 °C,
– melting point 1450 °C,
– electrical resistivity of 0.5 MOhm·m,
– in a humid environment the alloy corrode requires protective anti-corrosion coatings (usually, for this purpose made of an alloy findings nicelybut),
– well laditsya alloy tin-lead solders,
– when soldering with the glass, forms a secure vacuum and a tight grip,
– 8 density 350 kg/m3,
– the modulus of elasticity of 1.96·1011 PA (N/m2),
the normal elasticity modulus (E) 14 500·10-1 N/mm2,
– tensile strength of 0.65 GPA (65 kgf/mm2),
– the thermal conductivity of 19 W/(m·K),
– electrical resistivity of 0.15·10-6 Ohm·m,
– the coercive force of 74 vehicles
– the initial magnetic permeability of 0.78 mH/m,
– the maximum magnetic permeability of 6.36 mH/m,
– residual induction of the magnetic field 9 750·10-4 T,
– induction into the field 8E (В8э) 13250·10-4 T,
– coefficient of thermal expansion is (4,5 – 5,2)·10-6 1/°C in the interval 20 – 400 °C and ~ 10·10-6 1/K at 800 °C, close to the thermal expansion coefficient of the glass.
