Molybdenum disilicide heating element and its production method
AssigneeRiken
InventorsTetsuo Uchiyama, Wan Jiang
Life of this patent
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Abstract
The MoSi2 heating element has not been so resistant under the low-temperature heating, because the low-temperature oxidation, which is attributable to the grain boundary oxidation, occurred. In the present invention, long life under the low-temperature heating is attained by the following two structures. (1) The MoSi2 grains have a network structure and are linked three dimensionally. (2) The secondary, silica-bearing oxide or glass phase forms a net-like structure around the MoSi2 grains.
Claims16
A molybdenum-disilicide based ceramic composite heating element having long life at low-temperature heating, consisting essentially of molybdenum disilicide grains having a network structure and a secondary phase consisting of at least one material selected from the group consisting of a silicon-bearing oxide and a glass having a relatively low melting point as compared with said molybdenum disilicide, and further said secondary phase is distributed within said network structure in a net-like form along the boundaries of the said molybdenum disilicide grains.
A molybdenum-disilicide based ceramic composite heating element having long life at low-temperature heating, consisting essentially of molybdenum disilicide grains having a network structure, a secondary phase consisting of at least one material selected from the group consisting of a silicon-bearing oxide and a glass having a relatively low melting point as compared with said molybdenum disilicide, and 35% by volume or less of a ternary strengthening phase consisting of at least one compound selected from the group consisting of MoB, Mo2B, MoB2, Mo2B5, WB, W2B, WB2, W2B5, SiC, HfB2, ZrB2, TiB2, TiB, HfC, ZrC and TiC, having 5 μm or less of average particle diameter, with the proviso that the total of the secondary and ternary phases is 55% by volume or less, and further said secondary phase is distributed within said network structure in a net-like form along the boundaries of the said molybdenum disilicide grains.
Dependencies are inferred from the claim text.