| 摘要 |
PURPOSE:To make the shape and diameter of powder particles uniform and to decrease the variation of gas inductive characteristics by applying a precipitation forming reaction utilizing a hydrolysis of urea to the adjustment of the raw material powder of a gas-inductive body. CONSTITUTION:Indium chloride, ammonium sulfate and urea [(NH2)2CO] are dissolved in water and stirred while heating them on a hot plate. The heating is conducted e.g. at >=95 deg.C temp. The coprecipitated material is filtered by sucking, the obtained powder is fed into evacuating vessel for vacuum drying, pulverized by an automated mortar, and then adjusted to particles of the size of about 100-200mu by using an organic binder. Two platinum wires as serving as an electrode are embedded into this powder, then pressformed, and ignited in air to manufacture a gas inspecting element. This gas inspecting element has small variation of the gas-inductive characteristics because the shape and diameter of the raw material powder of the gas-inductive body are uniform, and the characteristics are stable for a long time. |
