摘要 |
An auxiliary-layer-lined unfired ceramic body, having a step portion in a principal surface thereof, has an unfired ceramic body and an auxiliary layer which is adhered to one principal surface of the unfired ceramic body and which is made of a material that is substantially unsinterable at a temperature at which the unfired ceramic body is fired. The auxiliary-layer-lined unfired ceramic body is fired at a temperature at which the unfired ceramic body is sinterable but the auxiliary layer is substantially unsinterable, while the auxiliary layer remains adhered to the unfired ceramic body. A pressing operation is performed using a die having a projection placed on the side of the auxiliary-layer-lined unfired ceramic body retaining the auxiliary layer, so that the step portion, having a shape corresponding to the outer shape of the die projection, is formed in the side of the auxiliary-layer-lined unfired ceramic body retaining the auxiliary layer.
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