| 摘要 |
PURPOSE:To foresee simply rupture strength at high temp. by measuring previously a relation of stresses from normal to high temp. when an Si3N4 ceramic produces a sound by extremely small rupturing, and measuring a stress during the sound production of said ceramic at normal temp.. CONSTITUTION:A resistance wire 11 such as nichrome wire is embedded at a neutral surface (place equivalent to 1/2 of plate thickness) of the Si3N4 ceramic 10 to heat electrically the wire 11. The stresses during the sound production at each temp. T from normal temp. to 1000 deg.C are measured by placing the test piece 10 on supporters 3, 4 as shown in a separate figure to obtain previously a temp. and stress relation shown by an equation (deltaAE.RT is stress at normal temp., deltaAE.HT is that at high temp.). A graph made from the equation is also permissible. The stress of a Si3N4 test piece 1 to be inspected during the sound production at normal temp. is obtained by detecting by sensors 5, 6 the sound caused by the fine rupture generation by pushing a pressing part 2 in an arrow direction. The rupture strength at desired high temp. can be foreseen simply by using the relating equation or the graph from the stress thereat. |
