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采用人工引入夹杂粒子的方法,制得含缺陷的热压陶瓷样品(Si_3N_4,SiC 和 ZrO_2)。籍助200MHz 的高频超声手段,研究了适用于陶瓷缺陷无损检测的技术参数和影响缺陷检测的陶瓷材质的特性条件,以及导至声波衰减的技术和材质因素。分析了缺陷的大小、方位和特性与反射波的强度,亦即示波器上的缺陷波幅之间的关系。证实了200MHz 高频超声技术用于检测致密陶瓷体内微缺陷(80～100μm 尺寸的 Pt,W,Si,MgO 和 MoSi_2夹杂粒子)的合适性。确定了欲达到良好检测效果必需具备的陶瓷材质条件:1.致密度>95%理论密度;2.显微结构参数(晶粒,气孔径,第二相粒子)的尺寸比被检缺陷小1～2个数量级;3.表面光洁度≈V_(?);4.有效检测深度5～10mm(取决于陶瓷基体材质);5.陶瓷基体和缺陷的声阻抗差别要大。
Using the method of introducing inclusions by hand, the hot pressed ceramic samples (Si 3 N 4, SiC and ZrO 2) with defects were obtained. With 200MHz high-frequency ultrasound means, the technical parameters suitable for non-destructive testing of ceramic defects and the characteristics of ceramic materials influencing the defect detection as well as the technical and material factors leading to acoustic attenuation are studied. The relationship between the size, orientation and characteristics of the defects and the intensity of the reflected waves, that is, the defect amplitude on the oscilloscope, is analyzed. The applicability of 200MHz high-frequency ultrasound for the detection of microdefects (Pt, W, Si, MgO and MoSi 2 inclusions) in dense ceramic bodies was confirmed. Determine the ceramic materials required to achieve a good detection effect: 1. Density> 95% theoretical density; 2. The microstructure parameters (grain size, pore size, second phase particles) smaller than the size of the defect being inspected ~ 2 orders of magnitude; 3. Surface finish ≈V _ (?); 4. Effective depth of detection of 5 ~ 10mm (depending on the ceramic substrate material); 5. Ceramic substrate and defect acoustic impedance differences.