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铬酸镧电热元件是目前最好的陶瓷发热材料之一。通过X射线衍射和扫描电镜对国内外铬酸镧电热元件的结构特征进行了分析 ,利用定量金相截线法对试样的晶粒尺寸分布进行了统计。结果表明 ,国产铬酸镧电热元件由尺寸均匀的等轴晶组成 ,元件的热端在使用 2 0 0 0h后晶粒长大十分明显 ,并存在调幅分解。日本元件除细小的等轴晶外还有一定量的形状不规则的大晶粒 ,等轴晶在使用后长大不明显 ,这可能是其良好抗热震性的原因
Lanthanum chromate electric heating element is one of the best ceramic heating materials. The structural characteristics of the lanthanum chromite heating element at home and abroad were analyzed by X-ray diffraction and scanning electron microscopy. The grain size distribution of the sample was calculated by the method of quantitative metallographic intercept. The results show that the domestic lanthanum chromite heating element consists of equiaxed grains with uniform size. The hot end of the element is obviously grown after 2000h, and there is amplitude modulation decomposition. Japanese elements in addition to fine equiaxed grains there are a certain amount of irregular shape of large grains, equiaxed grains grew indistinctly after use, which may be the reason for its good thermal shock resistance