大孔洞 meaning in English
macroscopic void
Examples
- The analysis of microstructure of samples showed that the grain of tio2 were very small under 700 , the distance of grain became small with temperature increasing , the rate and size of pore was decreasing . the relative density of sample at 900 was 97 % and the grain size of sintered body was about 200nm . when the temperature exceeded 1100 , the grain size of body grew up several times ( > 2 m )
Tio _ 2烧结体sem显微形貌分析表明：低温( 700 )时坯体内颗粒无明显长大，烧结体致密度不高( 80 )晶粒间距随温度升高而变小，气孔率也随之降低，气孔尺寸变小；当温度超过900时，晶粒间连接紧密，烧结体内出现大量絮状物质，致密度大幅度提高，达97以上，小气孔已聚集成大孔洞且分布均匀，晶粒长大不明显( 200nm左右) ；当温度超过1100时，烧结体致密度有所提高，但晶粒尺寸出现异常长大，长大了十几倍(达2 m以上) 。