摘要
团聚体结构通常用团聚系数来表征,团聚系数(AF)被定义为:团聚体的平均尺寸与基本颗粒尺寸之比值。每个团聚体都由实体部分—基本颗粒,空心部分—基本微粒之间的空隙两部分构成。团聚系数只表征了团聚体与构成它的基本微粒之间的关系。因而定义另一参数来表征团聚体结构中的空隙部分是非常有必要的。本文提出“孔系数”这一参数。孔系数(PF)被定义为:每克粉料中聚团内的气孔数与聚团数中之比值。PF 值由PF=(ρ_αV_pD^3/8r^3)×10~9推导。各种不同的氧化锆粉末是在不同热处理条件下处理氢氧化物而得到的。孔系数是根据离心沉降分析、压汞测孔的结果,经分析计算而得出。在粉末锻烧过程中,随着煅烧温度的提高和保温时间的延长(煅烧温度一定)孔系数降低。这种变化趋势可以经 TEM 观察到的结果得以证明。
Agglomeration coefficient,AF,the ratio between the mean size of agglomera-tes and the primary particle size,is widely used for description of agglomeratestructures.Since an agglomerate consists of both solid part,i.e.primary particles,and hollow part,i.e.pores between the primary particles,the agglomerationcoefficient,AF,reflects only on the solid part of the agglomerate structure.Therefore,it is necessary to define another parameter to describe the hollow partof the structure.In this paper,a parameter,named as pore factor,PA,is given,whose definition is known as a ratio between the number of pores in agglomeratesper one gram of powder and the number of agglomerates per one gram of powder.the following equation was derived for estimation of the value of PF.PF=(ρ_aV_pD^3/8 r^3)x10^(?)where ρ_a is mean density of agglomerates (g/cm^3),V_p is volume of pores inagglomerates per one gram of powder (mm^3/g),r is mean pore radius in agglo-merates((?)),D is mean diameter of agglomerates(μm).The pore factors for various zirconia powders derived from hydroxide by dif-ferent heat treatments were calculated from the data obtained from sedimentalparticle analysis,surface area measurements,and mercury porosimetry.It wasfound that the values of pore factor decreased with the increase of calciningtemprature and soaking time.This trend was verified by TEM investigation ofagglomerates.
出处
《无机材料学报》
SCIE
EI
CAS
CSCD
北大核心
1989年第4期330-335,共6页
Journal of Inorganic Materials
关键词
陶瓷粉末
团聚体
孔系数
Ceramic powder
Agglomerates
Pore factor
